Appearance from Earth

The Milky Way Galaxy, as viewed from Earth’s position in a spur of one of the galaxy’s spiral arms (see Sun’s location and neighborhood), appears as a hazy band of white light in the night sky arching across the entire celestial sphere. The light originates from stars and other material that lie within the galactic plane. The plane of the Milky Way is inclined by about 60 to the ecliptic (the plane of the Earth’s orbit), with the North Galactic Pole situated at right ascension 12h 49m, declination +27.4 (B1950) near beta Comae Berenices. The South Galactic Pole is near alpha Sculptoris.

The center of the galaxy lies in the direction of Sagittarius, and it is here that Milky Way looks brightest. Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth’s equatorial plane and the plane of the ecliptic relative to the galactic plane. From Sagittarius, the Milky Way appears to pass westward through the constellations of Scorpius, Ara, Norma, Triangulum Australe, Circinus, Centaurus, Musca, Crux, Carina, Vela, Puppis, Canis Major, Monoceros, Orion & Gemini, Taurus, Auriga, Perseus, Andromeda, Cassiopeia, Cepheus & Lacerta, Cygnus, Vulpecula, Sagitta, Aquila, Ophiuchus, Scutum, and back to Sagittarius. The fact that the Milky Way divides the night sky into two roughly equal hemispheres indicates that the Solar System lies close to the galactic plane. The Milky Way has a relatively low surface brightness due to the interstellar medium that fills the galactic disk, and preventing us from seeing the bright galactic center. It is thus difficult to see from any urban or suburban location suffering from light pollution.

Panoramas

360-degree photographic panorama of the galaxy.

A panorama of the Milky Way, as seen from Death Valley, 2005.

The plane of our Milky Way Galaxy, which we see edge-on from our perspective on Earth, cuts a luminous swath across the image. Credit: ESO/S. Brunier

The Milky Way arches across this rare 360-degree panorama of the night sky above the Paranal platform, home of ESO Very Large Telescope. The image was made from 37 individual frames with a total exposure time of about 30 minutes, taken in the early morning hours. The Moon is just rising and the zodiacal light shines above it, while the Milky Way stretches across the sky opposite the observatory. Credit: ESO/H. Heyer

Size

The Galactic Plane seen by the ATLASGAL survey, divided into sections. Credit ESO.

The stellar disk of the Milky Way Galaxy is approximately 100,000 light-years (91017 km) (61017 mi) in diameter, and is considered to be, on average, about 1,000 ly (91015 km) thick. It is estimated to contain at least 200 billion stars and possibly up to 400 billion stars, the exact figure depending on the number of very low-mass stars, which is highly uncertain. This can be compared to the one trillion (1012) stars of the neighbouring Andromeda Galaxy. The stellar disc does not have a sharp edge, a radius beyond which there are no stars. Rather, the number of stars drops smoothly with distance from the centre of the Galaxy. Beyond a radius of roughly 40,000 light-years (41017 km) the number of stars drops much faster with radius , for reasons that are not understood.

Extending beyond the stellar disk is a much thicker disk of gas. Recent observations indicate that the gaseous disk of the Milky Way has a thickness of around 12,000 ly (11017 km)wice the previously accepted value. As a guide to the relative physical scale of the Milky Way, if it were reduced to 10m in diameter, the Solar System, including the hypothesized Oort cloud, would be no more than 0.1mm in width.

The Galactic Halo extends outward, but is limited in size by the orbits of two Milky Way satellites, the Large and the Small Magellanic Clouds, whose perigalacticon is at 180,000 ly (21018 km). At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds, and the objects would likely be ejected from the vicinity of the Milky Way.

Recent measurements by the Very Long Baseline Array (VLBA) have revealed that the Milky Way is much more massive than some previously thought. The mass of our home galaxy is now considered to be roughly similar to that of our largest local neighbour, the Andromeda Galaxy. By using the VLBA to measure the apparent shift or parallax of far-flung star-forming regions when the Earth is on opposite sides of the Sun, the researchers were able to measure the distance to those regions using fewer assumptions than prior efforts. The newer and more accurate estimate of the galaxy’s rotational speed (and in turn the amount of dark matter contained by the galaxy) is about 254 km/s, significantly higher than the widely accepted value of 220 km/s. This in turn implies that the Milky Way has a total mass of approximately 3 trillion solar masses, about 50% more massive than previously thought.

Age

Main articles: Galaxy formation and evolution and nucleocosmochronology

A green and red Perseid meteor streaks across the sky just below the Milky Way in August 2007.

As of 2004, the age of the oldest star in the galaxy yet discovered, HE 1523-0901, is estimated to be about 13.2 billion years, nearly as old as the Universe. This estimate was determined using the UV-Visual Echelle Spectrograph of the Very Large Telescope to measure the beryllium content of two stars in globular cluster NGC 6397.citation needed The elapsed time between the rise of the first generation of stars in the Milky Way and the first generation of stars in the cluster was deduced to be 200 million to 300 million years. By including the estimated age of the stars in the globular cluster, 13.4 0.8 billion years, the estimated age of the oldest stars in the Milky Way is 13.6 0.8 billion years. The Galactic thin disk is estimated to have been formed between 6.5 and 10.1 billion years ago.

Composition and structure

The galactic center in the direction of Sagittarius. The primary stars of Sagittarius are indicated in red.

The galaxy consists of a bar-shaped core region surrounded by a disk of gas, dust and stars forming four distinct arm structures spiralling outward in a logarithmic spiral shape (see Spiral arms). The mass distribution within the galaxy closely resembles the Sbc Hubble classification, which is a spiral galaxy with relatively loosely-wound arms. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1990s. Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 which showed the galaxy’s central bar to be larger than previously suspected.

The Milky Way’s mass is thought to be about 5.8  1011 solar masses (M) comprising 200 to 400 billion stars. Its integrated absolute visual magnitude has been estimated to be 20.9. Most of the mass of the galaxy is thought to be dark matter, forming a dark matter halo of an estimated 6003000 billion M which is spread out relatively uniformly.

Galactic Center

Main article: Galactic Center

Observed structure of the Milky Way’s spiral arms. Our Sun is in the Local Spur.

The galactic disc, which bulges outward at the galactic center, has a diameter of between 70,000 and 100,000 light-years. The distance from the Sun to the galactic center is now estimated at 26,000 1400 light-years, while older estimates could put the Sun as far as 35,000 light-years from the central bulge.

The galactic center harbors a compact object of very large mass as determined by the motion of material around the center. The intense radio source named Sagittarius A*, thought to mark the center of the Milky Way, is newly confirmed to be a supermassive black hole. For a photo see Chandra X-ray Observatory; Jan. 6, 2003. Most galaxies are believed to have a supermassive black hole at their center.

The galaxy’s bar is thought to be about 27,000 light-years long, running through its center at a 44 10 degree angle to the line between the Sun and the center of the galaxy. It is composed primarily of red stars, believed to be ancient (see red dwarf, red giant). The bar is surrounded by a ring called the “5-kpc ring” that contains a large fraction of the molecular hydrogen present in the galaxy, as well as most of the Milky Way’s star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of our own galaxy.

Spiral arms

Observed and extrapolated structure of the spiral arms.

Artist’s conception of the spiral structure of the Milky Way with two major stellar arms and a bar.

Each spiral arm describes a logarithmic spiral (as do the arms of all spiral galaxies) with a pitch of approximately 12 degrees. Until recently, there were believed to be four major spiral arms which all start near the galaxy’s center. These are named as follows, according to the image at right:

Color

Arm(s)

cyan

3-kpc and Perseus Arm

purple

Norma and Outer arm (Along with a newly discovered extension)

green

Scutum-Crux Arm

pink

Carina and Sagittarius Arm

There are at least two smaller arms or spurs, including:

orange

Orion-Cygnus arm (which contains the Sun and Solar System)

Observations presented in 2008 by Robert Benjamin of the University of Wisconsin-Whitewater suggest that the Milky Way possesses only two major stellar arms: the Perseus arm and the Scutum-Centaurus arm. The rest of the arms are minor or adjunct arms. This would mean that the Milky Way is similar in appearance to NGC 1365.

Outside of the major spiral arms is the Monoceros Ring (or Outer Ring), proposed by astronomers Brian Yanny and Heidi Jo Newberg, a ring of gas and stars torn from other galaxies billions of years ago.

As is typical for many galaxies, the distribution of mass in the Milky Way Galaxy is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike the situation within the Solar System, where two-body gravitational dynamics dominate and different orbits are expected to have significantly different velocities associated with them. This difference is one of the major pieces of evidence for the existence of dark matter. Another interesting aspect is the so-called “wind-up problem” of the spiral arms. If the inner parts of the arms rotate faster than the outer part, then the galaxy will wind up so much that the spiral structure will be thinned out. But this is not what is observed in spiral galaxies; instead, astronomers propose that the spiral pattern is a density wave emanating from the galactic center. This can be likened to a moving traffic jam on a highway the cars are all moving, but there is always a region of slow-moving cars. This model also agrees with enhanced star formation in or near spiral arms; the compressional waves increase the density of molecular hydrogen and protostars form as a result.

Halo

The galactic disk is surrounded by a spheroid halo of old stars and globular clusters, of which 90% lie within 100,000 light-years, suggesting a stellar halo diameter of 200,000 light-years. However, a few globular clusters have been found farther, such as PAL 4 and AM1 at more than 200,000 light-years away from the galactic center. While the disk contains gas and dust which obscure the view in some wavelengths, the spheroid component does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but not in the halo. Open clusters also occur primarily in the disk.

Recent discoveries have added dimension to the knowledge of the Milky Way’s structure. With the discovery that the disc of the Andromeda Galaxy (M31) extends much further than previously thought, the possibility of the disk of our own galaxy extending further is apparent, and this is supported by evidence of the newly discovered Outer Arm extension of the Cygnus Arm. With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, it was found that a ring of galactic debris from its interaction with the Milky Way encircles the galactic disk.

On January 9, 2006, Mario Juri and others of Princeton University announced that the Sloan Digital Sky Survey of the northern sky found a huge and diffuse structure (spread out across an area around 5,000 times the size of a full moon) within the Milky Way that does not seem to fit within current models. The collection of stars rises close to perpendicular to the plane of the spiral arms of the galaxy. The proposed likely interpretation is that a dwarf galaxy is merging with the Milky Way. This galaxy is tentatively named the Virgo Stellar Stream and is found in the direction of Virgo about 30,000 light-years away.

Sun’s location and neighborhood

The Sun (and therefore the Earth and the Solar System) may be found close to the inner rim of the galaxy’s Orion Arm, in the Local Fluff inside the Local Bubble, and in the Gould Belt, at a distance of 7.620.32 kpc (25,0001,000 ly) from the Galactic Center. The Sun is currently 530 parsecs from the central plane of the galactic disc. The distance between the local arm and the next arm out, the Perseus Arm, is about 6,500 light-years. The Sun, and thus the Solar System, is found in the galactic habitable zone.

There are about 208 stars brighter than absolute magnitude 8.5 within 15 parsecs of the Sun, giving a density of 0.0147 such stars per cubic parsec, or 0.000424 per cubic light-year (from List of nearest bright stars). On the other hand, there are 64 known stars (of any magnitude, not counting 4 brown dwarfs) within 5 parsecs of the Sun, giving a density of 0.122 stars per cubic parsec, or 0.00352 per cubic light-year (from List of nearest stars), illustrating the fact that most stars are less bright than absolute magnitude 8.5.

The Apex of the Sun’s Way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun’s galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun’s orbit around the Galaxy is expected to be roughly elliptical with the addition of perturbations due to the galactic spiral arms and non-uniform mass distributions. In addition, the Sun oscillates up and down relative to the galactic plane approximately 2.7 times per orbit. This is very similar to how a simple harmonic oscillator works with no drag force (damping) term. These oscillations often coincide with mass extinction periods on Earth; presumably the higher density of stars close to the galactic plane leads to more impact events.

It takes the Solar System about 225250 million years to complete one orbit of the galaxy (a galactic year), so it is thought to have completed 2025 orbits during the lifetime of the Sun and 1/1250 of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Galaxy is approximately 220 km/s. At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit).

A diagram of our location in the Local Supercluster. Click to view more detail.

Environment

Main articles: Local group and Andromeda-Milky Way collision

Broad infrared view of our Milky Way Galaxy from the Spitzer Space Telescope created from more than 800,000 frames. This is the most detailed infrared picture of our galaxy to date.

Milky way starscape taken from Paranal.

Location of the starscape in relation to the rest of the galaxy.

The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, itself being part of the Virgo Supercluster.

Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 20,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a peculiar streamer of neutral hydrogen gas connecting these two small galaxies. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way. Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest Milky Way dwarf galaxies are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies, which are dynamically bound to the Milky Way, as well as some that have already been absorbed by the Milky Way, such as Omega Centauri. Observations through the zone of avoidance are frequently detecting new distant and nearby galaxies. Some galaxies consisting mostly of gas and dust may also have evaded detection so far.

In January 2006, researchers reported that the heretofore unexplained warp in the disk of the Milky Way has now been mapped and found to be a ripple or vibration set up by the Large and Small Magellanic Clouds as they circle the Galaxy, causing vibrations at certain frequencies when they pass through its edges. Previously, these two galaxies, at around 2% of the mass of the Milky Way, were considered too small to influence the Milky Way. However, by taking into account dark matter, the movement of these two galaxies creates a wake that influences the larger Milky Way. Taking dark matter into account results in an approximately twenty-fold increase in mass for the Galaxy. This calculation is according to a computer model made by Martin Weinberg of the University of Massachusetts, Amherst. In this model, the dark matter is spreading out from the galactic disc with the known gas layer. As a result, the model predicts that the gravitational effect of the Magellanic Clouds is amplified as they pass through the Galaxy.

Current measurements suggest the Andromeda Galaxy is approaching us at 100 to 140 kilometers per second. The Milky Way may collide with it in 3 to 4 billion years, depending on the importance of unknown lateral components to the galaxies’ relative motion. If they collide, individual stars within the galaxies would not collide, but instead the two galaxies will merge to form a single elliptical galaxy over the course of about a billion years.

Velocity

Galaxy rotation curve for the Milky Way. Vertical axis is speed of rotation about the galactic center. Horizontal axis is distance from the galactic center in kpcs. The sun is marked with a yellow ball. The observed curve of speed of rotation is blue. The predicted curve based upon stellar mass and gas in the Milky Way is red. Scatter in observations roughly indicated by gray bars. The difference is due to dark matter or perhaps a modification of the law of gravity.

In the general sense, the absolute velocity of any object through space is not a meaningful question according to Einstein’s special theory of relativity, which declares that there is no “preferred” inertial frame of reference in space with which to compare the object’s motion. (Motion must always be specified with respect to another object.) This must be kept in mind when discussing the Galaxy’s motion.

Astronomers believe the Milky Way is moving at approximately 630 km per second relative to the local co-moving frame of reference that moves with the Hubble flow. If the Galaxy is moving at 600 km/s, Earth travels 51.84 million km per day, or more than 18.9 billion km per year, about 4.5 times its closest distance from Pluto. The Milky Way is thought to be moving in the direction of the Great Attractor. The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda galaxy) is part of a supercluster called the Local Supercluster, centered near the Virgo Cluster: although they are moving away from each other at 967 km/s as part of the Hubble flow, the velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.

Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at around 552 km/s with respect to the photons of the CMB, toward 10.5 right ascension, -24 declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction.citation needed

The galaxy rotates about its center according to its galaxy rotation curve as shown in the figure. The discrepancy between the observed curve (relatively flat) and the curve based upon the known mass of the stars and gas in the Milky Way (decaying curve) is attributed to dark matter.

History

Etymology and beliefs

Main articles: List of names for the Milky Way and Milky Way (mythology)

There are many creation myths around the world which explain the origin of the Milky Way and give it its name. The English phrase is a translation from Ancient Greek , Galaxias, which is derived from the word for milk (, gala). This is also the origin of the word galaxy. In Greek myth, the Milky Way was caused by milk spilt by Hera when suckling Heracles.

In Sanskrit and several other Indo-Aryan languages, the Milky Way is called Akash Ganga (, Ganges of the heavens). The milky way is held to be sacred in the Hindu scriptures known as the Puranas, and the Ganges and the milky way are considered to be terrestrial-celestial analogs of each other. However, the term Kshira (, milk) is also used as an alternative name for the milky way in Hindu texts.

In a large area from Central Asia to Africa, the name for the Milky Way is related to the word for “straw”. This may have originated in ancient Armenian mythology, ( hard goghi chanaparh, or “Trail of the Straw Thief”), and been carried abroad by Arabs. In several Uralic, Turkic languages, Fenno-Ugric languages and in the Baltic languages the Milky Way is called the “Birds’ Path” (Linnunrata in Finnish), since the route of the migratory birds appear to follow the Milky Way. (The Qi Xi legend celebrated in many Asian cultures references a seasonal bridge across the Milky Way formed by birds, usually magpies or crows.) The Chinese name “Silver River” () is used throughout East Asia, including Korea and Japan. An alternative name for the Milky Way in ancient China, especially in poems, is “Heavenly Han River”(). In Japanese, “Silver River” ( ginga) means galaxies in general and the Milky Way is called the “Silver River System” ( gingakei) or the “River of Heaven” ( Amanokawa or Amanogawa). In Swedish, it is called Vintergatan, or “Winter Avenue”, because the stars in the belt were used to predict when winter would arrive.citation needed In some of the Iberian languages, the Milky Way’s name translates as the “Road of Saint James” (e.g., in Spanish it is sometimes called “El camino de Santiago”).

Discovery

See also: Galaxybservation history

The shape of the Milky Way as deduced from star counts by William Herschel in 1785; the Solar System was assumed near center.

Photograph of the “Great Andromeda Nebula” from 1899, later identified as the Andromeda Galaxy.

As Aristotle (384-322 BC) informs us in Meteorologica (DK 59 A80), the Greek philosophers Anaxagoras (ca. 500428 BC) and Democritus (450370 BC) proposed the Milky Way might consist of distant stars. However, Aristotle himself believed the Milky Way to be caused by “the ignition of the fiery exhalation of some stars which were large, numerous and close together” and that the “ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions.” The Arabian astronomer, Alhazen (965-1037 AD), refuted this by making the first attempt at observing and measuring the Milky Way’s parallax, and he thus “determined that because the Milky Way had no parallax, it was very remote from the earth and did not belong to the atmosphere.”

The Persian astronomer, Ab Rayhn al-Brn (973-1048), proposed the Milky Way galaxy to be a collection of countless nebulous stars. Avempace (d. 1138) proposed the Milky Way to be made up of many stars but appears to be a continuous image due to the effect of refraction in the Earth’s atmosphere. Ibn Qayyim Al-Jawziyya (1292-1350) proposed the Milky Way galaxy to be “a myriad of tiny stars packed together in the sphere of the fixed stars” and that that these stars are larger than planets.

Actual proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it was composed of a huge number of faint stars. In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright, speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales. The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Kant also conjectured that some of the nebulae visible in the night sky might be separate “galaxies” themselves, similar to our own.

The first attempt to describe the shape of the Milky Way and the position of the Sun within it was carried out by William Herschel in 1785 by carefully counting the number of stars in different regions of the visible sky. He produced a diagram of the shape of the Galaxy with the Solar System close to the center.

In 1845, Lord Rosse constructed a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae. He also managed to make out individual point sources in some of these nebulae, lending credence to Kant’s earlier conjecture.

In 1917, Heber Curtis had observed the nova S Andromedae within the “Great Andromeda Nebula” (Messier object M31). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within our galaxy. As a result he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the “island universes” hypothesis, which held that the spiral nebulae were actually independent galaxies. In 1920 the Great Debate took place between Harlow Shapley and Heber Curtis, concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the universe. To support his claim that the Great Andromeda Nebula was an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift.

The matter was conclusively settled by Edwin Hubble in the early 1920s using a new telescope. He was able to resolve the outer parts of some spiral nebulae as collections of individual stars and identified some Cepheid variables, thus allowing him to estimate the distance to the nebulae: they were far too distant to be part of the Milky Way. In 1936, Hubble produced a classification system for galaxies that is used to this day, the Hubble sequence.

See also

Astronomy portal

Space portal

Galactic coordinate system

Dark matter halo

Smith’s Cloud

Oort Constants

The Great Rift, a molecular dust cloud located between the solar system and the Sagittarius Arm of the Milky Way which appears to split the Milky Way into two lanes over a third of its length

MilkyWay@Home, a distributed computing project that attempts to generate highly accurate three-dimensional dynamic models of stellar streams in the immediate vicinity of our Milky Way galaxy.

References

a b c Christian, Eric; Samar, Safi-Harb. “How large is the Milky Way?”. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980317b.html. Retrieved 2007-11-28. 

http://www.nasa.gov/worldbook/galaxy_worldbook.html

http://www.scientific-web.com/en/Astronomy/Galaxies/MilkyWay.html

http://www.universetoday.com/guide-to-space/milky-way/how-many-stars-are-in-the-milky-way/

a b Frebel, Anna (2007). “Discovery of HE 1523-0901, a Strongly r-Process-enhanced Metal-poor Star with Detected Uranium”. The Astrophysical Journal 660: L117. doi:10.1086/518122. ariv:astro-ph/0703414. 

a b Bissantz, Nicolai (2003). “Gas dynamics in the Milky Way: second pattern speed and large-scale morphology”. Monthly Notices of the Royal Astronomical Society 340: 949. doi:10.1046/j.1365-8711.2003.06358.x. ariv:astro-ph/0212516. 

a b Kogut, A.; Lineweaver, C.; Smoot, G. F.; Bennett, C. L.; Banday, A.; Boggess, N. W.; Cheng, E. S.; de Amici, G.; Fixsen, D. J.; Hinshaw, G.; Jackson, P. D.; Janssen, M.; Keegstra, P.; Loewenstein, K.; Lubin, P.; Mather, J. C.; Tenorio, L.; Weiss, R.; Wilkinson, D. T.; Wright, E. L. (1993). “Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps”. Astrophysical Journal 419: 1. doi:10.1086/173453. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ApJ…419….1K. Retrieved 2007-05-10. 

Freedman, Roger A.; Kaufmann, William J. (2007). Universe. WH Freeman & Co.. p. 605. ISBN 0-7167-8584-6. 

“Galaxies Milky Way Galaxy”. Encyclopedia Britannica. 19. Encyclopedia Britannica, Inc.. 1998. pp. p. 618. 

Pasachoff, Jay M. (1994). Astronomy: From the Earth to the Universe. Harcourt School. p. 500. ISBN 0-03-001667-3. 

Sanders, Robert (January 9, 2006). “Milky Way Galaxy is warped and vibrating like a drum”. UCBerkeley News. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2006-05-24. 

Frommert, H.; Kronberg, C. (August 25, 2005). “The Milky Way Galaxy”. SEDS. http://www.seds.org/messier/more/mw.html. Retrieved 2007-05-09. 

Young, Kelly (2006-06-06). “Andromeda galaxy hosts a trillion stars”. NewScientist. http://www.newscientist.com/article/dn9282-andromeda-galaxy-hosts-a-trillion-stars.html. Retrieved 2006-06-08. 

http://arxiv.org/abs/0909.3857

“Milky Way fatter than first thought”. The Sydney Morning Herald. Australian Associated Press. 2008-02-20. http://news.smh.com.au/milky-way-fatter-than-first-thought/20080220-1tbv.html. Retrieved 2008-04-24. 

Connors, et al. (2007). “N-body simulations of the Magellanic stream”. Monthly Notices of the Royal Astronomical Society 371: 108. doi:10.1111/j.1365-2966.2006.10659.x. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?bibcode=2006MNRAS.371..108C&db_key=AST&data_type=HTML&format=&high=45a3b56f2301128. Retrieved 2007-01-26. 

“Milky Way a Swifter Spinner, More Massive, New Measurements Show”. 2009-01-05. http://www.nrao.edu/pr/2009/mwrotate/. Retrieved 2009-01-20. 

Ron Cowen (January 5, 2009). “This just in: Milky Way as massive as 3 trillion suns”. Society for Science & the Public. http://www.sciencenews.org/view/generic/id/39709/title/This_just_in_Milky_Way_as_massive_as_3_trillion_suns. Retrieved 2009-01-14. 

Del Peloso, E. F. (2005). “The age of the Galactic thin disk from Th/Eu nucleocosmochronology”. Astronomy and Astrophysics 440: 1153. doi:10.1051/0004-6361:20053307. ariv:astro-ph/0506458. Bibcode: 2005A&A…440.1153D. 

Ortwin, Gerhard (2002). “Mass distribution in our galaxy”. Space Science Reviews 100 (1/4): 129138. doi:10.1023/A:1015818111633. http://adsabs.harvard.edu/abs/2002astro.ph..3110G. Retrieved 2007-03-14. 

Chen, W.; Gehrels, N.; Diehl, R.; Hartmann, D. (1996). “On the spiral arm interpretation of COMPTEL 26Al map features”. Space Science Reviews 120: 315316. http://adsabs.harvard.edu/abs/1996A&AS..120C.315C. Retrieved 2007-03-14. 

McKee, Maggie (August 16, 2005). “Bar at Milky Way’s heart revealed”. New Scientist. http://www.newscientist.com/article/dn7854–bar-at-milky-ways-heart-revealed.html. Retrieved 2009-06-17. 

Karachentsev, I. D.; Kashibadze, O. G. (2006). “Masses of the local group and of the M81 group estimated from distortions in the local velocity field”. Astrophysics 49 (1): 318. doi:10.1007/s10511-006-0002-6. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006Ap…..49….3K. 

Vayntrub, Alina (2000). “Mass of the Milky Way”. The Physics Factbook. http://hypertextbook.com/facts/2000/AlinaVayntrub.shtml. Retrieved 2007-05-09. 

a b Battaglia, G.; Helmi, A.; Morrison, H.; Harding, P.; Olszewski, E. W.; Mateo, M.; Freeman, K. C.; Norris, J.; Shectman, S. A. (2005). “The radial velocity dispersion profile of the Galactic halo: Constraining the density profile of the dark halo of the Milky Way” (abstract). Monthly Notices of the Royal Astronomical Society 364: 433442. http://arxiv.org/abs/astro-ph/0506102. Retrieved 2007-05-09. 

Grant. J.; Lin, B. (2000). “The Stars of the Milky Way”. Fairfax Public Access Corporation. http://members.fcac.org/sol/chview/chv5.htm. Retrieved 2007-05-09. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. pp. 5051. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA50&dq=Milky+Way+%22black+hole%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA51,M1. 

Blandford, R.D. (1999). “Origin and evolution of massive black holes in galactic nuclei”. Galaxy Dynamics, proceedings of a conference held at Rutgers University, 812 Aug 1998,ASP Conference Series vol. 182. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999ASPC..182…87B&db_key=AST&data_type=HTML&format=&high=455327e36328623. 

Staff (September 12, 2005). “Introduction: Galactic Ring Survey”. Boston University. http://www.bu.edu/galacticring/new_introduction.htm. Retrieved 2007-05-10. 

a b Benjamin, R. A. (2008). “The Spiral Structure of the Galaxy: Something Old, Something New…”. in Beuther, H.; Linz, H.; Henning, T. (ed.). Massive Star Formation: Observations Confront Theory. 387. Astronomical Society of the Pacific Conference Series. pp. 375. http://adsabs.harvard.edu/abs/2008ASPC..387..375B. laysource=Space.com Lay summary (2008-06-03). 

See also Bryner, Jeanna (2008-06-03). “New Images: Milky Way Loses Two Arms”. Space.com. http://www.space.com/scienceastronomy/080603-aas-spiral-arms.html. Retrieved 2008-06-04. 

Imamura, Jim (August 10, 2006). “Mass of the Milky Way Galaxy”. University of Oregon. http://zebu.uoregon.edu/imamura/123/lecture-2/mass.html. Retrieved 2007-05-10. 

Harris, William E. (February 2003). “Catalog of Parameters for Milky Way Globular Clusters: The Database” (text). SEDS. http://www.seds.org/messier/xtra/data/mwgc.dat.txt. Retrieved 2007-05-10. 

Ibata, R.; Chapman, S.; Ferguson, A. M. N.; Lewis, G.; Irwin, M.; Tanvir, N. (2005). “On the accretion origin of a vast extended stellar disk around the Andromeda Galaxy”. Astrophysical Journal 634 (1): 287313. doi:10.1086/491727. http://adsabs.harvard.edu/abs/2005ApJ…634..287I. Retrieved 2007-05-10. 

“Outer Disk Ring?”. SolStation. http://www.solstation.com/x-objects/gal-ring.htm. Retrieved 2007-05-10. 

Reid, Mark J. (1993). “The distance to the center of the galaxy”. Annual review of astronomy and astrophysics 31: 345372. doi:10.1146/annurev.aa.31.090193.002021. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ARA%26A..31..345R&amp. Retrieved 2007-05-10. 

Eisenhauer, F.; Schdel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003). “A Geometric Determination of the Distance to the Galactic Center”. The Astrophysical Journal 597: L121124. doi:10.1086/380188. http://adsabs.harvard.edu/abs/2003astro.ph..6220E. Retrieved 2007-05-10. 

Horrobin, M.; Eisenhauer, F.; Tecza, M.; Thatte, N.; Genzel, R.; Abuter, R.; Iserlohe, C.; Schreiber, J.; Schegerer, A.; Lutz, D.; Ott, T.; Schdel, R. (2004). “First results from SPIFFI. I: The Galactic Center” (PDF). Astronomische Nachrichten 325: 120123. doi:10.1002/asna.200310181. http://www.mpe.mpg.de/SPIFFI/preprints/first_result_an1.pdf. Retrieved 2007-05-10. 

Eisenhauer, F. et al. (2005). “SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month”. The Astrophysical Journal 628 (1): 246259. doi:10.1086/430667. http://adsabs.harvard.edu/abs/2005ApJ…628..246E. Retrieved 2007-08-12. 

a b Majaess, D. J.; Turner D. G., Lane D. J. (2009). “Characteristics of the Galaxy according to Cepheids”. MNRAS 398: 263 - 270. doi:10.1111/j.1365-2966.2009.15096.x. http://adsabs.harvard.edu/abs/2009arXiv0903.4206M. 

English, Jayanne (1991-07-24). “Exposing the Stuff Between the Stars”. Hubble News Desk. http://www.ras.ucalgary.ca/CGPS/press/aas00/pr/pr_14012000/pr_14012000map1.html. Retrieved 2007-05-10. 

Gillman, M. and Erenler, H. (2008). “The galactic cycle of extinction”. International Journal of Astrobiology 7. doi:10.1017/S1473550408004047. http://journals.cambridge.org/action/displayAbstract?aid=1804088. Retrieved 2008-04-11. 

Leong, Stacy (2002). “Period of the Sun’s Orbit around the Galaxy (Cosmic Year)”. The Physics Factbook. http://hypertextbook.com/facts/2002/StacyLeong.shtml. Retrieved 2007-05-10. 

Garlick, Mark Antony (2002). The Story of the Solar System. Cambridge University. p. 46. ISBN 0521803365. 

University of California, Berkeley (2006-01-09). “Milky Way galaxy is warped and vibrating like a drum”. Press release. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2007-10-18. 

Wong, Janet (April 14, 2000). “Astrophysicist maps out our own galaxy’s end”. University of Toronto. http://www.news.utoronto.ca/bin/000414b.asp. Retrieved 2007-01-11. 

Peter Schneider (2006). Extragalactic Astronomy and Cosmology. Springer. p. 4, Figure 1.4. ISBN 3540331743. http://books.google.com/books?id=uP1Hz-6sHaMC&pg=PA100&dq=rotation+Milky+way&lr=&as_brr=0&as_pt=ALLTYPES#PPA5,M1. 

Theo Koupelis, Karl F Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. p. 492; Figure 16-13. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 21; Figure 1.13. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA20&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA21,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 298. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA4&dq=movement+%22Milky+Way%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA298,M1. 

Peirani, S (2006). “Mass determination of groups of galaxies: Effects of the cosmological constant”. New Astronomy 11: 325. doi:10.1016/j.newast.2005.08.008. 

Theo Koupelis, Karl F. Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. pp. 492, Figure 1613. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22+date:2004-2010&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

a b A M T Jackson, R.E. Enthoven (1989), Folk Lore Notes, Asian Educational Services, ISBN 8120604857, http://books.google.com/books?id=eRkuXFD93zsC, “… According to the Puranas, the milky way or akashganga is the celestial River Ganga which was brought down by Bhagirath …” 

Hormusjee Shapoorjee Spencer (1965), The Aryan ecliptic cycle: glimpses into ancient Indo-Iranian religious history from 25628 B.C. to 292 A.D., H.P. Vaswani, http://books.google.com/books?id=jdMoAAAAYAAJ, “… There are two “Gangas” one terrestrial and the other “akashic” or celestial … bear reference only to the “Akash Ganga” which is the Milky Way …” 

Edward C. Sachau (2001), Alberuni’s India: an account of the religion, philosophy, literature, geography, chronology, astronomy, customs, laws and astrology of India about A.D. 1030, Routledge, http://books.google.com/books?id=a91-t4uw8A4C, “… revolves around Kshira, i.e. the Milky Way …” 

Harutyunyan, Hayk (2003-08-29). “The Armenian name of the Milky Way” (dead link Scholar search). ArAS News (Armenian Astronomical Society (ArAS)) 6. http://www.aras.am/ARASNEWS/arasnews06.html. Retrieved 2007-01-05. 

a b Josep Puig Montada (September 28, 2007). “Ibn Bajja”. Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/ibn-bajja. Retrieved 2008-07-11. 

Mohamed, Mohaini (2000), Great Muslim Mathematicians, Penerbit UTM, pp. 4950, ISBN 9835201579 

Hamid-Eddine Bouali, Mourad Zghal, Zohra Ben Lakhdar (2005). “Popularisation of Optical Phenomena: Establishing the First Ibn Al-Haytham Workshop on Photography” (PDF). The Education and Training in Optics and Photonics Conference. http://spie.org/etop/ETOP2005_080.pdf. Retrieved 2008-07-08. 

O’Connor, John J.; Robertson, Edmund F., “Abu Rayhan Muhammad ibn Ahmad al-Biruni”, MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Biruni.html .

Livingston, John W. (1971), “Ibn Qayyim al-Jawziyyah: A Fourteenth Century Defense against Astrological Divination and Alchemical Transmutation”, Journal of the American Oriental Society 91 (1): 96103 , doi:10.2307/600445 

O’Connor, J. J.; Robertson, E. F. (November 2002). “Galileo Galilei”. University of St Andrews. http://www-gap.dcs.st-and.ac.uk/history/Biographies/Galileo.html. Retrieved 2007-01-08. 

Evans, J. C. (November 24 1998). “Our Galaxy”. George Mason University. http://physics.gmu.edu/jevans/astr103/CourseNotes/ECText/ch20_txt.htm. Retrieved 2007-01-04. 

Abbey, Lenny. “The Earl of Rosse and the Leviathan of Parsontown”. The Compleat Amateur Astronomer. http://labbey.com/Telescopes/Parsontown.html. Retrieved 2007-01-04. 

Heber D. Curtis (1988). “Novae in Spiral Nebulae and the Island Universe Theory”. Publications of the Astronomical Society of the Pacific 100: 6. doi:10.1086/132128. http://adsabs.harvard.edu/abs/1988PASP..100….6C. 

Weaver, Harold F.. “Robert Julius Trumpler”. National Academy of Sciences. http://www.nap.edu/readingroom/books/biomems/rtrumpler.html. Retrieved 2007-01-05. 

Hubble, E. P. (1929). “A spiral nebula as a stellar system, Messier 31″. Astrophysical Journal 69: 103158. doi:10.1086/143167. http://adsabs.harvard.edu/cgi-bin/bib_query?1929ApJ….69..103H. 

Sandage, Allan (1989). “Edwin Hubble, 18891953″. The Journal of the Royal Astronomical Society of Canada 83 (6). http://antwrp.gsfc.nasa.gov/diamond_jubilee/1996/sandage_hubble.html. Retrieved 2007-01-08. 

Further reading

Thorsten Dambeck in Sky and Telescope, “Gaia’s Mission to the Milky Way”, March 2008, p. 3639.

External links

Wikimedia Commons has media related to: Milky Way Galaxy

The Milky Way Galaxy from An Atlas of the Universe

A 3D map of the Milky Way Galaxy

Chromoscope Tools to Explore the known Milky Way

Milky Way IRAS (infrared) survey wikisky.org

Milky Way H-Alpha survey wikisky.org

Interactive full screen Silverlight map of the Milky Way

Running Rings Around the Galaxy Spitzer Space Telescope News

The Milky Way Galaxy, SEDS Messier pages

MultiWavelength Milky Way, NASA site with images and VRML models

Milky Way Explorer, detailed images in infrared with radio, microwave and hydrogen-alpha as well

Face-on Milky Way maps, within about 10 thousand parsecs

The Milky Way at the Astro-Photography Site Of Mister T. Yoshida.

Widefield Image of the Summer Milky Way

Proposed Ring around the Milky Way

Milky Way spiral gets an extra arm, New Scientist.com

Possible New Milky Way Spiral Arm, Sky and Telescope.com

The Milky Way spiral arms and a possible climate connection

Galactic center mosaic via sun-orbiting Spitzer infrared telescope

Milky Way Plan Views, The University of Calgary Radio Astronomy Laboratory

Our Growing, Breathing Galaxy, Scientific American Magazine (January 2004 Issue)

Deriving The Shape Of The Galactic Stellar Disc, SkyNightly (March 17, 2006)

Digital Sky LLC, Digital Sky’s Milky Way Panorama and other images

A new view of the Milky Way galaxy obtained by the Diffuse Infrared Background Experiment (DIRBE) on NASA’s Cosmic Background Explorer satellite (COBE).

Image of Milky Way galaxy arms, Chandra X-ray Observatory Center

The 1920 Shapley Curtis Debate on the size of the Milky Way

Milky Way Voyage India’s First & Largest Star Party

Astronomy Picture of the Day:

Composite image of the Milky Way

Milky Way Illustrated

Barred Spiral Milky Way (Illustrated)

Radioactive Clouds in the Milky Way

Milky Way Molecule Map

The Milky Way’s Gamma-Ray Halo

Moving Milkyway seen from Teneriffe without any lightpollution

Multi-Gigapixel Infrared Milky Way A zoomable, annotated version of the Spitzer Space Telescope GLIMPSE survey.

Animated tour of the Milky Way, University of Glamorgan

v  d  e

The Milky Way

Location

Universe  Virgo Supercluster  Local Group

Galactic core

Center of the Milky Way

Spiral arms

Sagittarius-Carina  Scutum-Crux  Norma-Cygnus  Perseus  Orion

Satellite galaxies

Magellanic Clouds

Large Magellanic Cloud  Small Magellanic Cloud  Magellanic Stream  Magellanic Bridge

Sagittarius Elliptical

Sagittarius Stream   Botes II  Coma Berenices  Messier 54  Palomar 12  Segue 1  Segue 2  Terzan 7

Dwarves

Botes I  Botes III  Canes Venatici I  Canes Venatici II  Canis Major  Carina  Draco  Fornax  Hercules  Leo I  Leo II  Leo IV  Leo V  Phoenix  Sculptor  Sextans Spheroidal  Ursa Major I  Ursa Major II  Ursa Minor

Other

Monoceros Ring  Virgo Stream  Willman 1

v  d  e

Earth’s location in the universe

Earth  Solar System  Local Interstellar Cloud  Local Bubble  Gould Belt  Orion Arm  Milky Way  Milky Way subgroup  Local Group  Local Supercluster  Pisces-Cetus Supercluster Complex  Large-scale structure of the cosmos  Observable universe  Universe

Each arrow should be read as “within” or “part of”.

Categories: Milky Way Galaxy Milky Way Subgroup Local Group Galactic astronomy Barred spiral galaxies Spiral galaxiesHidden categories: All articles with dead external links Articles with dead external links from April 2009 Wikipedia indefinitely move-protected pages All articles with unsourced statements Articles with unsourced statements from October 2009 Articles with unsourced statements from September 2008 Articles with unsourced statements from August 2008

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 Without a doubt, each business service provider is unique. National business Quality Management programs ought to be designed to handle the particular wants of individual business service providers. All official Quality Management programs typically have these two universal parts:

1. Quality Management policy statement of the aims of the chance management program and therefore the responsibilities for safety, security, quality and compliance

2. Regularly scheduled audits and inspections of premises, tools, and work practices

In this text, we have a tendency to can discuss Quality Management Policy and Audits parts of a good Quality Management Program. Many

1. Safety policy

Every basic risk management program, whether it is Quality Management or Environmental Management, needs a statement of the employers aims and also the obligations of the employer, supervisors, and workers. This statement, usually called an Quality Management policy, sometimes states:

* The employers (CEO, top management) dedication to the Quality Management program

* The employers commitment to protect the safety of employees and all stakeholders

* The goals and priorities of the business service provider’s Quality Management program

* The duties and obligations of the employer, supervisors, and employees

Successful safety policies ought to be merely written and easy to understand. They are doing not would like to be longer than some paragraphs. The written Quality Management policy should be signed by the CEO or most senior manager, whatever his title could be. It should be dated and reviewed annually. All employees ought to be created conscious of the policy and its importance. For instance, it may be given to all or any new employees and posted within the workplace, or on the business service supplier’s Internet site.

2. Recurrent audits and inspections

Normal audits and inspections of the workplace are meant to:

* Determine conditions and unsafe acts with the possibility to cause injury or injury to equipment

* Verify obligatory corrective measures

* Prevent unsafe working conditions from developing

Three different kinds of audits and inspections are defined below:

Regular, planned workplace audits and inspections: Examine buildings, structures, grounds, aircraft, tools, equipment, machinery, and work methods and practices for hazards that might cause injury or injury to aircraft or the surroundings. Schedule these audits and inspections at acceptable intervals to prevent unsafe circumstances developing. Relying on the business service provider and the sort of hazards that may develop, audits and inspections could be scheduled daily, weekly, or monthly.

Equipment audits and inspections: Workers ought to be trained to inspect their machinery, tools, and equipment frequently, following the manufacturers minimum recommendations. National regulatory agencies might also have specific requirements.

Special audits and inspections: National regulatory agencies typically require special inspections or audits after certain types of events to confirm that operations do not resume until it is safe to do so.

Business service providers audits and inspections

Quality Management inspection groups usually include both worker and management representatives. Terribly typically, a third-party auditor regularly conducts these audits and inspections. Quality Management auditing groups should be familiar with the work flow process and, whenever doable, include members of the joint safety committee or the company’s safety delegate.

Inspection checklists can facilitate guarantee that audits and inspections are thorough, results are recorded, and therefore the inspection method is standardized. A checklist is notably useful in guiding those unfamiliar with the inspection process. Checklists ought to be adapted to suit the requirements of every business service provider’s unique activities.

Every unsafe or harmful conditions found during a regular inspection or audit should be reported right away to the supervisor or employer and remedied while not delay.

Document and write all important findings for future reference. Each hazard discovered should be recorded and also the corrective actions taken to eliminate or control every hazard. Guarantee to speak this info to the joint safety committee for his or her review and approval.

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Milky Way

By w3hbre

 Appearance from Earth

The Milky Way Galaxy, as viewed from Earth’s position in a spur of one of the galaxy’s spiral arms (see Sun’s location and neighborhood), appears as a hazy band of white light in the night sky arching across the entire celestial sphere. The light originates from stars and other material that lie within the galactic plane. The plane of the Milky Way is inclined by about 60 to the ecliptic (the plane of the Earth’s orbit), with the North Galactic Pole situated at right ascension 12h 49m, declination +27.4 (B1950) near beta Comae Berenices. The South Galactic Pole is near alpha Sculptoris.

The center of the galaxy lies in the direction of Sagittarius, and it is here that Milky Way looks brightest. Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth’s equatorial plane and the plane of the ecliptic relative to the galactic plane. From Sagittarius, the Milky Way appears to pass westward through the constellations of Scorpius, Ara, Norma, Triangulum Australe, Circinus, Centaurus, Musca, Crux, Carina, Vela, Puppis, Canis Major, Monoceros, Orion & Gemini, Taurus, Auriga, Perseus, Andromeda, Cassiopeia, Cepheus & Lacerta, Cygnus, Vulpecula, Sagitta, Aquila, Ophiuchus, Scutum, and back to Sagittarius. The fact that the Milky Way divides the night sky into two roughly equal hemispheres indicates that the Solar System lies close to the galactic plane. The Milky Way has a relatively low surface brightness due to the interstellar medium that fills the galactic disk, and preventing us from seeing the bright galactic center. It is thus difficult to see from any urban or suburban location suffering from light pollution.

Panoramas

360-degree photographic panorama of the galaxy.

A panorama of the Milky Way, as seen from Death Valley, 2005.

The plane of our Milky Way Galaxy, which we see edge-on from our perspective on Earth, cuts a luminous swath across the image. Credit: ESO/S. Brunier

The Milky Way arches across this rare 360-degree panorama of the night sky above the Paranal platform, home of ESO Very Large Telescope. The image was made from 37 individual frames with a total exposure time of about 30 minutes, taken in the early morning hours. The Moon is just rising and the zodiacal light shines above it, while the Milky Way stretches across the sky opposite the observatory. Credit: ESO/H. Heyer

Size

The Galactic Plane seen by the ATLASGAL survey, divided into sections. Credit ESO.

The stellar disk of the Milky Way Galaxy is approximately 100,000 light-years (91017 km) (61017 mi) in diameter, and is considered to be, on average, about 1,000 ly (91015 km) thick. It is estimated to contain at least 200 billion stars and possibly up to 400 billion stars, the exact figure depending on the number of very low-mass stars, which is highly uncertain. This can be compared to the one trillion (1012) stars of the neighbouring Andromeda Galaxy. The stellar disc does not have a sharp edge, a radius beyond which there are no stars. Rather, the number of stars drops smoothly with distance from the centre of the Galaxy. Beyond a radius of roughly 40,000 light-years (41017 km) the number of stars drops much faster with radius , for reasons that are not understood.

Extending beyond the stellar disk is a much thicker disk of gas. Recent observations indicate that the gaseous disk of the Milky Way has a thickness of around 12,000 ly (11017 km)wice the previously accepted value. As a guide to the relative physical scale of the Milky Way, if it were reduced to 10m in diameter, the Solar System, including the hypothesized Oort cloud, would be no more than 0.1mm in width.

The Galactic Halo extends outward, but is limited in size by the orbits of two Milky Way satellites, the Large and the Small Magellanic Clouds, whose perigalacticon is at 180,000 ly (21018 km). At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds, and the objects would likely be ejected from the vicinity of the Milky Way.

Recent measurements by the Very Long Baseline Array (VLBA) have revealed that the Milky Way is much more massive than some previously thought. The mass of our home galaxy is now considered to be roughly similar to that of our largest local neighbour, the Andromeda Galaxy. By using the VLBA to measure the apparent shift or parallax of far-flung star-forming regions when the Earth is on opposite sides of the Sun, the researchers were able to measure the distance to those regions using fewer assumptions than prior efforts. The newer and more accurate estimate of the galaxy’s rotational speed (and in turn the amount of dark matter contained by the galaxy) is about 254 km/s, significantly higher than the widely accepted value of 220 km/s. This in turn implies that the Milky Way has a total mass of approximately 3 trillion solar masses, about 50% more massive than previously thought.

Age

Main articles: Galaxy formation and evolution and nucleocosmochronology

A green and red Perseid meteor streaks across the sky just below the Milky Way in August 2007.

As of 2004, the age of the oldest star in the galaxy yet discovered, HE 1523-0901, is estimated to be about 13.2 billion years, nearly as old as the Universe. This estimate was determined using the UV-Visual Echelle Spectrograph of the Very Large Telescope to measure the beryllium content of two stars in globular cluster NGC 6397.citation needed The elapsed time between the rise of the first generation of stars in the Milky Way and the first generation of stars in the cluster was deduced to be 200 million to 300 million years. By including the estimated age of the stars in the globular cluster, 13.4 0.8 billion years, the estimated age of the oldest stars in the Milky Way is 13.6 0.8 billion years. The Galactic thin disk is estimated to have been formed between 6.5 and 10.1 billion years ago.

Composition and structure

The galactic center in the direction of Sagittarius. The primary stars of Sagittarius are indicated in red.

The galaxy consists of a bar-shaped core region surrounded by a disk of gas, dust and stars forming four distinct arm structures spiralling outward in a logarithmic spiral shape (see Spiral arms). The mass distribution within the galaxy closely resembles the Sbc Hubble classification, which is a spiral galaxy with relatively loosely-wound arms. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1990s. Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 which showed the galaxy’s central bar to be larger than previously suspected.

The Milky Way’s mass is thought to be about 5.8  1011 solar masses (M) comprising 200 to 400 billion stars. Its integrated absolute visual magnitude has been estimated to be 20.9. Most of the mass of the galaxy is thought to be dark matter, forming a dark matter halo of an estimated 6003000 billion M which is spread out relatively uniformly.

Galactic Center

Main article: Galactic Center

Observed structure of the Milky Way’s spiral arms. Our Sun is in the Local Spur.

The galactic disc, which bulges outward at the galactic center, has a diameter of between 70,000 and 100,000 light-years. The distance from the Sun to the galactic center is now estimated at 26,000 1400 light-years, while older estimates could put the Sun as far as 35,000 light-years from the central bulge.

The galactic center harbors a compact object of very large mass as determined by the motion of material around the center. The intense radio source named Sagittarius A*, thought to mark the center of the Milky Way, is newly confirmed to be a supermassive black hole. For a photo see Chandra X-ray Observatory; Jan. 6, 2003. Most galaxies are believed to have a supermassive black hole at their center.

The galaxy’s bar is thought to be about 27,000 light-years long, running through its center at a 44 10 degree angle to the line between the Sun and the center of the galaxy. It is composed primarily of red stars, believed to be ancient (see red dwarf, red giant). The bar is surrounded by a ring called the “5-kpc ring” that contains a large fraction of the molecular hydrogen present in the galaxy, as well as most of the Milky Way’s star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of our own galaxy.

Spiral arms

Observed and extrapolated structure of the spiral arms.

Artist’s conception of the spiral structure of the Milky Way with two major stellar arms and a bar.

Each spiral arm describes a logarithmic spiral (as do the arms of all spiral galaxies) with a pitch of approximately 12 degrees. Until recently, there were believed to be four major spiral arms which all start near the galaxy’s center. These are named as follows, according to the image at right:

Color

Arm(s)

cyan

3-kpc and Perseus Arm

purple

Norma and Outer arm (Along with a newly discovered extension)

green

Scutum-Crux Arm

pink

Carina and Sagittarius Arm

There are at least two smaller arms or spurs, including:

orange

Orion-Cygnus arm (which contains the Sun and Solar System)

Observations presented in 2008 by Robert Benjamin of the University of Wisconsin-Whitewater suggest that the Milky Way possesses only two major stellar arms: the Perseus arm and the Scutum-Centaurus arm. The rest of the arms are minor or adjunct arms. This would mean that the Milky Way is similar in appearance to NGC 1365.

Outside of the major spiral arms is the Monoceros Ring (or Outer Ring), proposed by astronomers Brian Yanny and Heidi Jo Newberg, a ring of gas and stars torn from other galaxies billions of years ago.

As is typical for many galaxies, the distribution of mass in the Milky Way Galaxy is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike the situation within the Solar System, where two-body gravitational dynamics dominate and different orbits are expected to have significantly different velocities associated with them. This difference is one of the major pieces of evidence for the existence of dark matter. Another interesting aspect is the so-called “wind-up problem” of the spiral arms. If the inner parts of the arms rotate faster than the outer part, then the galaxy will wind up so much that the spiral structure will be thinned out. But this is not what is observed in spiral galaxies; instead, astronomers propose that the spiral pattern is a density wave emanating from the galactic center. This can be likened to a moving traffic jam on a highway the cars are all moving, but there is always a region of slow-moving cars. This model also agrees with enhanced star formation in or near spiral arms; the compressional waves increase the density of molecular hydrogen and protostars form as a result.

Halo

The galactic disk is surrounded by a spheroid halo of old stars and globular clusters, of which 90% lie within 100,000 light-years, suggesting a stellar halo diameter of 200,000 light-years. However, a few globular clusters have been found farther, such as PAL 4 and AM1 at more than 200,000 light-years away from the galactic center. While the disk contains gas and dust which obscure the view in some wavelengths, the spheroid component does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but not in the halo. Open clusters also occur primarily in the disk.

Recent discoveries have added dimension to the knowledge of the Milky Way’s structure. With the discovery that the disc of the Andromeda Galaxy (M31) extends much further than previously thought, the possibility of the disk of our own galaxy extending further is apparent, and this is supported by evidence of the newly discovered Outer Arm extension of the Cygnus Arm. With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, it was found that a ring of galactic debris from its interaction with the Milky Way encircles the galactic disk.

On January 9, 2006, Mario Juri and others of Princeton University announced that the Sloan Digital Sky Survey of the northern sky found a huge and diffuse structure (spread out across an area around 5,000 times the size of a full moon) within the Milky Way that does not seem to fit within current models. The collection of stars rises close to perpendicular to the plane of the spiral arms of the galaxy. The proposed likely interpretation is that a dwarf galaxy is merging with the Milky Way. This galaxy is tentatively named the Virgo Stellar Stream and is found in the direction of Virgo about 30,000 light-years away.

Sun’s location and neighborhood

The Sun (and therefore the Earth and the Solar System) may be found close to the inner rim of the galaxy’s Orion Arm, in the Local Fluff inside the Local Bubble, and in the Gould Belt, at a distance of 7.620.32 kpc (25,0001,000 ly) from the Galactic Center. The Sun is currently 530 parsecs from the central plane of the galactic disc. The distance between the local arm and the next arm out, the Perseus Arm, is about 6,500 light-years. The Sun, and thus the Solar System, is found in the galactic habitable zone.

There are about 208 stars brighter than absolute magnitude 8.5 within 15 parsecs of the Sun, giving a density of 0.0147 such stars per cubic parsec, or 0.000424 per cubic light-year (from List of nearest bright stars). On the other hand, there are 64 known stars (of any magnitude, not counting 4 brown dwarfs) within 5 parsecs of the Sun, giving a density of 0.122 stars per cubic parsec, or 0.00352 per cubic light-year (from List of nearest stars), illustrating the fact that most stars are less bright than absolute magnitude 8.5.

The Apex of the Sun’s Way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun’s galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun’s orbit around the Galaxy is expected to be roughly elliptical with the addition of perturbations due to the galactic spiral arms and non-uniform mass distributions. In addition, the Sun oscillates up and down relative to the galactic plane approximately 2.7 times per orbit. This is very similar to how a simple harmonic oscillator works with no drag force (damping) term. These oscillations often coincide with mass extinction periods on Earth; presumably the higher density of stars close to the galactic plane leads to more impact events.

It takes the Solar System about 225250 million years to complete one orbit of the galaxy (a galactic year), so it is thought to have completed 2025 orbits during the lifetime of the Sun and 1/1250 of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Galaxy is approximately 220 km/s. At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit).

A diagram of our location in the Local Supercluster. Click to view more detail.

Environment

Main articles: Local group and Andromeda-Milky Way collision

Broad infrared view of our Milky Way Galaxy from the Spitzer Space Telescope created from more than 800,000 frames. This is the most detailed infrared picture of our galaxy to date.

Milky way starscape taken from Paranal.

Location of the starscape in relation to the rest of the galaxy.

The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, itself being part of the Virgo Supercluster.

Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 20,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a peculiar streamer of neutral hydrogen gas connecting these two small galaxies. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way. Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest Milky Way dwarf galaxies are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies, which are dynamically bound to the Milky Way, as well as some that have already been absorbed by the Milky Way, such as Omega Centauri. Observations through the zone of avoidance are frequently detecting new distant and nearby galaxies. Some galaxies consisting mostly of gas and dust may also have evaded detection so far.

In January 2006, researchers reported that the heretofore unexplained warp in the disk of the Milky Way has now been mapped and found to be a ripple or vibration set up by the Large and Small Magellanic Clouds as they circle the Galaxy, causing vibrations at certain frequencies when they pass through its edges. Previously, these two galaxies, at around 2% of the mass of the Milky Way, were considered too small to influence the Milky Way. However, by taking into account dark matter, the movement of these two galaxies creates a wake that influences the larger Milky Way. Taking dark matter into account results in an approximately twenty-fold increase in mass for the Galaxy. This calculation is according to a computer model made by Martin Weinberg of the University of Massachusetts, Amherst. In this model, the dark matter is spreading out from the galactic disc with the known gas layer. As a result, the model predicts that the gravitational effect of the Magellanic Clouds is amplified as they pass through the Galaxy.

Current measurements suggest the Andromeda Galaxy is approaching us at 100 to 140 kilometers per second. The Milky Way may collide with it in 3 to 4 billion years, depending on the importance of unknown lateral components to the galaxies’ relative motion. If they collide, individual stars within the galaxies would not collide, but instead the two galaxies will merge to form a single elliptical galaxy over the course of about a billion years.

Velocity

Galaxy rotation curve for the Milky Way. Vertical axis is speed of rotation about the galactic center. Horizontal axis is distance from the galactic center in kpcs. The sun is marked with a yellow ball. The observed curve of speed of rotation is blue. The predicted curve based upon stellar mass and gas in the Milky Way is red. Scatter in observations roughly indicated by gray bars. The difference is due to dark matter or perhaps a modification of the law of gravity.

In the general sense, the absolute velocity of any object through space is not a meaningful question according to Einstein’s special theory of relativity, which declares that there is no “preferred” inertial frame of reference in space with which to compare the object’s motion. (Motion must always be specified with respect to another object.) This must be kept in mind when discussing the Galaxy’s motion.

Astronomers believe the Milky Way is moving at approximately 630 km per second relative to the local co-moving frame of reference that moves with the Hubble flow. If the Galaxy is moving at 600 km/s, Earth travels 51.84 million km per day, or more than 18.9 billion km per year, about 4.5 times its closest distance from Pluto. The Milky Way is thought to be moving in the direction of the Great Attractor. The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda galaxy) is part of a supercluster called the Local Supercluster, centered near the Virgo Cluster: although they are moving away from each other at 967 km/s as part of the Hubble flow, the velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.

Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at around 552 km/s with respect to the photons of the CMB, toward 10.5 right ascension, -24 declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction.citation needed

The galaxy rotates about its center according to its galaxy rotation curve as shown in the figure. The discrepancy between the observed curve (relatively flat) and the curve based upon the known mass of the stars and gas in the Milky Way (decaying curve) is attributed to dark matter.

History

Etymology and beliefs

Main articles: List of names for the Milky Way and Milky Way (mythology)

There are many creation myths around the world which explain the origin of the Milky Way and give it its name. The English phrase is a translation from Ancient Greek , Galaxias, which is derived from the word for milk (, gala). This is also the origin of the word galaxy. In Greek myth, the Milky Way was caused by milk spilt by Hera when suckling Heracles.

In Sanskrit and several other Indo-Aryan languages, the Milky Way is called Akash Ganga (, Ganges of the heavens). The milky way is held to be sacred in the Hindu scriptures known as the Puranas, and the Ganges and the milky way are considered to be terrestrial-celestial analogs of each other. However, the term Kshira (, milk) is also used as an alternative name for the milky way in Hindu texts.

In a large area from Central Asia to Africa, the name for the Milky Way is related to the word for “straw”. This may have originated in ancient Armenian mythology, ( hard goghi chanaparh, or “Trail of the Straw Thief”), and been carried abroad by Arabs. In several Uralic, Turkic languages, Fenno-Ugric languages and in the Baltic languages the Milky Way is called the “Birds’ Path” (Linnunrata in Finnish), since the route of the migratory birds appear to follow the Milky Way. (The Qi Xi legend celebrated in many Asian cultures references a seasonal bridge across the Milky Way formed by birds, usually magpies or crows.) The Chinese name “Silver River” () is used throughout East Asia, including Korea and Japan. An alternative name for the Milky Way in ancient China, especially in poems, is “Heavenly Han River”(). In Japanese, “Silver River” ( ginga) means galaxies in general and the Milky Way is called the “Silver River System” ( gingakei) or the “River of Heaven” ( Amanokawa or Amanogawa). In Swedish, it is called Vintergatan, or “Winter Avenue”, because the stars in the belt were used to predict when winter would arrive.citation needed In some of the Iberian languages, the Milky Way’s name translates as the “Road of Saint James” (e.g., in Spanish it is sometimes called “El camino de Santiago”).

Discovery

See also: Galaxybservation history

The shape of the Milky Way as deduced from star counts by William Herschel in 1785; the Solar System was assumed near center.

Photograph of the “Great Andromeda Nebula” from 1899, later identified as the Andromeda Galaxy.

As Aristotle (384-322 BC) informs us in Meteorologica (DK 59 A80), the Greek philosophers Anaxagoras (ca. 500428 BC) and Democritus (450370 BC) proposed the Milky Way might consist of distant stars. However, Aristotle himself believed the Milky Way to be caused by “the ignition of the fiery exhalation of some stars which were large, numerous and close together” and that the “ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions.” The Arabian astronomer, Alhazen (965-1037 AD), refuted this by making the first attempt at observing and measuring the Milky Way’s parallax, and he thus “determined that because the Milky Way had no parallax, it was very remote from the earth and did not belong to the atmosphere.”

The Persian astronomer, Ab Rayhn al-Brn (973-1048), proposed the Milky Way galaxy to be a collection of countless nebulous stars. Avempace (d. 1138) proposed the Milky Way to be made up of many stars but appears to be a continuous image due to the effect of refraction in the Earth’s atmosphere. Ibn Qayyim Al-Jawziyya (1292-1350) proposed the Milky Way galaxy to be “a myriad of tiny stars packed together in the sphere of the fixed stars” and that that these stars are larger than planets.

Actual proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it was composed of a huge number of faint stars. In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright, speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales. The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Kant also conjectured that some of the nebulae visible in the night sky might be separate “galaxies” themselves, similar to our own.

The first attempt to describe the shape of the Milky Way and the position of the Sun within it was carried out by William Herschel in 1785 by carefully counting the number of stars in different regions of the visible sky. He produced a diagram of the shape of the Galaxy with the Solar System close to the center.

In 1845, Lord Rosse constructed a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae. He also managed to make out individual point sources in some of these nebulae, lending credence to Kant’s earlier conjecture.

In 1917, Heber Curtis had observed the nova S Andromedae within the “Great Andromeda Nebula” (Messier object M31). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within our galaxy. As a result he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the “island universes” hypothesis, which held that the spiral nebulae were actually independent galaxies. In 1920 the Great Debate took place between Harlow Shapley and Heber Curtis, concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the universe. To support his claim that the Great Andromeda Nebula was an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift.

The matter was conclusively settled by Edwin Hubble in the early 1920s using a new telescope. He was able to resolve the outer parts of some spiral nebulae as collections of individual stars and identified some Cepheid variables, thus allowing him to estimate the distance to the nebulae: they were far too distant to be part of the Milky Way. In 1936, Hubble produced a classification system for galaxies that is used to this day, the Hubble sequence.

See also

Astronomy portal

Space portal

Galactic coordinate system

Dark matter halo

Smith’s Cloud

Oort Constants

The Great Rift, a molecular dust cloud located between the solar system and the Sagittarius Arm of the Milky Way which appears to split the Milky Way into two lanes over a third of its length

MilkyWay@Home, a distributed computing project that attempts to generate highly accurate three-dimensional dynamic models of stellar streams in the immediate vicinity of our Milky Way galaxy.

References

a b c Christian, Eric; Samar, Safi-Harb. “How large is the Milky Way?”. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980317b.html. Retrieved 2007-11-28. 

http://www.nasa.gov/worldbook/galaxy_worldbook.html

http://www.scientific-web.com/en/Astronomy/Galaxies/MilkyWay.html

http://www.universetoday.com/guide-to-space/milky-way/how-many-stars-are-in-the-milky-way/

a b Frebel, Anna (2007). “Discovery of HE 1523-0901, a Strongly r-Process-enhanced Metal-poor Star with Detected Uranium”. The Astrophysical Journal 660: L117. doi:10.1086/518122. ariv:astro-ph/0703414. 

a b Bissantz, Nicolai (2003). “Gas dynamics in the Milky Way: second pattern speed and large-scale morphology”. Monthly Notices of the Royal Astronomical Society 340: 949. doi:10.1046/j.1365-8711.2003.06358.x. ariv:astro-ph/0212516. 

a b Kogut, A.; Lineweaver, C.; Smoot, G. F.; Bennett, C. L.; Banday, A.; Boggess, N. W.; Cheng, E. S.; de Amici, G.; Fixsen, D. J.; Hinshaw, G.; Jackson, P. D.; Janssen, M.; Keegstra, P.; Loewenstein, K.; Lubin, P.; Mather, J. C.; Tenorio, L.; Weiss, R.; Wilkinson, D. T.; Wright, E. L. (1993). “Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps”. Astrophysical Journal 419: 1. doi:10.1086/173453. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ApJ…419….1K. Retrieved 2007-05-10. 

Freedman, Roger A.; Kaufmann, William J. (2007). Universe. WH Freeman & Co.. p. 605. ISBN 0-7167-8584-6. 

“Galaxies Milky Way Galaxy”. Encyclopedia Britannica. 19. Encyclopedia Britannica, Inc.. 1998. pp. p. 618. 

Pasachoff, Jay M. (1994). Astronomy: From the Earth to the Universe. Harcourt School. p. 500. ISBN 0-03-001667-3. 

Sanders, Robert (January 9, 2006). “Milky Way Galaxy is warped and vibrating like a drum”. UCBerkeley News. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2006-05-24. 

Frommert, H.; Kronberg, C. (August 25, 2005). “The Milky Way Galaxy”. SEDS. http://www.seds.org/messier/more/mw.html. Retrieved 2007-05-09. 

Young, Kelly (2006-06-06). “Andromeda galaxy hosts a trillion stars”. NewScientist. http://www.newscientist.com/article/dn9282-andromeda-galaxy-hosts-a-trillion-stars.html. Retrieved 2006-06-08. 

http://arxiv.org/abs/0909.3857

“Milky Way fatter than first thought”. The Sydney Morning Herald. Australian Associated Press. 2008-02-20. http://news.smh.com.au/milky-way-fatter-than-first-thought/20080220-1tbv.html. Retrieved 2008-04-24. 

Connors, et al. (2007). “N-body simulations of the Magellanic stream”. Monthly Notices of the Royal Astronomical Society 371: 108. doi:10.1111/j.1365-2966.2006.10659.x. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?bibcode=2006MNRAS.371..108C&db_key=AST&data_type=HTML&format=&high=45a3b56f2301128. Retrieved 2007-01-26. 

“Milky Way a Swifter Spinner, More Massive, New Measurements Show”. 2009-01-05. http://www.nrao.edu/pr/2009/mwrotate/. Retrieved 2009-01-20. 

Ron Cowen (January 5, 2009). “This just in: Milky Way as massive as 3 trillion suns”. Society for Science & the Public. http://www.sciencenews.org/view/generic/id/39709/title/This_just_in_Milky_Way_as_massive_as_3_trillion_suns. Retrieved 2009-01-14. 

Del Peloso, E. F. (2005). “The age of the Galactic thin disk from Th/Eu nucleocosmochronology”. Astronomy and Astrophysics 440: 1153. doi:10.1051/0004-6361:20053307. ariv:astro-ph/0506458. Bibcode: 2005A&A…440.1153D. 

Ortwin, Gerhard (2002). “Mass distribution in our galaxy”. Space Science Reviews 100 (1/4): 129138. doi:10.1023/A:1015818111633. http://adsabs.harvard.edu/abs/2002astro.ph..3110G. Retrieved 2007-03-14. 

Chen, W.; Gehrels, N.; Diehl, R.; Hartmann, D. (1996). “On the spiral arm interpretation of COMPTEL 26Al map features”. Space Science Reviews 120: 315316. http://adsabs.harvard.edu/abs/1996A&AS..120C.315C. Retrieved 2007-03-14. 

McKee, Maggie (August 16, 2005). “Bar at Milky Way’s heart revealed”. New Scientist. http://www.newscientist.com/article/dn7854–bar-at-milky-ways-heart-revealed.html. Retrieved 2009-06-17. 

Karachentsev, I. D.; Kashibadze, O. G. (2006). “Masses of the local group and of the M81 group estimated from distortions in the local velocity field”. Astrophysics 49 (1): 318. doi:10.1007/s10511-006-0002-6. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006Ap…..49….3K. 

Vayntrub, Alina (2000). “Mass of the Milky Way”. The Physics Factbook. http://hypertextbook.com/facts/2000/AlinaVayntrub.shtml. Retrieved 2007-05-09. 

a b Battaglia, G.; Helmi, A.; Morrison, H.; Harding, P.; Olszewski, E. W.; Mateo, M.; Freeman, K. C.; Norris, J.; Shectman, S. A. (2005). “The radial velocity dispersion profile of the Galactic halo: Constraining the density profile of the dark halo of the Milky Way” (abstract). Monthly Notices of the Royal Astronomical Society 364: 433442. http://arxiv.org/abs/astro-ph/0506102. Retrieved 2007-05-09. 

Grant. J.; Lin, B. (2000). “The Stars of the Milky Way”. Fairfax Public Access Corporation. http://members.fcac.org/sol/chview/chv5.htm. Retrieved 2007-05-09. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. pp. 5051. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA50&dq=Milky+Way+%22black+hole%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA51,M1. 

Blandford, R.D. (1999). “Origin and evolution of massive black holes in galactic nuclei”. Galaxy Dynamics, proceedings of a conference held at Rutgers University, 812 Aug 1998,ASP Conference Series vol. 182. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999ASPC..182…87B&db_key=AST&data_type=HTML&format=&high=455327e36328623. 

Staff (September 12, 2005). “Introduction: Galactic Ring Survey”. Boston University. http://www.bu.edu/galacticring/new_introduction.htm. Retrieved 2007-05-10. 

a b Benjamin, R. A. (2008). “The Spiral Structure of the Galaxy: Something Old, Something New…”. in Beuther, H.; Linz, H.; Henning, T. (ed.). Massive Star Formation: Observations Confront Theory. 387. Astronomical Society of the Pacific Conference Series. pp. 375. http://adsabs.harvard.edu/abs/2008ASPC..387..375B. laysource=Space.com Lay summary (2008-06-03). 

See also Bryner, Jeanna (2008-06-03). “New Images: Milky Way Loses Two Arms”. Space.com. http://www.space.com/scienceastronomy/080603-aas-spiral-arms.html. Retrieved 2008-06-04. 

Imamura, Jim (August 10, 2006). “Mass of the Milky Way Galaxy”. University of Oregon. http://zebu.uoregon.edu/imamura/123/lecture-2/mass.html. Retrieved 2007-05-10. 

Harris, William E. (February 2003). “Catalog of Parameters for Milky Way Globular Clusters: The Database” (text). SEDS. http://www.seds.org/messier/xtra/data/mwgc.dat.txt. Retrieved 2007-05-10. 

Ibata, R.; Chapman, S.; Ferguson, A. M. N.; Lewis, G.; Irwin, M.; Tanvir, N. (2005). “On the accretion origin of a vast extended stellar disk around the Andromeda Galaxy”. Astrophysical Journal 634 (1): 287313. doi:10.1086/491727. http://adsabs.harvard.edu/abs/2005ApJ…634..287I. Retrieved 2007-05-10. 

“Outer Disk Ring?”. SolStation. http://www.solstation.com/x-objects/gal-ring.htm. Retrieved 2007-05-10. 

Reid, Mark J. (1993). “The distance to the center of the galaxy”. Annual review of astronomy and astrophysics 31: 345372. doi:10.1146/annurev.aa.31.090193.002021. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ARA%26A..31..345R&amp. Retrieved 2007-05-10. 

Eisenhauer, F.; Schdel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003). “A Geometric Determination of the Distance to the Galactic Center”. The Astrophysical Journal 597: L121124. doi:10.1086/380188. http://adsabs.harvard.edu/abs/2003astro.ph..6220E. Retrieved 2007-05-10. 

Horrobin, M.; Eisenhauer, F.; Tecza, M.; Thatte, N.; Genzel, R.; Abuter, R.; Iserlohe, C.; Schreiber, J.; Schegerer, A.; Lutz, D.; Ott, T.; Schdel, R. (2004). “First results from SPIFFI. I: The Galactic Center” (PDF). Astronomische Nachrichten 325: 120123. doi:10.1002/asna.200310181. http://www.mpe.mpg.de/SPIFFI/preprints/first_result_an1.pdf. Retrieved 2007-05-10. 

Eisenhauer, F. et al. (2005). “SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month”. The Astrophysical Journal 628 (1): 246259. doi:10.1086/430667. http://adsabs.harvard.edu/abs/2005ApJ…628..246E. Retrieved 2007-08-12. 

a b Majaess, D. J.; Turner D. G., Lane D. J. (2009). “Characteristics of the Galaxy according to Cepheids”. MNRAS 398: 263 - 270. doi:10.1111/j.1365-2966.2009.15096.x. http://adsabs.harvard.edu/abs/2009arXiv0903.4206M. 

English, Jayanne (1991-07-24). “Exposing the Stuff Between the Stars”. Hubble News Desk. http://www.ras.ucalgary.ca/CGPS/press/aas00/pr/pr_14012000/pr_14012000map1.html. Retrieved 2007-05-10. 

Gillman, M. and Erenler, H. (2008). “The galactic cycle of extinction”. International Journal of Astrobiology 7. doi:10.1017/S1473550408004047. http://journals.cambridge.org/action/displayAbstract?aid=1804088. Retrieved 2008-04-11. 

Leong, Stacy (2002). “Period of the Sun’s Orbit around the Galaxy (Cosmic Year)”. The Physics Factbook. http://hypertextbook.com/facts/2002/StacyLeong.shtml. Retrieved 2007-05-10. 

Garlick, Mark Antony (2002). The Story of the Solar System. Cambridge University. p. 46. ISBN 0521803365. 

University of California, Berkeley (2006-01-09). “Milky Way galaxy is warped and vibrating like a drum”. Press release. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2007-10-18. 

Wong, Janet (April 14, 2000). “Astrophysicist maps out our own galaxy’s end”. University of Toronto. http://www.news.utoronto.ca/bin/000414b.asp. Retrieved 2007-01-11. 

Peter Schneider (2006). Extragalactic Astronomy and Cosmology. Springer. p. 4, Figure 1.4. ISBN 3540331743. http://books.google.com/books?id=uP1Hz-6sHaMC&pg=PA100&dq=rotation+Milky+way&lr=&as_brr=0&as_pt=ALLTYPES#PPA5,M1. 

Theo Koupelis, Karl F Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. p. 492; Figure 16-13. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 21; Figure 1.13. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA20&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA21,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 298. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA4&dq=movement+%22Milky+Way%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA298,M1. 

Peirani, S (2006). “Mass determination of groups of galaxies: Effects of the cosmological constant”. New Astronomy 11: 325. doi:10.1016/j.newast.2005.08.008. 

Theo Koupelis, Karl F. Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. pp. 492, Figure 1613. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22+date:2004-2010&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

a b A M T Jackson, R.E. Enthoven (1989), Folk Lore Notes, Asian Educational Services, ISBN 8120604857, http://books.google.com/books?id=eRkuXFD93zsC, “… According to the Puranas, the milky way or akashganga is the celestial River Ganga which was brought down by Bhagirath …” 

Hormusjee Shapoorjee Spencer (1965), The Aryan ecliptic cycle: glimpses into ancient Indo-Iranian religious history from 25628 B.C. to 292 A.D., H.P. Vaswani, http://books.google.com/books?id=jdMoAAAAYAAJ, “… There are two “Gangas” one terrestrial and the other “akashic” or celestial … bear reference only to the “Akash Ganga” which is the Milky Way …” 

Edward C. Sachau (2001), Alberuni’s India: an account of the religion, philosophy, literature, geography, chronology, astronomy, customs, laws and astrology of India about A.D. 1030, Routledge, http://books.google.com/books?id=a91-t4uw8A4C, “… revolves around Kshira, i.e. the Milky Way …” 

Harutyunyan, Hayk (2003-08-29). “The Armenian name of the Milky Way” (dead link Scholar search). ArAS News (Armenian Astronomical Society (ArAS)) 6. http://www.aras.am/ARASNEWS/arasnews06.html. Retrieved 2007-01-05. 

a b Josep Puig Montada (September 28, 2007). “Ibn Bajja”. Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/ibn-bajja. Retrieved 2008-07-11. 

Mohamed, Mohaini (2000), Great Muslim Mathematicians, Penerbit UTM, pp. 4950, ISBN 9835201579 

Hamid-Eddine Bouali, Mourad Zghal, Zohra Ben Lakhdar (2005). “Popularisation of Optical Phenomena: Establishing the First Ibn Al-Haytham Workshop on Photography” (PDF). The Education and Training in Optics and Photonics Conference. http://spie.org/etop/ETOP2005_080.pdf. Retrieved 2008-07-08. 

O’Connor, John J.; Robertson, Edmund F., “Abu Rayhan Muhammad ibn Ahmad al-Biruni”, MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Biruni.html .

Livingston, John W. (1971), “Ibn Qayyim al-Jawziyyah: A Fourteenth Century Defense against Astrological Divination and Alchemical Transmutation”, Journal of the American Oriental Society 91 (1): 96103 , doi:10.2307/600445 

O’Connor, J. J.; Robertson, E. F. (November 2002). “Galileo Galilei”. University of St Andrews. http://www-gap.dcs.st-and.ac.uk/history/Biographies/Galileo.html. Retrieved 2007-01-08. 

Evans, J. C. (November 24 1998). “Our Galaxy”. George Mason University. http://physics.gmu.edu/jevans/astr103/CourseNotes/ECText/ch20_txt.htm. Retrieved 2007-01-04. 

Abbey, Lenny. “The Earl of Rosse and the Leviathan of Parsontown”. The Compleat Amateur Astronomer. http://labbey.com/Telescopes/Parsontown.html. Retrieved 2007-01-04. 

Heber D. Curtis (1988). “Novae in Spiral Nebulae and the Island Universe Theory”. Publications of the Astronomical Society of the Pacific 100: 6. doi:10.1086/132128. http://adsabs.harvard.edu/abs/1988PASP..100….6C. 

Weaver, Harold F.. “Robert Julius Trumpler”. National Academy of Sciences. http://www.nap.edu/readingroom/books/biomems/rtrumpler.html. Retrieved 2007-01-05. 

Hubble, E. P. (1929). “A spiral nebula as a stellar system, Messier 31″. Astrophysical Journal 69: 103158. doi:10.1086/143167. http://adsabs.harvard.edu/cgi-bin/bib_query?1929ApJ….69..103H. 

Sandage, Allan (1989). “Edwin Hubble, 18891953″. The Journal of the Royal Astronomical Society of Canada 83 (6). http://antwrp.gsfc.nasa.gov/diamond_jubilee/1996/sandage_hubble.html. Retrieved 2007-01-08. 

Further reading

Thorsten Dambeck in Sky and Telescope, “Gaia’s Mission to the Milky Way”, March 2008, p. 3639.

External links

Wikimedia Commons has media related to: Milky Way Galaxy

The Milky Way Galaxy from An Atlas of the Universe

A 3D map of the Milky Way Galaxy

Chromoscope Tools to Explore the known Milky Way

Milky Way IRAS (infrared) survey wikisky.org

Milky Way H-Alpha survey wikisky.org

Interactive full screen Silverlight map of the Milky Way

Running Rings Around the Galaxy Spitzer Space Telescope News

The Milky Way Galaxy, SEDS Messier pages

MultiWavelength Milky Way, NASA site with images and VRML models

Milky Way Explorer, detailed images in infrared with radio, microwave and hydrogen-alpha as well

Face-on Milky Way maps, within about 10 thousand parsecs

The Milky Way at the Astro-Photography Site Of Mister T. Yoshida.

Widefield Image of the Summer Milky Way

Proposed Ring around the Milky Way

Milky Way spiral gets an extra arm, New Scientist.com

Possible New Milky Way Spiral Arm, Sky and Telescope.com

The Milky Way spiral arms and a possible climate connection

Galactic center mosaic via sun-orbiting Spitzer infrared telescope

Milky Way Plan Views, The University of Calgary Radio Astronomy Laboratory

Our Growing, Breathing Galaxy, Scientific American Magazine (January 2004 Issue)

Deriving The Shape Of The Galactic Stellar Disc, SkyNightly (March 17, 2006)

Digital Sky LLC, Digital Sky’s Milky Way Panorama and other images

A new view of the Milky Way galaxy obtained by the Diffuse Infrared Background Experiment (DIRBE) on NASA’s Cosmic Background Explorer satellite (COBE).

Image of Milky Way galaxy arms, Chandra X-ray Observatory Center

The 1920 Shapley Curtis Debate on the size of the Milky Way

Milky Way Voyage India’s First & Largest Star Party

Astronomy Picture of the Day:

Composite image of the Milky Way

Milky Way Illustrated

Barred Spiral Milky Way (Illustrated)

Radioactive Clouds in the Milky Way

Milky Way Molecule Map

The Milky Way’s Gamma-Ray Halo

Moving Milkyway seen from Teneriffe without any lightpollution

Multi-Gigapixel Infrared Milky Way A zoomable, annotated version of the Spitzer Space Telescope GLIMPSE survey.

Animated tour of the Milky Way, University of Glamorgan

v  d  e

The Milky Way

Location

Universe  Virgo Supercluster  Local Group

Galactic core

Center of the Milky Way

Spiral arms

Sagittarius-Carina  Scutum-Crux  Norma-Cygnus  Perseus  Orion

Satellite galaxies

Magellanic Clouds

Large Magellanic Cloud  Small Magellanic Cloud  Magellanic Stream  Magellanic Bridge

Sagittarius Elliptical

Sagittarius Stream   Botes II  Coma Berenices  Messier 54  Palomar 12  Segue 1  Segue 2  Terzan 7

Dwarves

Botes I  Botes III  Canes Venatici I  Canes Venatici II  Canis Major  Carina  Draco  Fornax  Hercules  Leo I  Leo II  Leo IV  Leo V  Phoenix  Sculptor  Sextans Spheroidal  Ursa Major I  Ursa Major II  Ursa Minor

Other

Monoceros Ring  Virgo Stream  Willman 1

v  d  e

Earth’s location in the universe

Earth  Solar System  Local Interstellar Cloud  Local Bubble  Gould Belt  Orion Arm  Milky Way  Milky Way subgroup  Local Group  Local Supercluster  Pisces-Cetus Supercluster Complex  Large-scale structure of the cosmos  Observable universe  Universe

Each arrow should be read as “within” or “part of”.

Categories: Milky Way Galaxy Milky Way Subgroup Local Group Galactic astronomy Barred spiral galaxies Spiral galaxiesHidden categories: All articles with dead external links Articles with dead external links from April 2009 Wikipedia indefinitely move-protected pages All articles with unsourced statements Articles with unsourced statements from October 2009 Articles with unsourced statements from September 2008 Articles with unsourced statements from August 2008

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Your Source For Information On Aviation

aviation gifts

 Trying to uncover materials on Risk Management techniques finds us looking at a considerable number of results on subjects like aviation safety management systems, oil and gas, OSHA standards, financial safeguards, issues associated with environmental protection and sustenability, air traffic control, and hospital patient systems. While all these contain items of risk control, they not necessarily help your firm to uncover the risks it faces.

The majority of effective aviation safety management systems Web-based tools demand that businesses painstakingly follow the process formatted in the safety management system and practice strict dedication to the plan. The best aviation safety management systems should be flexible and customizable like SMS Pro and entertain the steps below:

Identifying Risks: Recognized risks could arise from aircraft fueling, change management, risk of obsolescence, evolving technologies, theft, or weather conditions.

Evaluating Risks: Determined risks need to be appraised in terms of possible loss of life and property created by the actual loss, as well as further loss of assets or environmental quality until the risk is managed.

Coming up With Strategies to Check the Identified Risks: Above we said that one cannot manage businesses without running a risk or taking a chance. Be as it may, one must contain the risk so as to limit probable injuries.

Carrying out Strategies: Strategies must be considered as worthless unless they are incorporated into business operations. Incorporating strategies into operations also helps to rank their usefulness and discover organizational shortcomings.

Continued Monitoring of Risk Controls: Risk management processes have to be regularly monitored to ensure that the risk that they are associated with is tackled effectively and thereby controlled. Steady observation ensures that the changing needs of the corporation are controlled.

Learning about Risk Management Experts

Consulting Companies: There are many consultancy companies that can help set up a aviation safety management systems Web-based tools. Choose a company that practices exclusively in aviation safety management systems Web-based tools for your industry and size of business. While this is a relatively costly option, you will be sure of a custom solution that will meet your enterprise’s precise needs.

Automated Software: There are many off-the-shelf aviation safety management systems Web-based tools on the market. You should choose one that suits the needs of your firm, such as a reputable product created by an Anchorage, Alaska Web design and development company. You could either use this package as it is or use it as a starting point for designing a system for your specific company. This choice is most suited to smaller corporations. It is less expensive and requires you to have some knowledge of risk mitigation and management.

The best time to set up a risk management system is when you are defining your business plan. At this stage, when all aspects of the corporation are being evaluated and discussed, risks also get discussed and examined. Setting up a risk management system at this step will help your enterprise to evaluate your risks from the early stages of business operations.

Check out great aviation risk management systems software here. NWDS is a group of Anchorage, Alaska Web designers & developers that create aviation safety tools for ICAO, FAA, IS-BAO SMS

Your Source For Information On Aviation

General Aviation Aircraft Provide Great Utility as Business Transportation

By Garrett36 Pierson36

 There are many, many reasons why we fly general aviation (GA) aircraft…from chasing the elusive $100 hamburger to introducing flying to kids through Young Eagles flights. But recently as I debriefed from a successful long business flight from Oregon to near San Diego, I reflected on how smooth and convenient this trip was, start to finish.

In 2007, we bought a 1964 Piper Cherokee 235 for both business and pleasure, and on this flight, we enjoyed some of both. It was a trip that would have been impossible on the commercial carriers at ANY price, and proved that flying your own GA aircraft is one great way to get around.

Let’s take a quick look at how GA beat the pants off the scheduled carriers. Day One began with an easy southbound leg from Eugene to KGOO (Nevada County/Grass Valley). Funny identifier, but a very nice field actually. We talked shop with a client and were back in the air at 3 PM for the longest leg of this multi-city journey. Just after 7 PM, we touched down on the USS Fallbrook, a little GA airport north of San Diego with major league drop offs at both ends. Fallbrook Airpark (L18) sits atop a “mesa” so it gets plenty of wild crosswinds blowing from everywhere. By the end of this day, we were visiting a niece and her family, including her newborn baby.

This was a day that could not have happened without a GA plane at my disposal. Between landing at larger regional airports, car rentals and drive times, social meetings in both NorCal and SoCal in the same day would have been impossible.

Day two was a relatively smooth trip north to Fresno Air Terminal for two days of business meetings and a Saturday wedding. By landing at Atlantic Aviation instead of going through the cattle yard where the scheduled airlines drop off their cargo, we were in our rental car and rolling before my luggage would have reached the carousel inside the terminal. A serious boost to our productivity.

We packed a lot into the two days on the ground in Fresno, business meetings, lunch with family, dinner with clients, a brief stop at a trade show, and the wedding. Did I mention that we also brought along a rather fragile wrapped baby gift in our GA plane? The gift arrived perfectly intact…an impossible feat via the airlines as it was too big for carry on, and it would have got murdered as checked baggage.

Day three was the simple return trip to Eugene. But our family had an important celebratory affair planned in Portland, Oregon at 4 PM, and our day was starting at a friend’s home in the foothills 30 nm east of FAT. By flying GA, we were able to get coffee and arrive at the FBO by 8 AM which had the plane fueled and ready and were wheels up at 8:20 AM. The flight plan was spot on all the way north, and we arrived back at EUG just past noon. With the convenience of GA flight, we were able to get our car and were on our way to Portland to make our afternoon function just fine.

Yes, there is a slim chance we could have maybe caught a commercial flight from FAT through SFO to PDX, rented a car and slipped into the function at about 6 PM, two hours late for the gig. But did I mention we also brought back about 20 linear feet of custom picture frame moulding, a large and delicate Peacock feather (don’t ask) and several pounds of fresh California fruit and grapes? These items could not have survived the overhead bin of the Friendly Skies, or even made it through security, but in our GA aircraft, they made the trip fine.

This, was the kind of trip that our Cherokee 235 was built for way WAY back in 1963, and 45 years later, it is still flying splendid sorties on a near-perfect schedule, sipping 12 GPH at about 121 KTAS. Oh, did I mention that the S-Tec 50 autopilot flew every leg of this trip as accurately as a $620,000 Cessna Corvalis? Sure, some of today’s modern aircraft are faster, sleeker and have more pretty pictures on their panels. But when you get right down to it, my old school cruiser can complete the same mission in more flight time burning less gas while hauling more useful payload skyward.

And at $555,000 less buy-in and dirt-cheap insurance, that is some seriously affordable utility.

Author Dan Pimentel owns a advertising agency that specializes in aviation. He has been a professional photographer since 1980 and displays his work online. He also blogs about aviation on his blog, World of Flying.

Service Providers Look for Web-Based Full-Featured Management Systems

By chris howe

 These days’s economic challenges and regulatory necessities force service suppliers to implement Internet-primarily based, integrated safety and risk management database systems to reduce their risk to public safety and ensure compliance to international flight safety standards. Several regulatory standards have surfaced since ICAO’s November 2006 SMS mandate printed in the ICAO SMS Manual 9859.

Obedience to these standards is obligatory and several organizations have adopted ICAO’s lead by publishing their own set of best techniques and auditing tips, together with IOSA, IS-BAO, Air Charter Safety Foundation, ISAGO, EU/JAR Ops (Joint Aviation Requirements) Quality Assurance. Widespread SMS tool kits are designed consistent with the principles made public in this documentation.

Solely some effective, user-friendly Internet applications became a number of the most popular integrated Safety and Risk Management Web solutions with an enterprise level database. Straightforward-to-use Web tools allow all licensed users to effortlessly consider information and generate reports while not the need of further support resources, like highly trained analysts.

Good SMS tool kits don’t claim to be the primary SMS product to integrate a Internet-based mostly quality management system, nor claim to be the first to integrate an auditing management system to manage ever-present compliance requirements. Nor do sensible SMS tool kits claim to be the first to integrate a Internet-primarily based security management system. Smart SMS tool kits do claim to to the first in the planet to integrate safety, security, quality and compliance management systems in a very user-friendly manner that doesn’t need specialists to operate. That’s why our competitors search our on-line media to be told from our solutions.

Elegant risk management systems use the same framework and processes for quality assurance audits like flight, cabin, maintenance and ground safety occurrence reporting. Fewer coaching resources are needed with smart risk management systems’ intuitive interface and clients don’t have to hire full-time specialists to manage these systems.

Perfect risk management systems give comprehensive sets of tools integrating risk-connected activities across an entire organization. Widespread risk management systems’ user-friendly Web-based mostly program covers allconnected functions from accident/incident reporting, risk assessment, compliance, analysis and investigation through to auditing and corrective action management and monitoring.

Smart risk management systems have been in production for several years and are stable products for each small and giant organizations. Great safety and quality management systems continue to be enhanced by software specialists, world-category SMS training corporations and SMS consultants all over the world.

First-rate risk management systems exceeds the requirements of international and regional airlines as well as cargo, corporate fleet and helicopter operators. Alternative organizations like airports, air traffic control service providers, ground handlers and maintenance organizations have benefited from implementing the SMS system. Proactive operators will additionally understand benefits.

Every good safety management product maximizes the effectiveness of service providers’ limited safety and quality resources by automatically identifying the high-priority areas adapted for their operations; integrating all out there data for study in a single location; and offering effective corrective action-tracking and communication processes. The simplest risk management systems integrated Internet solution helps operators manage safety, security, quality and compliance issues well.

NWDS supports this Alaska business and we are Anchorage Web Design in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS and Alaska Fishing Lodges

aviation tools

 Appearance from Earth

The Milky Way Galaxy, as viewed from Earth’s position in a spur of one of the galaxy’s spiral arms (see Sun’s location and neighborhood), appears as a hazy band of white light in the night sky arching across the entire celestial sphere. The light originates from stars and other material that lie within the galactic plane. The plane of the Milky Way is inclined by about 60 to the ecliptic (the plane of the Earth’s orbit), with the North Galactic Pole situated at right ascension 12h 49m, declination +27.4 (B1950) near beta Comae Berenices. The South Galactic Pole is near alpha Sculptoris.

The center of the galaxy lies in the direction of Sagittarius, and it is here that Milky Way looks brightest. Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth’s equatorial plane and the plane of the ecliptic relative to the galactic plane. From Sagittarius, the Milky Way appears to pass westward through the constellations of Scorpius, Ara, Norma, Triangulum Australe, Circinus, Centaurus, Musca, Crux, Carina, Vela, Puppis, Canis Major, Monoceros, Orion & Gemini, Taurus, Auriga, Perseus, Andromeda, Cassiopeia, Cepheus & Lacerta, Cygnus, Vulpecula, Sagitta, Aquila, Ophiuchus, Scutum, and back to Sagittarius. The fact that the Milky Way divides the night sky into two roughly equal hemispheres indicates that the Solar System lies close to the galactic plane. The Milky Way has a relatively low surface brightness due to the interstellar medium that fills the galactic disk, and preventing us from seeing the bright galactic center. It is thus difficult to see from any urban or suburban location suffering from light pollution.

Panoramas

360-degree photographic panorama of the galaxy.

A panorama of the Milky Way, as seen from Death Valley, 2005.

The plane of our Milky Way Galaxy, which we see edge-on from our perspective on Earth, cuts a luminous swath across the image. Credit: ESO/S. Brunier

The Milky Way arches across this rare 360-degree panorama of the night sky above the Paranal platform, home of ESO Very Large Telescope. The image was made from 37 individual frames with a total exposure time of about 30 minutes, taken in the early morning hours. The Moon is just rising and the zodiacal light shines above it, while the Milky Way stretches across the sky opposite the observatory. Credit: ESO/H. Heyer

Size

The Galactic Plane seen by the ATLASGAL survey, divided into sections. Credit ESO.

The stellar disk of the Milky Way Galaxy is approximately 100,000 light-years (91017 km) (61017 mi) in diameter, and is considered to be, on average, about 1,000 ly (91015 km) thick. It is estimated to contain at least 200 billion stars and possibly up to 400 billion stars, the exact figure depending on the number of very low-mass stars, which is highly uncertain. This can be compared to the one trillion (1012) stars of the neighbouring Andromeda Galaxy. The stellar disc does not have a sharp edge, a radius beyond which there are no stars. Rather, the number of stars drops smoothly with distance from the centre of the Galaxy. Beyond a radius of roughly 40,000 light-years (41017 km) the number of stars drops much faster with radius , for reasons that are not understood.

Extending beyond the stellar disk is a much thicker disk of gas. Recent observations indicate that the gaseous disk of the Milky Way has a thickness of around 12,000 ly (11017 km)wice the previously accepted value. As a guide to the relative physical scale of the Milky Way, if it were reduced to 10m in diameter, the Solar System, including the hypothesized Oort cloud, would be no more than 0.1mm in width.

The Galactic Halo extends outward, but is limited in size by the orbits of two Milky Way satellites, the Large and the Small Magellanic Clouds, whose perigalacticon is at 180,000 ly (21018 km). At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds, and the objects would likely be ejected from the vicinity of the Milky Way.

Recent measurements by the Very Long Baseline Array (VLBA) have revealed that the Milky Way is much more massive than some previously thought. The mass of our home galaxy is now considered to be roughly similar to that of our largest local neighbour, the Andromeda Galaxy. By using the VLBA to measure the apparent shift or parallax of far-flung star-forming regions when the Earth is on opposite sides of the Sun, the researchers were able to measure the distance to those regions using fewer assumptions than prior efforts. The newer and more accurate estimate of the galaxy’s rotational speed (and in turn the amount of dark matter contained by the galaxy) is about 254 km/s, significantly higher than the widely accepted value of 220 km/s. This in turn implies that the Milky Way has a total mass of approximately 3 trillion solar masses, about 50% more massive than previously thought.

Age

Main articles: Galaxy formation and evolution and nucleocosmochronology

A green and red Perseid meteor streaks across the sky just below the Milky Way in August 2007.

As of 2004, the age of the oldest star in the galaxy yet discovered, HE 1523-0901, is estimated to be about 13.2 billion years, nearly as old as the Universe. This estimate was determined using the UV-Visual Echelle Spectrograph of the Very Large Telescope to measure the beryllium content of two stars in globular cluster NGC 6397.citation needed The elapsed time between the rise of the first generation of stars in the Milky Way and the first generation of stars in the cluster was deduced to be 200 million to 300 million years. By including the estimated age of the stars in the globular cluster, 13.4 0.8 billion years, the estimated age of the oldest stars in the Milky Way is 13.6 0.8 billion years. The Galactic thin disk is estimated to have been formed between 6.5 and 10.1 billion years ago.

Composition and structure

The galactic center in the direction of Sagittarius. The primary stars of Sagittarius are indicated in red.

The galaxy consists of a bar-shaped core region surrounded by a disk of gas, dust and stars forming four distinct arm structures spiralling outward in a logarithmic spiral shape (see Spiral arms). The mass distribution within the galaxy closely resembles the Sbc Hubble classification, which is a spiral galaxy with relatively loosely-wound arms. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1990s. Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 which showed the galaxy’s central bar to be larger than previously suspected.

The Milky Way’s mass is thought to be about 5.8  1011 solar masses (M) comprising 200 to 400 billion stars. Its integrated absolute visual magnitude has been estimated to be 20.9. Most of the mass of the galaxy is thought to be dark matter, forming a dark matter halo of an estimated 6003000 billion M which is spread out relatively uniformly.

Galactic Center

Main article: Galactic Center

Observed structure of the Milky Way’s spiral arms. Our Sun is in the Local Spur.

The galactic disc, which bulges outward at the galactic center, has a diameter of between 70,000 and 100,000 light-years. The distance from the Sun to the galactic center is now estimated at 26,000 1400 light-years, while older estimates could put the Sun as far as 35,000 light-years from the central bulge.

The galactic center harbors a compact object of very large mass as determined by the motion of material around the center. The intense radio source named Sagittarius A*, thought to mark the center of the Milky Way, is newly confirmed to be a supermassive black hole. For a photo see Chandra X-ray Observatory; Jan. 6, 2003. Most galaxies are believed to have a supermassive black hole at their center.

The galaxy’s bar is thought to be about 27,000 light-years long, running through its center at a 44 10 degree angle to the line between the Sun and the center of the galaxy. It is composed primarily of red stars, believed to be ancient (see red dwarf, red giant). The bar is surrounded by a ring called the “5-kpc ring” that contains a large fraction of the molecular hydrogen present in the galaxy, as well as most of the Milky Way’s star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of our own galaxy.

Spiral arms

Observed and extrapolated structure of the spiral arms.

Artist’s conception of the spiral structure of the Milky Way with two major stellar arms and a bar.

Each spiral arm describes a logarithmic spiral (as do the arms of all spiral galaxies) with a pitch of approximately 12 degrees. Until recently, there were believed to be four major spiral arms which all start near the galaxy’s center. These are named as follows, according to the image at right:

Color

Arm(s)

cyan

3-kpc and Perseus Arm

purple

Norma and Outer arm (Along with a newly discovered extension)

green

Scutum-Crux Arm

pink

Carina and Sagittarius Arm

There are at least two smaller arms or spurs, including:

orange

Orion-Cygnus arm (which contains the Sun and Solar System)

Observations presented in 2008 by Robert Benjamin of the University of Wisconsin-Whitewater suggest that the Milky Way possesses only two major stellar arms: the Perseus arm and the Scutum-Centaurus arm. The rest of the arms are minor or adjunct arms. This would mean that the Milky Way is similar in appearance to NGC 1365.

Outside of the major spiral arms is the Monoceros Ring (or Outer Ring), proposed by astronomers Brian Yanny and Heidi Jo Newberg, a ring of gas and stars torn from other galaxies billions of years ago.

As is typical for many galaxies, the distribution of mass in the Milky Way Galaxy is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike the situation within the Solar System, where two-body gravitational dynamics dominate and different orbits are expected to have significantly different velocities associated with them. This difference is one of the major pieces of evidence for the existence of dark matter. Another interesting aspect is the so-called “wind-up problem” of the spiral arms. If the inner parts of the arms rotate faster than the outer part, then the galaxy will wind up so much that the spiral structure will be thinned out. But this is not what is observed in spiral galaxies; instead, astronomers propose that the spiral pattern is a density wave emanating from the galactic center. This can be likened to a moving traffic jam on a highway the cars are all moving, but there is always a region of slow-moving cars. This model also agrees with enhanced star formation in or near spiral arms; the compressional waves increase the density of molecular hydrogen and protostars form as a result.

Halo

The galactic disk is surrounded by a spheroid halo of old stars and globular clusters, of which 90% lie within 100,000 light-years, suggesting a stellar halo diameter of 200,000 light-years. However, a few globular clusters have been found farther, such as PAL 4 and AM1 at more than 200,000 light-years away from the galactic center. While the disk contains gas and dust which obscure the view in some wavelengths, the spheroid component does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but not in the halo. Open clusters also occur primarily in the disk.

Recent discoveries have added dimension to the knowledge of the Milky Way’s structure. With the discovery that the disc of the Andromeda Galaxy (M31) extends much further than previously thought, the possibility of the disk of our own galaxy extending further is apparent, and this is supported by evidence of the newly discovered Outer Arm extension of the Cygnus Arm. With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, it was found that a ring of galactic debris from its interaction with the Milky Way encircles the galactic disk.

On January 9, 2006, Mario Juri and others of Princeton University announced that the Sloan Digital Sky Survey of the northern sky found a huge and diffuse structure (spread out across an area around 5,000 times the size of a full moon) within the Milky Way that does not seem to fit within current models. The collection of stars rises close to perpendicular to the plane of the spiral arms of the galaxy. The proposed likely interpretation is that a dwarf galaxy is merging with the Milky Way. This galaxy is tentatively named the Virgo Stellar Stream and is found in the direction of Virgo about 30,000 light-years away.

Sun’s location and neighborhood

The Sun (and therefore the Earth and the Solar System) may be found close to the inner rim of the galaxy’s Orion Arm, in the Local Fluff inside the Local Bubble, and in the Gould Belt, at a distance of 7.620.32 kpc (25,0001,000 ly) from the Galactic Center. The Sun is currently 530 parsecs from the central plane of the galactic disc. The distance between the local arm and the next arm out, the Perseus Arm, is about 6,500 light-years. The Sun, and thus the Solar System, is found in the galactic habitable zone.

There are about 208 stars brighter than absolute magnitude 8.5 within 15 parsecs of the Sun, giving a density of 0.0147 such stars per cubic parsec, or 0.000424 per cubic light-year (from List of nearest bright stars). On the other hand, there are 64 known stars (of any magnitude, not counting 4 brown dwarfs) within 5 parsecs of the Sun, giving a density of 0.122 stars per cubic parsec, or 0.00352 per cubic light-year (from List of nearest stars), illustrating the fact that most stars are less bright than absolute magnitude 8.5.

The Apex of the Sun’s Way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun’s galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun’s orbit around the Galaxy is expected to be roughly elliptical with the addition of perturbations due to the galactic spiral arms and non-uniform mass distributions. In addition, the Sun oscillates up and down relative to the galactic plane approximately 2.7 times per orbit. This is very similar to how a simple harmonic oscillator works with no drag force (damping) term. These oscillations often coincide with mass extinction periods on Earth; presumably the higher density of stars close to the galactic plane leads to more impact events.

It takes the Solar System about 225250 million years to complete one orbit of the galaxy (a galactic year), so it is thought to have completed 2025 orbits during the lifetime of the Sun and 1/1250 of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Galaxy is approximately 220 km/s. At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit).

A diagram of our location in the Local Supercluster. Click to view more detail.

Environment

Main articles: Local group and Andromeda-Milky Way collision

Broad infrared view of our Milky Way Galaxy from the Spitzer Space Telescope created from more than 800,000 frames. This is the most detailed infrared picture of our galaxy to date.

Milky way starscape taken from Paranal.

Location of the starscape in relation to the rest of the galaxy.

The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, itself being part of the Virgo Supercluster.

Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 20,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a peculiar streamer of neutral hydrogen gas connecting these two small galaxies. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way. Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest Milky Way dwarf galaxies are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies, which are dynamically bound to the Milky Way, as well as some that have already been absorbed by the Milky Way, such as Omega Centauri. Observations through the zone of avoidance are frequently detecting new distant and nearby galaxies. Some galaxies consisting mostly of gas and dust may also have evaded detection so far.

In January 2006, researchers reported that the heretofore unexplained warp in the disk of the Milky Way has now been mapped and found to be a ripple or vibration set up by the Large and Small Magellanic Clouds as they circle the Galaxy, causing vibrations at certain frequencies when they pass through its edges. Previously, these two galaxies, at around 2% of the mass of the Milky Way, were considered too small to influence the Milky Way. However, by taking into account dark matter, the movement of these two galaxies creates a wake that influences the larger Milky Way. Taking dark matter into account results in an approximately twenty-fold increase in mass for the Galaxy. This calculation is according to a computer model made by Martin Weinberg of the University of Massachusetts, Amherst. In this model, the dark matter is spreading out from the galactic disc with the known gas layer. As a result, the model predicts that the gravitational effect of the Magellanic Clouds is amplified as they pass through the Galaxy.

Current measurements suggest the Andromeda Galaxy is approaching us at 100 to 140 kilometers per second. The Milky Way may collide with it in 3 to 4 billion years, depending on the importance of unknown lateral components to the galaxies’ relative motion. If they collide, individual stars within the galaxies would not collide, but instead the two galaxies will merge to form a single elliptical galaxy over the course of about a billion years.

Velocity

Galaxy rotation curve for the Milky Way. Vertical axis is speed of rotation about the galactic center. Horizontal axis is distance from the galactic center in kpcs. The sun is marked with a yellow ball. The observed curve of speed of rotation is blue. The predicted curve based upon stellar mass and gas in the Milky Way is red. Scatter in observations roughly indicated by gray bars. The difference is due to dark matter or perhaps a modification of the law of gravity.

In the general sense, the absolute velocity of any object through space is not a meaningful question according to Einstein’s special theory of relativity, which declares that there is no “preferred” inertial frame of reference in space with which to compare the object’s motion. (Motion must always be specified with respect to another object.) This must be kept in mind when discussing the Galaxy’s motion.

Astronomers believe the Milky Way is moving at approximately 630 km per second relative to the local co-moving frame of reference that moves with the Hubble flow. If the Galaxy is moving at 600 km/s, Earth travels 51.84 million km per day, or more than 18.9 billion km per year, about 4.5 times its closest distance from Pluto. The Milky Way is thought to be moving in the direction of the Great Attractor. The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda galaxy) is part of a supercluster called the Local Supercluster, centered near the Virgo Cluster: although they are moving away from each other at 967 km/s as part of the Hubble flow, the velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.

Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at around 552 km/s with respect to the photons of the CMB, toward 10.5 right ascension, -24 declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction.citation needed

The galaxy rotates about its center according to its galaxy rotation curve as shown in the figure. The discrepancy between the observed curve (relatively flat) and the curve based upon the known mass of the stars and gas in the Milky Way (decaying curve) is attributed to dark matter.

History

Etymology and beliefs

Main articles: List of names for the Milky Way and Milky Way (mythology)

There are many creation myths around the world which explain the origin of the Milky Way and give it its name. The English phrase is a translation from Ancient Greek , Galaxias, which is derived from the word for milk (, gala). This is also the origin of the word galaxy. In Greek myth, the Milky Way was caused by milk spilt by Hera when suckling Heracles.

In Sanskrit and several other Indo-Aryan languages, the Milky Way is called Akash Ganga (, Ganges of the heavens). The milky way is held to be sacred in the Hindu scriptures known as the Puranas, and the Ganges and the milky way are considered to be terrestrial-celestial analogs of each other. However, the term Kshira (, milk) is also used as an alternative name for the milky way in Hindu texts.

In a large area from Central Asia to Africa, the name for the Milky Way is related to the word for “straw”. This may have originated in ancient Armenian mythology, ( hard goghi chanaparh, or “Trail of the Straw Thief”), and been carried abroad by Arabs. In several Uralic, Turkic languages, Fenno-Ugric languages and in the Baltic languages the Milky Way is called the “Birds’ Path” (Linnunrata in Finnish), since the route of the migratory birds appear to follow the Milky Way. (The Qi Xi legend celebrated in many Asian cultures references a seasonal bridge across the Milky Way formed by birds, usually magpies or crows.) The Chinese name “Silver River” () is used throughout East Asia, including Korea and Japan. An alternative name for the Milky Way in ancient China, especially in poems, is “Heavenly Han River”(). In Japanese, “Silver River” ( ginga) means galaxies in general and the Milky Way is called the “Silver River System” ( gingakei) or the “River of Heaven” ( Amanokawa or Amanogawa). In Swedish, it is called Vintergatan, or “Winter Avenue”, because the stars in the belt were used to predict when winter would arrive.citation needed In some of the Iberian languages, the Milky Way’s name translates as the “Road of Saint James” (e.g., in Spanish it is sometimes called “El camino de Santiago”).

Discovery

See also: Galaxybservation history

The shape of the Milky Way as deduced from star counts by William Herschel in 1785; the Solar System was assumed near center.

Photograph of the “Great Andromeda Nebula” from 1899, later identified as the Andromeda Galaxy.

As Aristotle (384-322 BC) informs us in Meteorologica (DK 59 A80), the Greek philosophers Anaxagoras (ca. 500428 BC) and Democritus (450370 BC) proposed the Milky Way might consist of distant stars. However, Aristotle himself believed the Milky Way to be caused by “the ignition of the fiery exhalation of some stars which were large, numerous and close together” and that the “ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions.” The Arabian astronomer, Alhazen (965-1037 AD), refuted this by making the first attempt at observing and measuring the Milky Way’s parallax, and he thus “determined that because the Milky Way had no parallax, it was very remote from the earth and did not belong to the atmosphere.”

The Persian astronomer, Ab Rayhn al-Brn (973-1048), proposed the Milky Way galaxy to be a collection of countless nebulous stars. Avempace (d. 1138) proposed the Milky Way to be made up of many stars but appears to be a continuous image due to the effect of refraction in the Earth’s atmosphere. Ibn Qayyim Al-Jawziyya (1292-1350) proposed the Milky Way galaxy to be “a myriad of tiny stars packed together in the sphere of the fixed stars” and that that these stars are larger than planets.

Actual proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it was composed of a huge number of faint stars. In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright, speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales. The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Kant also conjectured that some of the nebulae visible in the night sky might be separate “galaxies” themselves, similar to our own.

The first attempt to describe the shape of the Milky Way and the position of the Sun within it was carried out by William Herschel in 1785 by carefully counting the number of stars in different regions of the visible sky. He produced a diagram of the shape of the Galaxy with the Solar System close to the center.

In 1845, Lord Rosse constructed a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae. He also managed to make out individual point sources in some of these nebulae, lending credence to Kant’s earlier conjecture.

In 1917, Heber Curtis had observed the nova S Andromedae within the “Great Andromeda Nebula” (Messier object M31). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within our galaxy. As a result he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the “island universes” hypothesis, which held that the spiral nebulae were actually independent galaxies. In 1920 the Great Debate took place between Harlow Shapley and Heber Curtis, concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the universe. To support his claim that the Great Andromeda Nebula was an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift.

The matter was conclusively settled by Edwin Hubble in the early 1920s using a new telescope. He was able to resolve the outer parts of some spiral nebulae as collections of individual stars and identified some Cepheid variables, thus allowing him to estimate the distance to the nebulae: they were far too distant to be part of the Milky Way. In 1936, Hubble produced a classification system for galaxies that is used to this day, the Hubble sequence.

See also

Astronomy portal

Space portal

Galactic coordinate system

Dark matter halo

Smith’s Cloud

Oort Constants

The Great Rift, a molecular dust cloud located between the solar system and the Sagittarius Arm of the Milky Way which appears to split the Milky Way into two lanes over a third of its length

MilkyWay@Home, a distributed computing project that attempts to generate highly accurate three-dimensional dynamic models of stellar streams in the immediate vicinity of our Milky Way galaxy.

References

a b c Christian, Eric; Samar, Safi-Harb. “How large is the Milky Way?”. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980317b.html. Retrieved 2007-11-28. 

http://www.nasa.gov/worldbook/galaxy_worldbook.html

http://www.scientific-web.com/en/Astronomy/Galaxies/MilkyWay.html

http://www.universetoday.com/guide-to-space/milky-way/how-many-stars-are-in-the-milky-way/

a b Frebel, Anna (2007). “Discovery of HE 1523-0901, a Strongly r-Process-enhanced Metal-poor Star with Detected Uranium”. The Astrophysical Journal 660: L117. doi:10.1086/518122. ariv:astro-ph/0703414. 

a b Bissantz, Nicolai (2003). “Gas dynamics in the Milky Way: second pattern speed and large-scale morphology”. Monthly Notices of the Royal Astronomical Society 340: 949. doi:10.1046/j.1365-8711.2003.06358.x. ariv:astro-ph/0212516. 

a b Kogut, A.; Lineweaver, C.; Smoot, G. F.; Bennett, C. L.; Banday, A.; Boggess, N. W.; Cheng, E. S.; de Amici, G.; Fixsen, D. J.; Hinshaw, G.; Jackson, P. D.; Janssen, M.; Keegstra, P.; Loewenstein, K.; Lubin, P.; Mather, J. C.; Tenorio, L.; Weiss, R.; Wilkinson, D. T.; Wright, E. L. (1993). “Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps”. Astrophysical Journal 419: 1. doi:10.1086/173453. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ApJ…419….1K. Retrieved 2007-05-10. 

Freedman, Roger A.; Kaufmann, William J. (2007). Universe. WH Freeman & Co.. p. 605. ISBN 0-7167-8584-6. 

“Galaxies Milky Way Galaxy”. Encyclopedia Britannica. 19. Encyclopedia Britannica, Inc.. 1998. pp. p. 618. 

Pasachoff, Jay M. (1994). Astronomy: From the Earth to the Universe. Harcourt School. p. 500. ISBN 0-03-001667-3. 

Sanders, Robert (January 9, 2006). “Milky Way Galaxy is warped and vibrating like a drum”. UCBerkeley News. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2006-05-24. 

Frommert, H.; Kronberg, C. (August 25, 2005). “The Milky Way Galaxy”. SEDS. http://www.seds.org/messier/more/mw.html. Retrieved 2007-05-09. 

Young, Kelly (2006-06-06). “Andromeda galaxy hosts a trillion stars”. NewScientist. http://www.newscientist.com/article/dn9282-andromeda-galaxy-hosts-a-trillion-stars.html. Retrieved 2006-06-08. 

http://arxiv.org/abs/0909.3857

“Milky Way fatter than first thought”. The Sydney Morning Herald. Australian Associated Press. 2008-02-20. http://news.smh.com.au/milky-way-fatter-than-first-thought/20080220-1tbv.html. Retrieved 2008-04-24. 

Connors, et al. (2007). “N-body simulations of the Magellanic stream”. Monthly Notices of the Royal Astronomical Society 371: 108. doi:10.1111/j.1365-2966.2006.10659.x. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?bibcode=2006MNRAS.371..108C&db_key=AST&data_type=HTML&format=&high=45a3b56f2301128. Retrieved 2007-01-26. 

“Milky Way a Swifter Spinner, More Massive, New Measurements Show”. 2009-01-05. http://www.nrao.edu/pr/2009/mwrotate/. Retrieved 2009-01-20. 

Ron Cowen (January 5, 2009). “This just in: Milky Way as massive as 3 trillion suns”. Society for Science & the Public. http://www.sciencenews.org/view/generic/id/39709/title/This_just_in_Milky_Way_as_massive_as_3_trillion_suns. Retrieved 2009-01-14. 

Del Peloso, E. F. (2005). “The age of the Galactic thin disk from Th/Eu nucleocosmochronology”. Astronomy and Astrophysics 440: 1153. doi:10.1051/0004-6361:20053307. ariv:astro-ph/0506458. Bibcode: 2005A&A…440.1153D. 

Ortwin, Gerhard (2002). “Mass distribution in our galaxy”. Space Science Reviews 100 (1/4): 129138. doi:10.1023/A:1015818111633. http://adsabs.harvard.edu/abs/2002astro.ph..3110G. Retrieved 2007-03-14. 

Chen, W.; Gehrels, N.; Diehl, R.; Hartmann, D. (1996). “On the spiral arm interpretation of COMPTEL 26Al map features”. Space Science Reviews 120: 315316. http://adsabs.harvard.edu/abs/1996A&AS..120C.315C. Retrieved 2007-03-14. 

McKee, Maggie (August 16, 2005). “Bar at Milky Way’s heart revealed”. New Scientist. http://www.newscientist.com/article/dn7854–bar-at-milky-ways-heart-revealed.html. Retrieved 2009-06-17. 

Karachentsev, I. D.; Kashibadze, O. G. (2006). “Masses of the local group and of the M81 group estimated from distortions in the local velocity field”. Astrophysics 49 (1): 318. doi:10.1007/s10511-006-0002-6. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006Ap…..49….3K. 

Vayntrub, Alina (2000). “Mass of the Milky Way”. The Physics Factbook. http://hypertextbook.com/facts/2000/AlinaVayntrub.shtml. Retrieved 2007-05-09. 

a b Battaglia, G.; Helmi, A.; Morrison, H.; Harding, P.; Olszewski, E. W.; Mateo, M.; Freeman, K. C.; Norris, J.; Shectman, S. A. (2005). “The radial velocity dispersion profile of the Galactic halo: Constraining the density profile of the dark halo of the Milky Way” (abstract). Monthly Notices of the Royal Astronomical Society 364: 433442. http://arxiv.org/abs/astro-ph/0506102. Retrieved 2007-05-09. 

Grant. J.; Lin, B. (2000). “The Stars of the Milky Way”. Fairfax Public Access Corporation. http://members.fcac.org/sol/chview/chv5.htm. Retrieved 2007-05-09. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. pp. 5051. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA50&dq=Milky+Way+%22black+hole%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA51,M1. 

Blandford, R.D. (1999). “Origin and evolution of massive black holes in galactic nuclei”. Galaxy Dynamics, proceedings of a conference held at Rutgers University, 812 Aug 1998,ASP Conference Series vol. 182. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999ASPC..182…87B&db_key=AST&data_type=HTML&format=&high=455327e36328623. 

Staff (September 12, 2005). “Introduction: Galactic Ring Survey”. Boston University. http://www.bu.edu/galacticring/new_introduction.htm. Retrieved 2007-05-10. 

a b Benjamin, R. A. (2008). “The Spiral Structure of the Galaxy: Something Old, Something New…”. in Beuther, H.; Linz, H.; Henning, T. (ed.). Massive Star Formation: Observations Confront Theory. 387. Astronomical Society of the Pacific Conference Series. pp. 375. http://adsabs.harvard.edu/abs/2008ASPC..387..375B. laysource=Space.com Lay summary (2008-06-03). 

See also Bryner, Jeanna (2008-06-03). “New Images: Milky Way Loses Two Arms”. Space.com. http://www.space.com/scienceastronomy/080603-aas-spiral-arms.html. Retrieved 2008-06-04. 

Imamura, Jim (August 10, 2006). “Mass of the Milky Way Galaxy”. University of Oregon. http://zebu.uoregon.edu/imamura/123/lecture-2/mass.html. Retrieved 2007-05-10. 

Harris, William E. (February 2003). “Catalog of Parameters for Milky Way Globular Clusters: The Database” (text). SEDS. http://www.seds.org/messier/xtra/data/mwgc.dat.txt. Retrieved 2007-05-10. 

Ibata, R.; Chapman, S.; Ferguson, A. M. N.; Lewis, G.; Irwin, M.; Tanvir, N. (2005). “On the accretion origin of a vast extended stellar disk around the Andromeda Galaxy”. Astrophysical Journal 634 (1): 287313. doi:10.1086/491727. http://adsabs.harvard.edu/abs/2005ApJ…634..287I. Retrieved 2007-05-10. 

“Outer Disk Ring?”. SolStation. http://www.solstation.com/x-objects/gal-ring.htm. Retrieved 2007-05-10. 

Reid, Mark J. (1993). “The distance to the center of the galaxy”. Annual review of astronomy and astrophysics 31: 345372. doi:10.1146/annurev.aa.31.090193.002021. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ARA%26A..31..345R&amp. Retrieved 2007-05-10. 

Eisenhauer, F.; Schdel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003). “A Geometric Determination of the Distance to the Galactic Center”. The Astrophysical Journal 597: L121124. doi:10.1086/380188. http://adsabs.harvard.edu/abs/2003astro.ph..6220E. Retrieved 2007-05-10. 

Horrobin, M.; Eisenhauer, F.; Tecza, M.; Thatte, N.; Genzel, R.; Abuter, R.; Iserlohe, C.; Schreiber, J.; Schegerer, A.; Lutz, D.; Ott, T.; Schdel, R. (2004). “First results from SPIFFI. I: The Galactic Center” (PDF). Astronomische Nachrichten 325: 120123. doi:10.1002/asna.200310181. http://www.mpe.mpg.de/SPIFFI/preprints/first_result_an1.pdf. Retrieved 2007-05-10. 

Eisenhauer, F. et al. (2005). “SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month”. The Astrophysical Journal 628 (1): 246259. doi:10.1086/430667. http://adsabs.harvard.edu/abs/2005ApJ…628..246E. Retrieved 2007-08-12. 

a b Majaess, D. J.; Turner D. G., Lane D. J. (2009). “Characteristics of the Galaxy according to Cepheids”. MNRAS 398: 263 - 270. doi:10.1111/j.1365-2966.2009.15096.x. http://adsabs.harvard.edu/abs/2009arXiv0903.4206M. 

English, Jayanne (1991-07-24). “Exposing the Stuff Between the Stars”. Hubble News Desk. http://www.ras.ucalgary.ca/CGPS/press/aas00/pr/pr_14012000/pr_14012000map1.html. Retrieved 2007-05-10. 

Gillman, M. and Erenler, H. (2008). “The galactic cycle of extinction”. International Journal of Astrobiology 7. doi:10.1017/S1473550408004047. http://journals.cambridge.org/action/displayAbstract?aid=1804088. Retrieved 2008-04-11. 

Leong, Stacy (2002). “Period of the Sun’s Orbit around the Galaxy (Cosmic Year)”. The Physics Factbook. http://hypertextbook.com/facts/2002/StacyLeong.shtml. Retrieved 2007-05-10. 

Garlick, Mark Antony (2002). The Story of the Solar System. Cambridge University. p. 46. ISBN 0521803365. 

University of California, Berkeley (2006-01-09). “Milky Way galaxy is warped and vibrating like a drum”. Press release. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2007-10-18. 

Wong, Janet (April 14, 2000). “Astrophysicist maps out our own galaxy’s end”. University of Toronto. http://www.news.utoronto.ca/bin/000414b.asp. Retrieved 2007-01-11. 

Peter Schneider (2006). Extragalactic Astronomy and Cosmology. Springer. p. 4, Figure 1.4. ISBN 3540331743. http://books.google.com/books?id=uP1Hz-6sHaMC&pg=PA100&dq=rotation+Milky+way&lr=&as_brr=0&as_pt=ALLTYPES#PPA5,M1. 

Theo Koupelis, Karl F Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. p. 492; Figure 16-13. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 21; Figure 1.13. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA20&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA21,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 298. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA4&dq=movement+%22Milky+Way%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA298,M1. 

Peirani, S (2006). “Mass determination of groups of galaxies: Effects of the cosmological constant”. New Astronomy 11: 325. doi:10.1016/j.newast.2005.08.008. 

Theo Koupelis, Karl F. Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. pp. 492, Figure 1613. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22+date:2004-2010&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

a b A M T Jackson, R.E. Enthoven (1989), Folk Lore Notes, Asian Educational Services, ISBN 8120604857, http://books.google.com/books?id=eRkuXFD93zsC, “… According to the Puranas, the milky way or akashganga is the celestial River Ganga which was brought down by Bhagirath …” 

Hormusjee Shapoorjee Spencer (1965), The Aryan ecliptic cycle: glimpses into ancient Indo-Iranian religious history from 25628 B.C. to 292 A.D., H.P. Vaswani, http://books.google.com/books?id=jdMoAAAAYAAJ, “… There are two “Gangas” one terrestrial and the other “akashic” or celestial … bear reference only to the “Akash Ganga” which is the Milky Way …” 

Edward C. Sachau (2001), Alberuni’s India: an account of the religion, philosophy, literature, geography, chronology, astronomy, customs, laws and astrology of India about A.D. 1030, Routledge, http://books.google.com/books?id=a91-t4uw8A4C, “… revolves around Kshira, i.e. the Milky Way …” 

Harutyunyan, Hayk (2003-08-29). “The Armenian name of the Milky Way” (dead link Scholar search). ArAS News (Armenian Astronomical Society (ArAS)) 6. http://www.aras.am/ARASNEWS/arasnews06.html. Retrieved 2007-01-05. 

a b Josep Puig Montada (September 28, 2007). “Ibn Bajja”. Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/ibn-bajja. Retrieved 2008-07-11. 

Mohamed, Mohaini (2000), Great Muslim Mathematicians, Penerbit UTM, pp. 4950, ISBN 9835201579 

Hamid-Eddine Bouali, Mourad Zghal, Zohra Ben Lakhdar (2005). “Popularisation of Optical Phenomena: Establishing the First Ibn Al-Haytham Workshop on Photography” (PDF). The Education and Training in Optics and Photonics Conference. http://spie.org/etop/ETOP2005_080.pdf. Retrieved 2008-07-08. 

O’Connor, John J.; Robertson, Edmund F., “Abu Rayhan Muhammad ibn Ahmad al-Biruni”, MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Biruni.html .

Livingston, John W. (1971), “Ibn Qayyim al-Jawziyyah: A Fourteenth Century Defense against Astrological Divination and Alchemical Transmutation”, Journal of the American Oriental Society 91 (1): 96103 , doi:10.2307/600445 

O’Connor, J. J.; Robertson, E. F. (November 2002). “Galileo Galilei”. University of St Andrews. http://www-gap.dcs.st-and.ac.uk/history/Biographies/Galileo.html. Retrieved 2007-01-08. 

Evans, J. C. (November 24 1998). “Our Galaxy”. George Mason University. http://physics.gmu.edu/jevans/astr103/CourseNotes/ECText/ch20_txt.htm. Retrieved 2007-01-04. 

Abbey, Lenny. “The Earl of Rosse and the Leviathan of Parsontown”. The Compleat Amateur Astronomer. http://labbey.com/Telescopes/Parsontown.html. Retrieved 2007-01-04. 

Heber D. Curtis (1988). “Novae in Spiral Nebulae and the Island Universe Theory”. Publications of the Astronomical Society of the Pacific 100: 6. doi:10.1086/132128. http://adsabs.harvard.edu/abs/1988PASP..100….6C. 

Weaver, Harold F.. “Robert Julius Trumpler”. National Academy of Sciences. http://www.nap.edu/readingroom/books/biomems/rtrumpler.html. Retrieved 2007-01-05. 

Hubble, E. P. (1929). “A spiral nebula as a stellar system, Messier 31″. Astrophysical Journal 69: 103158. doi:10.1086/143167. http://adsabs.harvard.edu/cgi-bin/bib_query?1929ApJ….69..103H. 

Sandage, Allan (1989). “Edwin Hubble, 18891953″. The Journal of the Royal Astronomical Society of Canada 83 (6). http://antwrp.gsfc.nasa.gov/diamond_jubilee/1996/sandage_hubble.html. Retrieved 2007-01-08. 

Further reading

Thorsten Dambeck in Sky and Telescope, “Gaia’s Mission to the Milky Way”, March 2008, p. 3639.

External links

Wikimedia Commons has media related to: Milky Way Galaxy

The Milky Way Galaxy from An Atlas of the Universe

A 3D map of the Milky Way Galaxy

Chromoscope Tools to Explore the known Milky Way

Milky Way IRAS (infrared) survey wikisky.org

Milky Way H-Alpha survey wikisky.org

Interactive full screen Silverlight map of the Milky Way

Running Rings Around the Galaxy Spitzer Space Telescope News

The Milky Way Galaxy, SEDS Messier pages

MultiWavelength Milky Way, NASA site with images and VRML models

Milky Way Explorer, detailed images in infrared with radio, microwave and hydrogen-alpha as well

Face-on Milky Way maps, within about 10 thousand parsecs

The Milky Way at the Astro-Photography Site Of Mister T. Yoshida.

Widefield Image of the Summer Milky Way

Proposed Ring around the Milky Way

Milky Way spiral gets an extra arm, New Scientist.com

Possible New Milky Way Spiral Arm, Sky and Telescope.com

The Milky Way spiral arms and a possible climate connection

Galactic center mosaic via sun-orbiting Spitzer infrared telescope

Milky Way Plan Views, The University of Calgary Radio Astronomy Laboratory

Our Growing, Breathing Galaxy, Scientific American Magazine (January 2004 Issue)

Deriving The Shape Of The Galactic Stellar Disc, SkyNightly (March 17, 2006)

Digital Sky LLC, Digital Sky’s Milky Way Panorama and other images

A new view of the Milky Way galaxy obtained by the Diffuse Infrared Background Experiment (DIRBE) on NASA’s Cosmic Background Explorer satellite (COBE).

Image of Milky Way galaxy arms, Chandra X-ray Observatory Center

The 1920 Shapley Curtis Debate on the size of the Milky Way

Milky Way Voyage India’s First & Largest Star Party

Astronomy Picture of the Day:

Composite image of the Milky Way

Milky Way Illustrated

Barred Spiral Milky Way (Illustrated)

Radioactive Clouds in the Milky Way

Milky Way Molecule Map

The Milky Way’s Gamma-Ray Halo

Moving Milkyway seen from Teneriffe without any lightpollution

Multi-Gigapixel Infrared Milky Way A zoomable, annotated version of the Spitzer Space Telescope GLIMPSE survey.

Animated tour of the Milky Way, University of Glamorgan

v  d  e

The Milky Way

Location

Universe  Virgo Supercluster  Local Group

Galactic core

Center of the Milky Way

Spiral arms

Sagittarius-Carina  Scutum-Crux  Norma-Cygnus  Perseus  Orion

Satellite galaxies

Magellanic Clouds

Large Magellanic Cloud  Small Magellanic Cloud  Magellanic Stream  Magellanic Bridge

Sagittarius Elliptical

Sagittarius Stream   Botes II  Coma Berenices  Messier 54  Palomar 12  Segue 1  Segue 2  Terzan 7

Dwarves

Botes I  Botes III  Canes Venatici I  Canes Venatici II  Canis Major  Carina  Draco  Fornax  Hercules  Leo I  Leo II  Leo IV  Leo V  Phoenix  Sculptor  Sextans Spheroidal  Ursa Major I  Ursa Major II  Ursa Minor

Other

Monoceros Ring  Virgo Stream  Willman 1

v  d  e

Earth’s location in the universe

Earth  Solar System  Local Interstellar Cloud  Local Bubble  Gould Belt  Orion Arm  Milky Way  Milky Way subgroup  Local Group  Local Supercluster  Pisces-Cetus Supercluster Complex  Large-scale structure of the cosmos  Observable universe  Universe

Each arrow should be read as “within” or “part of”.

Categories: Milky Way Galaxy Milky Way Subgroup Local Group Galactic astronomy Barred spiral galaxies Spiral galaxiesHidden categories: All articles with dead external links Articles with dead external links from April 2009 Wikipedia indefinitely move-protected pages All articles with unsourced statements Articles with unsourced statements from October 2009 Articles with unsourced statements from September 2008 Articles with unsourced statements from August 2008

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The Best Quality Management Programs Require These Key Elements

By chris howe

 Without a doubt, each business service provider is unique. National business Quality Management programs ought to be designed to handle the particular wants of individual business service providers. All official Quality Management programs typically have these two universal parts:

1. Quality Management policy statement of the aims of the chance management program and therefore the responsibilities for safety, security, quality and compliance

2. Regularly scheduled audits and inspections of premises, tools, and work practices

In this text, we have a tendency to can discuss Quality Management Policy and Audits parts of a good Quality Management Program. Many

1. Safety policy

Every basic risk management program, whether it is Quality Management or Environmental Management, needs a statement of the employers aims and also the obligations of the employer, supervisors, and workers. This statement, usually called an Quality Management policy, sometimes states:

* The employers (CEO, top management) dedication to the Quality Management program

* The employers commitment to protect the safety of employees and all stakeholders

* The goals and priorities of the business service provider’s Quality Management program

* The duties and obligations of the employer, supervisors, and employees

Successful safety policies ought to be merely written and easy to understand. They are doing not would like to be longer than some paragraphs. The written Quality Management policy should be signed by the CEO or most senior manager, whatever his title could be. It should be dated and reviewed annually. All employees ought to be created conscious of the policy and its importance. For instance, it may be given to all or any new employees and posted within the workplace, or on the business service supplier’s Internet site.

2. Recurrent audits and inspections

Normal audits and inspections of the workplace are meant to:

* Determine conditions and unsafe acts with the possibility to cause injury or injury to equipment

* Verify obligatory corrective measures

* Prevent unsafe working conditions from developing

Three different kinds of audits and inspections are defined below:

Regular, planned workplace audits and inspections: Examine buildings, structures, grounds, aircraft, tools, equipment, machinery, and work methods and practices for hazards that might cause injury or injury to aircraft or the surroundings. Schedule these audits and inspections at acceptable intervals to prevent unsafe circumstances developing. Relying on the business service provider and the sort of hazards that may develop, audits and inspections could be scheduled daily, weekly, or monthly.

Equipment audits and inspections: Workers ought to be trained to inspect their machinery, tools, and equipment frequently, following the manufacturers minimum recommendations. National regulatory agencies might also have specific requirements.

Special audits and inspections: National regulatory agencies typically require special inspections or audits after certain types of events to confirm that operations do not resume until it is safe to do so.

Business service providers audits and inspections

Quality Management inspection groups usually include both worker and management representatives. Terribly typically, a third-party auditor regularly conducts these audits and inspections. Quality Management auditing groups should be familiar with the work flow process and, whenever doable, include members of the joint safety committee or the company’s safety delegate.

Inspection checklists can facilitate guarantee that audits and inspections are thorough, results are recorded, and therefore the inspection method is standardized. A checklist is notably useful in guiding those unfamiliar with the inspection process. Checklists ought to be adapted to suit the requirements of every business service provider’s unique activities.

Every unsafe or harmful conditions found during a regular inspection or audit should be reported right away to the supervisor or employer and remedied while not delay.

Document and write all important findings for future reference. Each hazard discovered should be recorded and also the corrective actions taken to eliminate or control every hazard. Guarantee to speak this info to the joint safety committee for his or her review and approval.

NWDS supports this Alaska business and we are Anchorage Web Design in Anchorage Alaska. They also specialize in aviation risk management systems, ICAO SMS, FAA SMS, IS-BAO SMS and Custom Web Design Company

Your Source For Information On Aviation

general aviation

 Today, businesses profit by better output and efficiencies by implementing up to date quality management systems. A current quality management system can be a internet-based software application that permits corporations to practice pro-active and reactive quality management. As a result of these modern quality management software options employing a web-based system, all employees can login to the system from anyplace with a stable internet link. This suggests that companies with many sites across North America or globally can track quality performance data throughout their entire company in a distinct quality management platform. The top result is a utterly clear illustration of organizational quality performance.

Quality management systems make possible for companies to gather and track quality data in a focal, business-wide data portal that facilitates the reorganization of corporate policies, work flow, and reporting practices along with regulatory compliance. The simplest quality management systems arrange collected data into real-time reports that can be set up on company dashboards, with the power to drill-down into characteristic reports and scorecards for granular reporting particulars.

Several quality management systems tackle all areas of an effective quality program together with quality objectives and targets; quality incident reporting; quality hazard and risk assessment; quality discussion management; work observations; quality plan; training administration; document management; report management; audits administration; nonconformances and corrective/preventive actions; reporting; disaster reaction.

As a company hunts for an off-the-shelf software product to function their quality management system, they must seek for a key, corporation-wide portal that is Internet based and makes use of an enterprise-grade database. The database is most important if looking for a product that is scalable and competent to handle the needs of a growing business.

This technique is best as soon as it turns into a single, business-wide system for all quality information, guidelines, objectives, and initiatives. Real-time reporting information should be ready to be rolled-up in real-time to multiple levels of management.

Furthermore, automated operations, automated monitoring, management, and notification throughout many departments or locations eliminates the chance for human miscalculation and streamlines workflow activities in some terribly full-featured quality management systems. Several sturdy and mature systems supply terribly exhaustive progress charts and graphs that create instant, real-time compliance-progress reports and other corporate dashboards.

As pointed out already, document management stays a principal aspect of any quality mangement system. This quality monitors file revisions and approvals in a very focal, company-wide database, with the records either on the file system or in the database itself. Recent file versions and therefore the linked editing details are routinely archived for review vigilance.

Each quality management system should enable for episode treatment by every affiliate of the business. Harmonized reporting forms with data-entry guides assists to confirm staff convey quality incidents accurately and constantly business-wide. These reports ensure responsibility by escalating electronic mail notifications that forward automated escalating email notifications to specific workers, departments, or work teams accountable for certain assignments.

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Overview of Contemporary Quality Management Systems

By chris howe

 Contemporary quality management systems can be defined as a coordinated, comprehensive set of processes designed to guide and control resources to optimally manage safety, security, quality and compliance issues affecting daily operations. Effective quality management systems take unrelated processes and builds them into one coherent structure to achieve a higher level of quality performance, making quality management an integral part of overall risk management, product safety and customer satisfaction.

Today, quality management systems are are based on leadership and accountability and allow a higher degree of transparency than seen in earlier quality management models that were popular for the past several decades. Industry leaders recognize that continuous improvement require the acceptance and participation of all stakeholders. These processes requires proactive hazard identification, risk management, information control, auditing, and training and constant feedback to participating stakeholders to keep them engaged in the process. Quality mangement systems today build on what pioneers brought to the industry, and still include incident and accident investigation and analysis.

Developing a modern quality management system requires businesses to review several existing models, regulations and guidance material from around the world. Taking these steps ensures the organization will have more success to develop an effective model specifically designed for their particular industry. Many quality management systems companies offer toolkits, which are compilations of the best practices and solutions.

Advances in the art of quality management systems came from small, medium and large businesses, such as auto manufacturers, shipping companies, workers unions and groups and governments from around the world. Many consulting firms assist organizations in achieving their desired quality performance objectives while allowing them to choose the best way to reach that outcome. This is commonly known as a performance based methodology, and encourages organizations to choose solutions and tools that best suits their needs and ensures they meet their performance objectives. Quality management consultants help organizations determine their level of compliance and develop action plans to include the necessary components.

Quality management systems are needed to help the proactive identification of quality deterrents and hazards to maximize the development of a better safety culture. Furthermore, effective quality managment systems facilitate the modification of attitudes and actions of personnel in order to make a safer work place, improve product quality and achieve higher levels of customer satisfaction. Modern quality management systems help organizations to avoid wasting financial and human resources and managements time being focused on minor or irrelevant issues. The more advanced quality management systems allow managers to identify hazards, assess risk, identify quality deficiencies and build a business case to justify controls that will reduce risk to acceptable levels and improve product or service quality.

For many organizations around the world, contemporary quality management systems provide a proven process for managing risk and improving quality that ties all elements of the organization.

NWDS supports this Alaska business and we are Web Page Design Company in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS

Your Source For Information On Aviation

aviation gifts

 Without a doubt, each business service provider is unique. National business Quality Management programs ought to be designed to handle the particular wants of individual business service providers. All official Quality Management programs typically have these two universal parts:

1. Quality Management policy statement of the aims of the chance management program and therefore the responsibilities for safety, security, quality and compliance

2. Regularly scheduled audits and inspections of premises, tools, and work practices

In this text, we have a tendency to can discuss Quality Management Policy and Audits parts of a good Quality Management Program. Many

1. Safety policy

Every basic risk management program, whether it is Quality Management or Environmental Management, needs a statement of the employers aims and also the obligations of the employer, supervisors, and workers. This statement, usually called an Quality Management policy, sometimes states:

* The employers (CEO, top management) dedication to the Quality Management program

* The employers commitment to protect the safety of employees and all stakeholders

* The goals and priorities of the business service provider’s Quality Management program

* The duties and obligations of the employer, supervisors, and employees

Successful safety policies ought to be merely written and easy to understand. They are doing not would like to be longer than some paragraphs. The written Quality Management policy should be signed by the CEO or most senior manager, whatever his title could be. It should be dated and reviewed annually. All employees ought to be created conscious of the policy and its importance. For instance, it may be given to all or any new employees and posted within the workplace, or on the business service supplier’s Internet site.

2. Recurrent audits and inspections

Normal audits and inspections of the workplace are meant to:

* Determine conditions and unsafe acts with the possibility to cause injury or injury to equipment

* Verify obligatory corrective measures

* Prevent unsafe working conditions from developing

Three different kinds of audits and inspections are defined below:

Regular, planned workplace audits and inspections: Examine buildings, structures, grounds, aircraft, tools, equipment, machinery, and work methods and practices for hazards that might cause injury or injury to aircraft or the surroundings. Schedule these audits and inspections at acceptable intervals to prevent unsafe circumstances developing. Relying on the business service provider and the sort of hazards that may develop, audits and inspections could be scheduled daily, weekly, or monthly.

Equipment audits and inspections: Workers ought to be trained to inspect their machinery, tools, and equipment frequently, following the manufacturers minimum recommendations. National regulatory agencies might also have specific requirements.

Special audits and inspections: National regulatory agencies typically require special inspections or audits after certain types of events to confirm that operations do not resume until it is safe to do so.

Business service providers audits and inspections

Quality Management inspection groups usually include both worker and management representatives. Terribly typically, a third-party auditor regularly conducts these audits and inspections. Quality Management auditing groups should be familiar with the work flow process and, whenever doable, include members of the joint safety committee or the company’s safety delegate.

Inspection checklists can facilitate guarantee that audits and inspections are thorough, results are recorded, and therefore the inspection method is standardized. A checklist is notably useful in guiding those unfamiliar with the inspection process. Checklists ought to be adapted to suit the requirements of every business service provider’s unique activities.

Every unsafe or harmful conditions found during a regular inspection or audit should be reported right away to the supervisor or employer and remedied while not delay.

Document and write all important findings for future reference. Each hazard discovered should be recorded and also the corrective actions taken to eliminate or control every hazard. Guarantee to speak this info to the joint safety committee for his or her review and approval.

NWDS supports this Alaska business and we are Anchorage Web Design in Anchorage Alaska. They also specialize in aviation risk management systems, ICAO SMS, FAA SMS, IS-BAO SMS and Custom Web Design Company

Milky Way

By w3hbre

 Appearance from Earth

The Milky Way Galaxy, as viewed from Earth’s position in a spur of one of the galaxy’s spiral arms (see Sun’s location and neighborhood), appears as a hazy band of white light in the night sky arching across the entire celestial sphere. The light originates from stars and other material that lie within the galactic plane. The plane of the Milky Way is inclined by about 60 to the ecliptic (the plane of the Earth’s orbit), with the North Galactic Pole situated at right ascension 12h 49m, declination +27.4 (B1950) near beta Comae Berenices. The South Galactic Pole is near alpha Sculptoris.

The center of the galaxy lies in the direction of Sagittarius, and it is here that Milky Way looks brightest. Relative to the celestial equator, it passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth’s equatorial plane and the plane of the ecliptic relative to the galactic plane. From Sagittarius, the Milky Way appears to pass westward through the constellations of Scorpius, Ara, Norma, Triangulum Australe, Circinus, Centaurus, Musca, Crux, Carina, Vela, Puppis, Canis Major, Monoceros, Orion & Gemini, Taurus, Auriga, Perseus, Andromeda, Cassiopeia, Cepheus & Lacerta, Cygnus, Vulpecula, Sagitta, Aquila, Ophiuchus, Scutum, and back to Sagittarius. The fact that the Milky Way divides the night sky into two roughly equal hemispheres indicates that the Solar System lies close to the galactic plane. The Milky Way has a relatively low surface brightness due to the interstellar medium that fills the galactic disk, and preventing us from seeing the bright galactic center. It is thus difficult to see from any urban or suburban location suffering from light pollution.

Panoramas

360-degree photographic panorama of the galaxy.

A panorama of the Milky Way, as seen from Death Valley, 2005.

The plane of our Milky Way Galaxy, which we see edge-on from our perspective on Earth, cuts a luminous swath across the image. Credit: ESO/S. Brunier

The Milky Way arches across this rare 360-degree panorama of the night sky above the Paranal platform, home of ESO Very Large Telescope. The image was made from 37 individual frames with a total exposure time of about 30 minutes, taken in the early morning hours. The Moon is just rising and the zodiacal light shines above it, while the Milky Way stretches across the sky opposite the observatory. Credit: ESO/H. Heyer

Size

The Galactic Plane seen by the ATLASGAL survey, divided into sections. Credit ESO.

The stellar disk of the Milky Way Galaxy is approximately 100,000 light-years (91017 km) (61017 mi) in diameter, and is considered to be, on average, about 1,000 ly (91015 km) thick. It is estimated to contain at least 200 billion stars and possibly up to 400 billion stars, the exact figure depending on the number of very low-mass stars, which is highly uncertain. This can be compared to the one trillion (1012) stars of the neighbouring Andromeda Galaxy. The stellar disc does not have a sharp edge, a radius beyond which there are no stars. Rather, the number of stars drops smoothly with distance from the centre of the Galaxy. Beyond a radius of roughly 40,000 light-years (41017 km) the number of stars drops much faster with radius , for reasons that are not understood.

Extending beyond the stellar disk is a much thicker disk of gas. Recent observations indicate that the gaseous disk of the Milky Way has a thickness of around 12,000 ly (11017 km)wice the previously accepted value. As a guide to the relative physical scale of the Milky Way, if it were reduced to 10m in diameter, the Solar System, including the hypothesized Oort cloud, would be no more than 0.1mm in width.

The Galactic Halo extends outward, but is limited in size by the orbits of two Milky Way satellites, the Large and the Small Magellanic Clouds, whose perigalacticon is at 180,000 ly (21018 km). At this distance or beyond, the orbits of most halo objects would be disrupted by the Magellanic Clouds, and the objects would likely be ejected from the vicinity of the Milky Way.

Recent measurements by the Very Long Baseline Array (VLBA) have revealed that the Milky Way is much more massive than some previously thought. The mass of our home galaxy is now considered to be roughly similar to that of our largest local neighbour, the Andromeda Galaxy. By using the VLBA to measure the apparent shift or parallax of far-flung star-forming regions when the Earth is on opposite sides of the Sun, the researchers were able to measure the distance to those regions using fewer assumptions than prior efforts. The newer and more accurate estimate of the galaxy’s rotational speed (and in turn the amount of dark matter contained by the galaxy) is about 254 km/s, significantly higher than the widely accepted value of 220 km/s. This in turn implies that the Milky Way has a total mass of approximately 3 trillion solar masses, about 50% more massive than previously thought.

Age

Main articles: Galaxy formation and evolution and nucleocosmochronology

A green and red Perseid meteor streaks across the sky just below the Milky Way in August 2007.

As of 2004, the age of the oldest star in the galaxy yet discovered, HE 1523-0901, is estimated to be about 13.2 billion years, nearly as old as the Universe. This estimate was determined using the UV-Visual Echelle Spectrograph of the Very Large Telescope to measure the beryllium content of two stars in globular cluster NGC 6397.citation needed The elapsed time between the rise of the first generation of stars in the Milky Way and the first generation of stars in the cluster was deduced to be 200 million to 300 million years. By including the estimated age of the stars in the globular cluster, 13.4 0.8 billion years, the estimated age of the oldest stars in the Milky Way is 13.6 0.8 billion years. The Galactic thin disk is estimated to have been formed between 6.5 and 10.1 billion years ago.

Composition and structure

The galactic center in the direction of Sagittarius. The primary stars of Sagittarius are indicated in red.

The galaxy consists of a bar-shaped core region surrounded by a disk of gas, dust and stars forming four distinct arm structures spiralling outward in a logarithmic spiral shape (see Spiral arms). The mass distribution within the galaxy closely resembles the Sbc Hubble classification, which is a spiral galaxy with relatively loosely-wound arms. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1990s. Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 which showed the galaxy’s central bar to be larger than previously suspected.

The Milky Way’s mass is thought to be about 5.8  1011 solar masses (M) comprising 200 to 400 billion stars. Its integrated absolute visual magnitude has been estimated to be 20.9. Most of the mass of the galaxy is thought to be dark matter, forming a dark matter halo of an estimated 6003000 billion M which is spread out relatively uniformly.

Galactic Center

Main article: Galactic Center

Observed structure of the Milky Way’s spiral arms. Our Sun is in the Local Spur.

The galactic disc, which bulges outward at the galactic center, has a diameter of between 70,000 and 100,000 light-years. The distance from the Sun to the galactic center is now estimated at 26,000 1400 light-years, while older estimates could put the Sun as far as 35,000 light-years from the central bulge.

The galactic center harbors a compact object of very large mass as determined by the motion of material around the center. The intense radio source named Sagittarius A*, thought to mark the center of the Milky Way, is newly confirmed to be a supermassive black hole. For a photo see Chandra X-ray Observatory; Jan. 6, 2003. Most galaxies are believed to have a supermassive black hole at their center.

The galaxy’s bar is thought to be about 27,000 light-years long, running through its center at a 44 10 degree angle to the line between the Sun and the center of the galaxy. It is composed primarily of red stars, believed to be ancient (see red dwarf, red giant). The bar is surrounded by a ring called the “5-kpc ring” that contains a large fraction of the molecular hydrogen present in the galaxy, as well as most of the Milky Way’s star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of our own galaxy.

Spiral arms

Observed and extrapolated structure of the spiral arms.

Artist’s conception of the spiral structure of the Milky Way with two major stellar arms and a bar.

Each spiral arm describes a logarithmic spiral (as do the arms of all spiral galaxies) with a pitch of approximately 12 degrees. Until recently, there were believed to be four major spiral arms which all start near the galaxy’s center. These are named as follows, according to the image at right:

Color

Arm(s)

cyan

3-kpc and Perseus Arm

purple

Norma and Outer arm (Along with a newly discovered extension)

green

Scutum-Crux Arm

pink

Carina and Sagittarius Arm

There are at least two smaller arms or spurs, including:

orange

Orion-Cygnus arm (which contains the Sun and Solar System)

Observations presented in 2008 by Robert Benjamin of the University of Wisconsin-Whitewater suggest that the Milky Way possesses only two major stellar arms: the Perseus arm and the Scutum-Centaurus arm. The rest of the arms are minor or adjunct arms. This would mean that the Milky Way is similar in appearance to NGC 1365.

Outside of the major spiral arms is the Monoceros Ring (or Outer Ring), proposed by astronomers Brian Yanny and Heidi Jo Newberg, a ring of gas and stars torn from other galaxies billions of years ago.

As is typical for many galaxies, the distribution of mass in the Milky Way Galaxy is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s. Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike the situation within the Solar System, where two-body gravitational dynamics dominate and different orbits are expected to have significantly different velocities associated with them. This difference is one of the major pieces of evidence for the existence of dark matter. Another interesting aspect is the so-called “wind-up problem” of the spiral arms. If the inner parts of the arms rotate faster than the outer part, then the galaxy will wind up so much that the spiral structure will be thinned out. But this is not what is observed in spiral galaxies; instead, astronomers propose that the spiral pattern is a density wave emanating from the galactic center. This can be likened to a moving traffic jam on a highway the cars are all moving, but there is always a region of slow-moving cars. This model also agrees with enhanced star formation in or near spiral arms; the compressional waves increase the density of molecular hydrogen and protostars form as a result.

Halo

The galactic disk is surrounded by a spheroid halo of old stars and globular clusters, of which 90% lie within 100,000 light-years, suggesting a stellar halo diameter of 200,000 light-years. However, a few globular clusters have been found farther, such as PAL 4 and AM1 at more than 200,000 light-years away from the galactic center. While the disk contains gas and dust which obscure the view in some wavelengths, the spheroid component does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but not in the halo. Open clusters also occur primarily in the disk.

Recent discoveries have added dimension to the knowledge of the Milky Way’s structure. With the discovery that the disc of the Andromeda Galaxy (M31) extends much further than previously thought, the possibility of the disk of our own galaxy extending further is apparent, and this is supported by evidence of the newly discovered Outer Arm extension of the Cygnus Arm. With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of the dwarf and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, it was found that a ring of galactic debris from its interaction with the Milky Way encircles the galactic disk.

On January 9, 2006, Mario Juri and others of Princeton University announced that the Sloan Digital Sky Survey of the northern sky found a huge and diffuse structure (spread out across an area around 5,000 times the size of a full moon) within the Milky Way that does not seem to fit within current models. The collection of stars rises close to perpendicular to the plane of the spiral arms of the galaxy. The proposed likely interpretation is that a dwarf galaxy is merging with the Milky Way. This galaxy is tentatively named the Virgo Stellar Stream and is found in the direction of Virgo about 30,000 light-years away.

Sun’s location and neighborhood

The Sun (and therefore the Earth and the Solar System) may be found close to the inner rim of the galaxy’s Orion Arm, in the Local Fluff inside the Local Bubble, and in the Gould Belt, at a distance of 7.620.32 kpc (25,0001,000 ly) from the Galactic Center. The Sun is currently 530 parsecs from the central plane of the galactic disc. The distance between the local arm and the next arm out, the Perseus Arm, is about 6,500 light-years. The Sun, and thus the Solar System, is found in the galactic habitable zone.

There are about 208 stars brighter than absolute magnitude 8.5 within 15 parsecs of the Sun, giving a density of 0.0147 such stars per cubic parsec, or 0.000424 per cubic light-year (from List of nearest bright stars). On the other hand, there are 64 known stars (of any magnitude, not counting 4 brown dwarfs) within 5 parsecs of the Sun, giving a density of 0.122 stars per cubic parsec, or 0.00352 per cubic light-year (from List of nearest stars), illustrating the fact that most stars are less bright than absolute magnitude 8.5.

The Apex of the Sun’s Way, or the solar apex, is the direction that the Sun travels through space in the Milky Way. The general direction of the Sun’s galactic motion is towards the star Vega near the constellation of Hercules, at an angle of roughly 60 sky degrees to the direction of the Galactic Center. The Sun’s orbit around the Galaxy is expected to be roughly elliptical with the addition of perturbations due to the galactic spiral arms and non-uniform mass distributions. In addition, the Sun oscillates up and down relative to the galactic plane approximately 2.7 times per orbit. This is very similar to how a simple harmonic oscillator works with no drag force (damping) term. These oscillations often coincide with mass extinction periods on Earth; presumably the higher density of stars close to the galactic plane leads to more impact events.

It takes the Solar System about 225250 million years to complete one orbit of the galaxy (a galactic year), so it is thought to have completed 2025 orbits during the lifetime of the Sun and 1/1250 of a revolution since the origin of humans. The orbital speed of the Solar System about the center of the Galaxy is approximately 220 km/s. At this speed, it takes around 1,400 years for the Solar System to travel a distance of 1 light-year, or 8 days to travel 1 AU (astronomical unit).

A diagram of our location in the Local Supercluster. Click to view more detail.

Environment

Main articles: Local group and Andromeda-Milky Way collision

Broad infrared view of our Milky Way Galaxy from the Spitzer Space Telescope created from more than 800,000 frames. This is the most detailed infrared picture of our galaxy to date.

Milky way starscape taken from Paranal.

Location of the starscape in relation to the rest of the galaxy.

The Milky Way and the Andromeda Galaxy are a binary system of giant spiral galaxies belonging to a group of 50 closely bound galaxies known as the Local Group, itself being part of the Virgo Supercluster.

Two smaller galaxies and a number of dwarf galaxies in the Local Group orbit the Milky Way. The largest of these is the Large Magellanic Cloud with a diameter of 20,000 light-years. It has a close companion, the Small Magellanic Cloud. The Magellanic Stream is a peculiar streamer of neutral hydrogen gas connecting these two small galaxies. The stream is thought to have been dragged from the Magellanic Clouds in tidal interactions with the Milky Way. Some of the dwarf galaxies orbiting the Milky Way are Canis Major Dwarf (the closest), Sagittarius Dwarf Elliptical Galaxy, Ursa Minor Dwarf, Sculptor Dwarf, Sextans Dwarf, Fornax Dwarf, and Leo I Dwarf. The smallest Milky Way dwarf galaxies are only 500 light-years in diameter. These include Carina Dwarf, Draco Dwarf, and Leo II Dwarf. There may still be undetected dwarf galaxies, which are dynamically bound to the Milky Way, as well as some that have already been absorbed by the Milky Way, such as Omega Centauri. Observations through the zone of avoidance are frequently detecting new distant and nearby galaxies. Some galaxies consisting mostly of gas and dust may also have evaded detection so far.

In January 2006, researchers reported that the heretofore unexplained warp in the disk of the Milky Way has now been mapped and found to be a ripple or vibration set up by the Large and Small Magellanic Clouds as they circle the Galaxy, causing vibrations at certain frequencies when they pass through its edges. Previously, these two galaxies, at around 2% of the mass of the Milky Way, were considered too small to influence the Milky Way. However, by taking into account dark matter, the movement of these two galaxies creates a wake that influences the larger Milky Way. Taking dark matter into account results in an approximately twenty-fold increase in mass for the Galaxy. This calculation is according to a computer model made by Martin Weinberg of the University of Massachusetts, Amherst. In this model, the dark matter is spreading out from the galactic disc with the known gas layer. As a result, the model predicts that the gravitational effect of the Magellanic Clouds is amplified as they pass through the Galaxy.

Current measurements suggest the Andromeda Galaxy is approaching us at 100 to 140 kilometers per second. The Milky Way may collide with it in 3 to 4 billion years, depending on the importance of unknown lateral components to the galaxies’ relative motion. If they collide, individual stars within the galaxies would not collide, but instead the two galaxies will merge to form a single elliptical galaxy over the course of about a billion years.

Velocity

Galaxy rotation curve for the Milky Way. Vertical axis is speed of rotation about the galactic center. Horizontal axis is distance from the galactic center in kpcs. The sun is marked with a yellow ball. The observed curve of speed of rotation is blue. The predicted curve based upon stellar mass and gas in the Milky Way is red. Scatter in observations roughly indicated by gray bars. The difference is due to dark matter or perhaps a modification of the law of gravity.

In the general sense, the absolute velocity of any object through space is not a meaningful question according to Einstein’s special theory of relativity, which declares that there is no “preferred” inertial frame of reference in space with which to compare the object’s motion. (Motion must always be specified with respect to another object.) This must be kept in mind when discussing the Galaxy’s motion.

Astronomers believe the Milky Way is moving at approximately 630 km per second relative to the local co-moving frame of reference that moves with the Hubble flow. If the Galaxy is moving at 600 km/s, Earth travels 51.84 million km per day, or more than 18.9 billion km per year, about 4.5 times its closest distance from Pluto. The Milky Way is thought to be moving in the direction of the Great Attractor. The Local Group (a cluster of gravitationally bound galaxies containing, among others, the Milky Way and the Andromeda galaxy) is part of a supercluster called the Local Supercluster, centered near the Virgo Cluster: although they are moving away from each other at 967 km/s as part of the Hubble flow, the velocity is less than would be expected given the 16.8 million pc distance due to the gravitational attraction between the Local Group and the Virgo Cluster.

Another reference frame is provided by the cosmic microwave background (CMB). The Milky Way is moving at around 552 km/s with respect to the photons of the CMB, toward 10.5 right ascension, -24 declination (J2000 epoch, near the center of Hydra). This motion is observed by satellites such as the Cosmic Background Explorer (COBE) and the Wilkinson Microwave Anisotropy Probe (WMAP) as a dipole contribution to the CMB, as photons in equilibrium in the CMB frame get blue-shifted in the direction of the motion and red-shifted in the opposite direction.citation needed

The galaxy rotates about its center according to its galaxy rotation curve as shown in the figure. The discrepancy between the observed curve (relatively flat) and the curve based upon the known mass of the stars and gas in the Milky Way (decaying curve) is attributed to dark matter.

History

Etymology and beliefs

Main articles: List of names for the Milky Way and Milky Way (mythology)

There are many creation myths around the world which explain the origin of the Milky Way and give it its name. The English phrase is a translation from Ancient Greek , Galaxias, which is derived from the word for milk (, gala). This is also the origin of the word galaxy. In Greek myth, the Milky Way was caused by milk spilt by Hera when suckling Heracles.

In Sanskrit and several other Indo-Aryan languages, the Milky Way is called Akash Ganga (, Ganges of the heavens). The milky way is held to be sacred in the Hindu scriptures known as the Puranas, and the Ganges and the milky way are considered to be terrestrial-celestial analogs of each other. However, the term Kshira (, milk) is also used as an alternative name for the milky way in Hindu texts.

In a large area from Central Asia to Africa, the name for the Milky Way is related to the word for “straw”. This may have originated in ancient Armenian mythology, ( hard goghi chanaparh, or “Trail of the Straw Thief”), and been carried abroad by Arabs. In several Uralic, Turkic languages, Fenno-Ugric languages and in the Baltic languages the Milky Way is called the “Birds’ Path” (Linnunrata in Finnish), since the route of the migratory birds appear to follow the Milky Way. (The Qi Xi legend celebrated in many Asian cultures references a seasonal bridge across the Milky Way formed by birds, usually magpies or crows.) The Chinese name “Silver River” () is used throughout East Asia, including Korea and Japan. An alternative name for the Milky Way in ancient China, especially in poems, is “Heavenly Han River”(). In Japanese, “Silver River” ( ginga) means galaxies in general and the Milky Way is called the “Silver River System” ( gingakei) or the “River of Heaven” ( Amanokawa or Amanogawa). In Swedish, it is called Vintergatan, or “Winter Avenue”, because the stars in the belt were used to predict when winter would arrive.citation needed In some of the Iberian languages, the Milky Way’s name translates as the “Road of Saint James” (e.g., in Spanish it is sometimes called “El camino de Santiago”).

Discovery

See also: Galaxybservation history

The shape of the Milky Way as deduced from star counts by William Herschel in 1785; the Solar System was assumed near center.

Photograph of the “Great Andromeda Nebula” from 1899, later identified as the Andromeda Galaxy.

As Aristotle (384-322 BC) informs us in Meteorologica (DK 59 A80), the Greek philosophers Anaxagoras (ca. 500428 BC) and Democritus (450370 BC) proposed the Milky Way might consist of distant stars. However, Aristotle himself believed the Milky Way to be caused by “the ignition of the fiery exhalation of some stars which were large, numerous and close together” and that the “ignition takes place in the upper part of the atmosphere, in the region of the world which is continuous with the heavenly motions.” The Arabian astronomer, Alhazen (965-1037 AD), refuted this by making the first attempt at observing and measuring the Milky Way’s parallax, and he thus “determined that because the Milky Way had no parallax, it was very remote from the earth and did not belong to the atmosphere.”

The Persian astronomer, Ab Rayhn al-Brn (973-1048), proposed the Milky Way galaxy to be a collection of countless nebulous stars. Avempace (d. 1138) proposed the Milky Way to be made up of many stars but appears to be a continuous image due to the effect of refraction in the Earth’s atmosphere. Ibn Qayyim Al-Jawziyya (1292-1350) proposed the Milky Way galaxy to be “a myriad of tiny stars packed together in the sphere of the fixed stars” and that that these stars are larger than planets.

Actual proof of the Milky Way consisting of many stars came in 1610 when Galileo Galilei used a telescope to study the Milky Way and discovered that it was composed of a huge number of faint stars. In a treatise in 1755, Immanuel Kant, drawing on earlier work by Thomas Wright, speculated (correctly) that the Milky Way might be a rotating body of a huge number of stars, held together by gravitational forces akin to the Solar System but on much larger scales. The resulting disk of stars would be seen as a band on the sky from our perspective inside the disk. Kant also conjectured that some of the nebulae visible in the night sky might be separate “galaxies” themselves, similar to our own.

The first attempt to describe the shape of the Milky Way and the position of the Sun within it was carried out by William Herschel in 1785 by carefully counting the number of stars in different regions of the visible sky. He produced a diagram of the shape of the Galaxy with the Solar System close to the center.

In 1845, Lord Rosse constructed a new telescope and was able to distinguish between elliptical and spiral-shaped nebulae. He also managed to make out individual point sources in some of these nebulae, lending credence to Kant’s earlier conjecture.

In 1917, Heber Curtis had observed the nova S Andromedae within the “Great Andromeda Nebula” (Messier object M31). Searching the photographic record, he found 11 more novae. Curtis noticed that these novae were, on average, 10 magnitudes fainter than those that occurred within our galaxy. As a result he was able to come up with a distance estimate of 150,000 parsecs. He became a proponent of the “island universes” hypothesis, which held that the spiral nebulae were actually independent galaxies. In 1920 the Great Debate took place between Harlow Shapley and Heber Curtis, concerning the nature of the Milky Way, spiral nebulae, and the dimensions of the universe. To support his claim that the Great Andromeda Nebula was an external galaxy, Curtis noted the appearance of dark lanes resembling the dust clouds in the Milky Way, as well as the significant Doppler shift.

The matter was conclusively settled by Edwin Hubble in the early 1920s using a new telescope. He was able to resolve the outer parts of some spiral nebulae as collections of individual stars and identified some Cepheid variables, thus allowing him to estimate the distance to the nebulae: they were far too distant to be part of the Milky Way. In 1936, Hubble produced a classification system for galaxies that is used to this day, the Hubble sequence.

See also

Astronomy portal

Space portal

Galactic coordinate system

Dark matter halo

Smith’s Cloud

Oort Constants

The Great Rift, a molecular dust cloud located between the solar system and the Sagittarius Arm of the Milky Way which appears to split the Milky Way into two lanes over a third of its length

MilkyWay@Home, a distributed computing project that attempts to generate highly accurate three-dimensional dynamic models of stellar streams in the immediate vicinity of our Milky Way galaxy.

References

a b c Christian, Eric; Samar, Safi-Harb. “How large is the Milky Way?”. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980317b.html. Retrieved 2007-11-28. 

http://www.nasa.gov/worldbook/galaxy_worldbook.html

http://www.scientific-web.com/en/Astronomy/Galaxies/MilkyWay.html

http://www.universetoday.com/guide-to-space/milky-way/how-many-stars-are-in-the-milky-way/

a b Frebel, Anna (2007). “Discovery of HE 1523-0901, a Strongly r-Process-enhanced Metal-poor Star with Detected Uranium”. The Astrophysical Journal 660: L117. doi:10.1086/518122. ariv:astro-ph/0703414. 

a b Bissantz, Nicolai (2003). “Gas dynamics in the Milky Way: second pattern speed and large-scale morphology”. Monthly Notices of the Royal Astronomical Society 340: 949. doi:10.1046/j.1365-8711.2003.06358.x. ariv:astro-ph/0212516. 

a b Kogut, A.; Lineweaver, C.; Smoot, G. F.; Bennett, C. L.; Banday, A.; Boggess, N. W.; Cheng, E. S.; de Amici, G.; Fixsen, D. J.; Hinshaw, G.; Jackson, P. D.; Janssen, M.; Keegstra, P.; Loewenstein, K.; Lubin, P.; Mather, J. C.; Tenorio, L.; Weiss, R.; Wilkinson, D. T.; Wright, E. L. (1993). “Dipole Anisotropy in the COBE Differential Microwave Radiometers First-Year Sky Maps”. Astrophysical Journal 419: 1. doi:10.1086/173453. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ApJ…419….1K. Retrieved 2007-05-10. 

Freedman, Roger A.; Kaufmann, William J. (2007). Universe. WH Freeman & Co.. p. 605. ISBN 0-7167-8584-6. 

“Galaxies Milky Way Galaxy”. Encyclopedia Britannica. 19. Encyclopedia Britannica, Inc.. 1998. pp. p. 618. 

Pasachoff, Jay M. (1994). Astronomy: From the Earth to the Universe. Harcourt School. p. 500. ISBN 0-03-001667-3. 

Sanders, Robert (January 9, 2006). “Milky Way Galaxy is warped and vibrating like a drum”. UCBerkeley News. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2006-05-24. 

Frommert, H.; Kronberg, C. (August 25, 2005). “The Milky Way Galaxy”. SEDS. http://www.seds.org/messier/more/mw.html. Retrieved 2007-05-09. 

Young, Kelly (2006-06-06). “Andromeda galaxy hosts a trillion stars”. NewScientist. http://www.newscientist.com/article/dn9282-andromeda-galaxy-hosts-a-trillion-stars.html. Retrieved 2006-06-08. 

http://arxiv.org/abs/0909.3857

“Milky Way fatter than first thought”. The Sydney Morning Herald. Australian Associated Press. 2008-02-20. http://news.smh.com.au/milky-way-fatter-than-first-thought/20080220-1tbv.html. Retrieved 2008-04-24. 

Connors, et al. (2007). “N-body simulations of the Magellanic stream”. Monthly Notices of the Royal Astronomical Society 371: 108. doi:10.1111/j.1365-2966.2006.10659.x. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?bibcode=2006MNRAS.371..108C&db_key=AST&data_type=HTML&format=&high=45a3b56f2301128. Retrieved 2007-01-26. 

“Milky Way a Swifter Spinner, More Massive, New Measurements Show”. 2009-01-05. http://www.nrao.edu/pr/2009/mwrotate/. Retrieved 2009-01-20. 

Ron Cowen (January 5, 2009). “This just in: Milky Way as massive as 3 trillion suns”. Society for Science & the Public. http://www.sciencenews.org/view/generic/id/39709/title/This_just_in_Milky_Way_as_massive_as_3_trillion_suns. Retrieved 2009-01-14. 

Del Peloso, E. F. (2005). “The age of the Galactic thin disk from Th/Eu nucleocosmochronology”. Astronomy and Astrophysics 440: 1153. doi:10.1051/0004-6361:20053307. ariv:astro-ph/0506458. Bibcode: 2005A&A…440.1153D. 

Ortwin, Gerhard (2002). “Mass distribution in our galaxy”. Space Science Reviews 100 (1/4): 129138. doi:10.1023/A:1015818111633. http://adsabs.harvard.edu/abs/2002astro.ph..3110G. Retrieved 2007-03-14. 

Chen, W.; Gehrels, N.; Diehl, R.; Hartmann, D. (1996). “On the spiral arm interpretation of COMPTEL 26Al map features”. Space Science Reviews 120: 315316. http://adsabs.harvard.edu/abs/1996A&AS..120C.315C. Retrieved 2007-03-14. 

McKee, Maggie (August 16, 2005). “Bar at Milky Way’s heart revealed”. New Scientist. http://www.newscientist.com/article/dn7854–bar-at-milky-ways-heart-revealed.html. Retrieved 2009-06-17. 

Karachentsev, I. D.; Kashibadze, O. G. (2006). “Masses of the local group and of the M81 group estimated from distortions in the local velocity field”. Astrophysics 49 (1): 318. doi:10.1007/s10511-006-0002-6. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2006Ap…..49….3K. 

Vayntrub, Alina (2000). “Mass of the Milky Way”. The Physics Factbook. http://hypertextbook.com/facts/2000/AlinaVayntrub.shtml. Retrieved 2007-05-09. 

a b Battaglia, G.; Helmi, A.; Morrison, H.; Harding, P.; Olszewski, E. W.; Mateo, M.; Freeman, K. C.; Norris, J.; Shectman, S. A. (2005). “The radial velocity dispersion profile of the Galactic halo: Constraining the density profile of the dark halo of the Milky Way” (abstract). Monthly Notices of the Royal Astronomical Society 364: 433442. http://arxiv.org/abs/astro-ph/0506102. Retrieved 2007-05-09. 

Grant. J.; Lin, B. (2000). “The Stars of the Milky Way”. Fairfax Public Access Corporation. http://members.fcac.org/sol/chview/chv5.htm. Retrieved 2007-05-09. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. pp. 5051. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA50&dq=Milky+Way+%22black+hole%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA51,M1. 

Blandford, R.D. (1999). “Origin and evolution of massive black holes in galactic nuclei”. Galaxy Dynamics, proceedings of a conference held at Rutgers University, 812 Aug 1998,ASP Conference Series vol. 182. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1999ASPC..182…87B&db_key=AST&data_type=HTML&format=&high=455327e36328623. 

Staff (September 12, 2005). “Introduction: Galactic Ring Survey”. Boston University. http://www.bu.edu/galacticring/new_introduction.htm. Retrieved 2007-05-10. 

a b Benjamin, R. A. (2008). “The Spiral Structure of the Galaxy: Something Old, Something New…”. in Beuther, H.; Linz, H.; Henning, T. (ed.). Massive Star Formation: Observations Confront Theory. 387. Astronomical Society of the Pacific Conference Series. pp. 375. http://adsabs.harvard.edu/abs/2008ASPC..387..375B. laysource=Space.com Lay summary (2008-06-03). 

See also Bryner, Jeanna (2008-06-03). “New Images: Milky Way Loses Two Arms”. Space.com. http://www.space.com/scienceastronomy/080603-aas-spiral-arms.html. Retrieved 2008-06-04. 

Imamura, Jim (August 10, 2006). “Mass of the Milky Way Galaxy”. University of Oregon. http://zebu.uoregon.edu/imamura/123/lecture-2/mass.html. Retrieved 2007-05-10. 

Harris, William E. (February 2003). “Catalog of Parameters for Milky Way Globular Clusters: The Database” (text). SEDS. http://www.seds.org/messier/xtra/data/mwgc.dat.txt. Retrieved 2007-05-10. 

Ibata, R.; Chapman, S.; Ferguson, A. M. N.; Lewis, G.; Irwin, M.; Tanvir, N. (2005). “On the accretion origin of a vast extended stellar disk around the Andromeda Galaxy”. Astrophysical Journal 634 (1): 287313. doi:10.1086/491727. http://adsabs.harvard.edu/abs/2005ApJ…634..287I. Retrieved 2007-05-10. 

“Outer Disk Ring?”. SolStation. http://www.solstation.com/x-objects/gal-ring.htm. Retrieved 2007-05-10. 

Reid, Mark J. (1993). “The distance to the center of the galaxy”. Annual review of astronomy and astrophysics 31: 345372. doi:10.1146/annurev.aa.31.090193.002021. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993ARA%26A..31..345R&amp. Retrieved 2007-05-10. 

Eisenhauer, F.; Schdel, R.; Genzel, R.; Ott, T.; Tecza, M.; Abuter, R.; Eckart, A.; Alexander, T. (2003). “A Geometric Determination of the Distance to the Galactic Center”. The Astrophysical Journal 597: L121124. doi:10.1086/380188. http://adsabs.harvard.edu/abs/2003astro.ph..6220E. Retrieved 2007-05-10. 

Horrobin, M.; Eisenhauer, F.; Tecza, M.; Thatte, N.; Genzel, R.; Abuter, R.; Iserlohe, C.; Schreiber, J.; Schegerer, A.; Lutz, D.; Ott, T.; Schdel, R. (2004). “First results from SPIFFI. I: The Galactic Center” (PDF). Astronomische Nachrichten 325: 120123. doi:10.1002/asna.200310181. http://www.mpe.mpg.de/SPIFFI/preprints/first_result_an1.pdf. Retrieved 2007-05-10. 

Eisenhauer, F. et al. (2005). “SINFONI in the Galactic Center: Young Stars and Infrared Flares in the Central Light-Month”. The Astrophysical Journal 628 (1): 246259. doi:10.1086/430667. http://adsabs.harvard.edu/abs/2005ApJ…628..246E. Retrieved 2007-08-12. 

a b Majaess, D. J.; Turner D. G., Lane D. J. (2009). “Characteristics of the Galaxy according to Cepheids”. MNRAS 398: 263 - 270. doi:10.1111/j.1365-2966.2009.15096.x. http://adsabs.harvard.edu/abs/2009arXiv0903.4206M. 

English, Jayanne (1991-07-24). “Exposing the Stuff Between the Stars”. Hubble News Desk. http://www.ras.ucalgary.ca/CGPS/press/aas00/pr/pr_14012000/pr_14012000map1.html. Retrieved 2007-05-10. 

Gillman, M. and Erenler, H. (2008). “The galactic cycle of extinction”. International Journal of Astrobiology 7. doi:10.1017/S1473550408004047. http://journals.cambridge.org/action/displayAbstract?aid=1804088. Retrieved 2008-04-11. 

Leong, Stacy (2002). “Period of the Sun’s Orbit around the Galaxy (Cosmic Year)”. The Physics Factbook. http://hypertextbook.com/facts/2002/StacyLeong.shtml. Retrieved 2007-05-10. 

Garlick, Mark Antony (2002). The Story of the Solar System. Cambridge University. p. 46. ISBN 0521803365. 

University of California, Berkeley (2006-01-09). “Milky Way galaxy is warped and vibrating like a drum”. Press release. http://www.berkeley.edu/news/media/releases/2006/01/09_warp.shtml. Retrieved 2007-10-18. 

Wong, Janet (April 14, 2000). “Astrophysicist maps out our own galaxy’s end”. University of Toronto. http://www.news.utoronto.ca/bin/000414b.asp. Retrieved 2007-01-11. 

Peter Schneider (2006). Extragalactic Astronomy and Cosmology. Springer. p. 4, Figure 1.4. ISBN 3540331743. http://books.google.com/books?id=uP1Hz-6sHaMC&pg=PA100&dq=rotation+Milky+way&lr=&as_brr=0&as_pt=ALLTYPES#PPA5,M1. 

Theo Koupelis, Karl F Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. p. 492; Figure 16-13. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 21; Figure 1.13. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA20&dq=Milky+Way+%22rotation+curve%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA21,M1. 

Mark H. Jones, Robert J. Lambourne, David John Adams (2004). An Introduction to Galaxies and Cosmology. Cambridge University Press. p. 298. ISBN 0521546230. http://books.google.com/books?id=36K1PfetZegC&pg=PA4&dq=movement+%22Milky+Way%22&lr=&as_brr=0&as_pt=ALLTYPES#PPA298,M1. 

Peirani, S (2006). “Mass determination of groups of galaxies: Effects of the cosmological constant”. New Astronomy 11: 325. doi:10.1016/j.newast.2005.08.008. 

Theo Koupelis, Karl F. Kuhn (2007). In Quest of the Universe. Jones & Bartlett Publishers. pp. 492, Figure 1613. ISBN 0763743879. http://books.google.com/books?id=6rTttN4ZdyoC&pg=PA491&dq=Milky+Way+%22rotation+curve%22+date:2004-2010&lr=&as_brr=0&as_pt=ALLTYPES#PPA492,M1. 

a b A M T Jackson, R.E. Enthoven (1989), Folk Lore Notes, Asian Educational Services, ISBN 8120604857, http://books.google.com/books?id=eRkuXFD93zsC, “… According to the Puranas, the milky way or akashganga is the celestial River Ganga which was brought down by Bhagirath …” 

Hormusjee Shapoorjee Spencer (1965), The Aryan ecliptic cycle: glimpses into ancient Indo-Iranian religious history from 25628 B.C. to 292 A.D., H.P. Vaswani, http://books.google.com/books?id=jdMoAAAAYAAJ, “… There are two “Gangas” one terrestrial and the other “akashic” or celestial … bear reference only to the “Akash Ganga” which is the Milky Way …” 

Edward C. Sachau (2001), Alberuni’s India: an account of the religion, philosophy, literature, geography, chronology, astronomy, customs, laws and astrology of India about A.D. 1030, Routledge, http://books.google.com/books?id=a91-t4uw8A4C, “… revolves around Kshira, i.e. the Milky Way …” 

Harutyunyan, Hayk (2003-08-29). “The Armenian name of the Milky Way” (dead link Scholar search). ArAS News (Armenian Astronomical Society (ArAS)) 6. http://www.aras.am/ARASNEWS/arasnews06.html. Retrieved 2007-01-05. 

a b Josep Puig Montada (September 28, 2007). “Ibn Bajja”. Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/ibn-bajja. Retrieved 2008-07-11. 

Mohamed, Mohaini (2000), Great Muslim Mathematicians, Penerbit UTM, pp. 4950, ISBN 9835201579 

Hamid-Eddine Bouali, Mourad Zghal, Zohra Ben Lakhdar (2005). “Popularisation of Optical Phenomena: Establishing the First Ibn Al-Haytham Workshop on Photography” (PDF). The Education and Training in Optics and Photonics Conference. http://spie.org/etop/ETOP2005_080.pdf. Retrieved 2008-07-08. 

O’Connor, John J.; Robertson, Edmund F., “Abu Rayhan Muhammad ibn Ahmad al-Biruni”, MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Al-Biruni.html .

Livingston, John W. (1971), “Ibn Qayyim al-Jawziyyah: A Fourteenth Century Defense against Astrological Divination and Alchemical Transmutation”, Journal of the American Oriental Society 91 (1): 96103 , doi:10.2307/600445 

O’Connor, J. J.; Robertson, E. F. (November 2002). “Galileo Galilei”. University of St Andrews. http://www-gap.dcs.st-and.ac.uk/history/Biographies/Galileo.html. Retrieved 2007-01-08. 

Evans, J. C. (November 24 1998). “Our Galaxy”. George Mason University. http://physics.gmu.edu/jevans/astr103/CourseNotes/ECText/ch20_txt.htm. Retrieved 2007-01-04. 

Abbey, Lenny. “The Earl of Rosse and the Leviathan of Parsontown”. The Compleat Amateur Astronomer. http://labbey.com/Telescopes/Parsontown.html. Retrieved 2007-01-04. 

Heber D. Curtis (1988). “Novae in Spiral Nebulae and the Island Universe Theory”. Publications of the Astronomical Society of the Pacific 100: 6. doi:10.1086/132128. http://adsabs.harvard.edu/abs/1988PASP..100….6C. 

Weaver, Harold F.. “Robert Julius Trumpler”. National Academy of Sciences. http://www.nap.edu/readingroom/books/biomems/rtrumpler.html. Retrieved 2007-01-05. 

Hubble, E. P. (1929). “A spiral nebula as a stellar system, Messier 31″. Astrophysical Journal 69: 103158. doi:10.1086/143167. http://adsabs.harvard.edu/cgi-bin/bib_query?1929ApJ….69..103H. 

Sandage, Allan (1989). “Edwin Hubble, 18891953″. The Journal of the Royal Astronomical Society of Canada 83 (6). http://antwrp.gsfc.nasa.gov/diamond_jubilee/1996/sandage_hubble.html. Retrieved 2007-01-08. 

Further reading

Thorsten Dambeck in Sky and Telescope, “Gaia’s Mission to the Milky Way”, March 2008, p. 3639.

External links

Wikimedia Commons has media related to: Milky Way Galaxy

The Milky Way Galaxy from An Atlas of the Universe

A 3D map of the Milky Way Galaxy

Chromoscope Tools to Explore the known Milky Way

Milky Way IRAS (infrared) survey wikisky.org

Milky Way H-Alpha survey wikisky.org

Interactive full screen Silverlight map of the Milky Way

Running Rings Around the Galaxy Spitzer Space Telescope News

The Milky Way Galaxy, SEDS Messier pages

MultiWavelength Milky Way, NASA site with images and VRML models

Milky Way Explorer, detailed images in infrared with radio, microwave and hydrogen-alpha as well

Face-on Milky Way maps, within about 10 thousand parsecs

The Milky Way at the Astro-Photography Site Of Mister T. Yoshida.

Widefield Image of the Summer Milky Way

Proposed Ring around the Milky Way

Milky Way spiral gets an extra arm, New Scientist.com

Possible New Milky Way Spiral Arm, Sky and Telescope.com

The Milky Way spiral arms and a possible climate connection

Galactic center mosaic via sun-orbiting Spitzer infrared telescope

Milky Way Plan Views, The University of Calgary Radio Astronomy Laboratory

Our Growing, Breathing Galaxy, Scientific American Magazine (January 2004 Issue)

Deriving The Shape Of The Galactic Stellar Disc, SkyNightly (March 17, 2006)

Digital Sky LLC, Digital Sky’s Milky Way Panorama and other images

A new view of the Milky Way galaxy obtained by the Diffuse Infrared Background Experiment (DIRBE) on NASA’s Cosmic Background Explorer satellite (COBE).

Image of Milky Way galaxy arms, Chandra X-ray Observatory Center

The 1920 Shapley Curtis Debate on the size of the Milky Way

Milky Way Voyage India’s First & Largest Star Party

Astronomy Picture of the Day:

Composite image of the Milky Way

Milky Way Illustrated

Barred Spiral Milky Way (Illustrated)

Radioactive Clouds in the Milky Way

Milky Way Molecule Map

The Milky Way’s Gamma-Ray Halo

Moving Milkyway seen from Teneriffe without any lightpollution

Multi-Gigapixel Infrared Milky Way A zoomable, annotated version of the Spitzer Space Telescope GLIMPSE survey.

Animated tour of the Milky Way, University of Glamorgan

v  d  e

The Milky Way

Location

Universe  Virgo Supercluster  Local Group

Galactic core

Center of the Milky Way

Spiral arms

Sagittarius-Carina  Scutum-Crux  Norma-Cygnus  Perseus  Orion

Satellite galaxies

Magellanic Clouds

Large Magellanic Cloud  Small Magellanic Cloud  Magellanic Stream  Magellanic Bridge

Sagittarius Elliptical

Sagittarius Stream   Botes II  Coma Berenices  Messier 54  Palomar 12  Segue 1  Segue 2  Terzan 7

Dwarves

Botes I  Botes III  Canes Venatici I  Canes Venatici II  Canis Major  Carina  Draco  Fornax  Hercules  Leo I  Leo II  Leo IV  Leo V  Phoenix  Sculptor  Sextans Spheroidal  Ursa Major I  Ursa Major II  Ursa Minor

Other

Monoceros Ring  Virgo Stream  Willman 1

v  d  e

Earth’s location in the universe

Earth  Solar System  Local Interstellar Cloud  Local Bubble  Gould Belt  Orion Arm  Milky Way  Milky Way subgroup  Local Group  Local Supercluster  Pisces-Cetus Supercluster Complex  Large-scale structure of the cosmos  Observable universe  Universe

Each arrow should be read as “within” or “part of”.

Categories: Milky Way Galaxy Milky Way Subgroup Local Group Galactic astronomy Barred spiral galaxies Spiral galaxiesHidden categories: All articles with dead external links Articles with dead external links from April 2009 Wikipedia indefinitely move-protected pages All articles with unsourced statements Articles with unsourced statements from October 2009 Articles with unsourced statements from September 2008 Articles with unsourced statements from August 2008

I am a professional writer from China Quality Lighting, which contains a great deal of information about solar illuminations , aviation obstruction lights, welcome to visit!

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aviation history

 Nowadays, corporations profit by increased output and efficiencies by implementing modern quality management systems. A current quality management system can be a web-based software application that permits firms to follow pro-active and immediate quality management. As a result of these modern quality management software options employing a internet-based platform, all workers will be able to login to the system from anyplace with a steady internet connection. This suggests that businesses with multiple sites throughout North America or globally will follow quality performance information across their entire organization in a specific quality management system. The top result’s a fully clear illustration of executive quality performance.

Quality management systems make possible for companies to collect and trace quality information in a focal, corporation-wide information portal that takes care of the reform of company guidelines, work flow, and reporting practices also regulatory agreement. The simplest quality management systems arrange collected information into real-time reports that may be set up on company dashboards, with the flexibility to drill-down into separate reports and scorecards for granular reporting minutiae.

Many quality management systems focus on all parts of an efficient quality program including quality objectives and targets; quality incident reporting; quality hazard and threat assessment; quality discussion administration; work observations; quality procedure; training administration; document control; records management; audits administration; nonconformances and curative/protective actions; reporting; emergency response.

As a corporation searches for an off-the-shelf software product to function their quality management system, they ought to explore for a focal, organization-wide portal that is Web based and makes use of an enterprise-grade database. The database is generally important while searching for a result that is scalable and adept to cope with the needs of a developing organization.

This method is most excellent whenever it becomes a single, company-wide approach for all quality information, guidelines, objectives, and initiatives. Real-time reporting information should be in a position to be rolled-up in real-time to many levels of management.

Furthermore, automatic techniques, automated monitoring, administration, and notification throughout several departments or places eliminates the chance for human miscalculation and streamlines workflow activities in some very complete-featured quality management systems. Many sturdy and mature systems supply terribly complete progress charts that make immediate, real-time compliance-progress reports and alternative corporate dashboards.

As observed earlier, document management continues to remain a core element of any quality mangement system. This aspect monitors file revisions and approvals in an exceedingly central, corporation-wide database, with the records either on the file system or within the database itself. Old file versions and therefore the associated editing details are without human intervention archived for audit preparedness.

Each quality management system must enable for incident reporting by every member of the business. Uniform reporting forms with data-entry guides helps to confirm workers convey quality incidents precisely and consistently organization-wide. These charts and graphs guarantee responsibility by escalating email notifications that send automatic escalating email notifications to individual workers, departments, or work teams responsible for limited assignments.

NWDS supports this Alaska business and we are Web Page Design Company in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS

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Coming up With Your Business Risk Management Program

By chris howe

 Trying to uncover materials on Risk Management techniques comes up with tons results on market segments like aviation safety management systems, insurance, OSHA standards, financial safeguards, issues related to environmental protection and sustenability, air traffic control, and computer backup systems. While all these have components of risk management, they not necessarily help your company to discover all the risks in the environment.

The majority of effective aviation safety management systems Web-based tools require that businesses exhaustively follow the steps laid out in the safety management system and practice stringent obedience to the plan. The best aviation safety management systems should be flexible and customizable like SMS Pro and offer the steps below:

Uncovering Risks: Named risks could naturally be found in payroll operations, risk of obsolescence, competitive products, theft, or fires.

Ranking Risks: Determined risks need to be evaluaed in terms of potential loss of income and reputation created by the actual event, as well as other loss of funds or repuation until the risk is constrained.

Working up Strategies to Lesson the Uncovered Risks: We mentioned earlier one cannot control enterprises without running a risk or taking a chance. But inevitably, one must control the risk so as to lessen probable losses.

Enabling Strategies: Strategies are of no use unless they are implemented. Placing strategies into organizational processes furthermore helps to measure their usefulness and uncover operational weaknesses.

Continuous Monitoring of Risk Controls: Risk management processes have to be regularly checked to ensure that the risk that they represent is tackled promptly and thereby controlled. Continuous monitoring ensures that the changing needs of the company are managed properly.

Identifying Risk Management Help

Consulting Firms: There are a great amount of consultancy corporations that can help set up a aviation safety management systems Web-based tools. Choose a enterprise that practices exclusively in aviation safety management systems Web-based tools for your industry and size of firm. While this is a comparatively expensive option, you will be sure of a tailor-made solution that will meet your corporation’s precise requirements.

Web-based Software: There are numerous off-the-shelf aviation safety management systems Web-based tools available. You should choose one that suits the needs of your business, such as a popular product created by an Anchorage, Alaska Web design and development company. You could either adopt this package as it is or use it as a starting point for designing a system for your specific corporation. This option is most suited to smaller organizations. It is less expensive and requires you to have some knowledge of risk mitigation and management.

A good time to adopt a risk management system is when you are working up your business plan. At this stage, when all aspects of the business are being examined and discussed, risks also get discussed and ranked. Setting up a risk management system at this stage will help your organization to go over your risks from the very beginning.

Check out great aviation risk management systems software here. NWDS is a group of Anchorage, Alaska Web designers & developers that create aviation safety tools for ICAO, FAA, IS-BAO SMS

general aviation

 Trying to uncover materials on Risk Management techniques finds us looking at a considerable number of results on subjects like aviation safety management systems, oil and gas, OSHA standards, financial safeguards, issues associated with environmental protection and sustenability, air traffic control, and hospital patient systems. While all these contain items of risk control, they not necessarily help your firm to uncover the risks it faces.

The majority of effective aviation safety management systems Web-based tools demand that businesses painstakingly follow the process formatted in the safety management system and practice strict dedication to the plan. The best aviation safety management systems should be flexible and customizable like SMS Pro and entertain the steps below:

Identifying Risks: Recognized risks could arise from aircraft fueling, change management, risk of obsolescence, evolving technologies, theft, or weather conditions.

Evaluating Risks: Determined risks need to be appraised in terms of possible loss of life and property created by the actual loss, as well as further loss of assets or environmental quality until the risk is managed.

Coming up With Strategies to Check the Identified Risks: Above we said that one cannot manage businesses without running a risk or taking a chance. Be as it may, one must contain the risk so as to limit probable injuries.

Carrying out Strategies: Strategies must be considered as worthless unless they are incorporated into business operations. Incorporating strategies into operations also helps to rank their usefulness and discover organizational shortcomings.

Continued Monitoring of Risk Controls: Risk management processes have to be regularly monitored to ensure that the risk that they are associated with is tackled effectively and thereby controlled. Steady observation ensures that the changing needs of the corporation are controlled.

Learning about Risk Management Experts

Consulting Companies: There are many consultancy companies that can help set up a aviation safety management systems Web-based tools. Choose a company that practices exclusively in aviation safety management systems Web-based tools for your industry and size of business. While this is a relatively costly option, you will be sure of a custom solution that will meet your enterprise’s precise needs.

Automated Software: There are many off-the-shelf aviation safety management systems Web-based tools on the market. You should choose one that suits the needs of your firm, such as a reputable product created by an Anchorage, Alaska Web design and development company. You could either use this package as it is or use it as a starting point for designing a system for your specific company. This choice is most suited to smaller corporations. It is less expensive and requires you to have some knowledge of risk mitigation and management.

The best time to set up a risk management system is when you are defining your business plan. At this stage, when all aspects of the corporation are being evaluated and discussed, risks also get discussed and examined. Setting up a risk management system at this step will help your enterprise to evaluate your risks from the early stages of business operations.

Check out great aviation risk management systems software here. NWDS is a group of Anchorage, Alaska Web designers & developers that create aviation safety tools for ICAO, FAA, IS-BAO SMS

Advantage of having pilot health and medical experts

By Flyboy Flyboy

 There is no need to mention about the importance of insurance in todays world. Each and every thing in this world is now included in the insurance plans. Be it a persons eye or a 5-star hotel, the insurance coverage is available effectively. Even in the aviation industry, the airplane is highly insured because the cost involved in developing the aircraft is whopping high. The airlines companies do not want to face a large risk due to an unforeseen event. However, while seeking insurance coverage for the plane, there are certain insurance firms that give paramount importance to the pilots life. Thus, a wide range of pilot insurance schemes have also been available in the market so that the airlines companies or the pilots can take the advantage. The pilot insurance company prides itself on delivering unsurpassed insurance products at the finest values possible to the career pilot population. The firm also dedicates their time in offering pilot health and medical support services. They are experts in the field, hence they assure to insure pilot life insurance at affordable rates.

On hiring a pilot insurance specialist, you can easily get acquainted with varied deals and premium plans. It is noticed that many of the pilots in the professional aviation community are not aware of pilot disability insurance. Hence, the specialists make the pilots familiar with several products and services related to disability and losses at the best possible rates. In the industry, there is lump sum disability policy for permanent disability, enabling a disabled pilot to get a reduced monthly income. This is really helpful for them as they can easily survive in this world without much financial problems. Moreover, you will also come across air health monthly pay disability benefits at amazing rates. Lastly, the extended long-term disability plan allows the pilots, who are about 65 years of age, to get protection against the inability to work at all. This can be achieved only after the Disability Loss of License plan expires.

Due to a medical disability, many pilots have lost their license. Thus, the insurance company also provides re-certification assistance. In this scheme, pilots will get a lot of benefits so that it becomes easy for them to get pilot re-certification service even after the loss of license.

In case you want to know more about the subject, then you can take advantage of aviation medical bulletin a monthly health newsletter that covers up-to-date, helpful health and medical information drawn from many of the world’s most respected medical authorities and literature. You will get knowledge about medical assistance program along with various aeromedical services available in the industry. If you require details on accidental death and dismemberment, then the specialist or a bulletin will be at your service. The issue of pilot disability is given importance by the insurer.

So, fly an airplane and your pilot insurance coverage will travel with you.

Brady Michaels is the author of this article on Pilot disability insurance.

Find more information about Loss of license here.

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Overview of Contemporary Quality Management Systems

By chris howe

 Contemporary quality management systems can be defined as a coordinated, comprehensive set of processes designed to guide and control resources to optimally manage safety, security, quality and compliance issues affecting daily operations. Effective quality management systems take unrelated processes and builds them into one coherent structure to achieve a higher level of quality performance, making quality management an integral part of overall risk management, product safety and customer satisfaction.

Today, quality management systems are are based on leadership and accountability and allow a higher degree of transparency than seen in earlier quality management models that were popular for the past several decades. Industry leaders recognize that continuous improvement require the acceptance and participation of all stakeholders. These processes requires proactive hazard identification, risk management, information control, auditing, and training and constant feedback to participating stakeholders to keep them engaged in the process. Quality mangement systems today build on what pioneers brought to the industry, and still include incident and accident investigation and analysis.

Developing a modern quality management system requires businesses to review several existing models, regulations and guidance material from around the world. Taking these steps ensures the organization will have more success to develop an effective model specifically designed for their particular industry. Many quality management systems companies offer toolkits, which are compilations of the best practices and solutions.

Advances in the art of quality management systems came from small, medium and large businesses, such as auto manufacturers, shipping companies, workers unions and groups and governments from around the world. Many consulting firms assist organizations in achieving their desired quality performance objectives while allowing them to choose the best way to reach that outcome. This is commonly known as a performance based methodology, and encourages organizations to choose solutions and tools that best suits their needs and ensures they meet their performance objectives. Quality management consultants help organizations determine their level of compliance and develop action plans to include the necessary components.

Quality management systems are needed to help the proactive identification of quality deterrents and hazards to maximize the development of a better safety culture. Furthermore, effective quality managment systems facilitate the modification of attitudes and actions of personnel in order to make a safer work place, improve product quality and achieve higher levels of customer satisfaction. Modern quality management systems help organizations to avoid wasting financial and human resources and managements time being focused on minor or irrelevant issues. The more advanced quality management systems allow managers to identify hazards, assess risk, identify quality deficiencies and build a business case to justify controls that will reduce risk to acceptable levels and improve product or service quality.

For many organizations around the world, contemporary quality management systems provide a proven process for managing risk and improving quality that ties all elements of the organization.

NWDS supports this Alaska business and we are Web Page Design Company in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS

aviation history

 Today’s quality management systems can be defined as a coordinated, all-embracing arrangement of activities developed to focus and direct resources to optimally deal with safety, security, quality and compliance problems touching each day activities. Helpful quality management systems consider unrelated operations and builds them into one coherent assembly to achieve a higher degree of quality implementation, making quality management an central component of general risk administration, product safety and client satisfaction.

These days, quality management systems are are primarily based on leadership and liability and permit a better measure of transparency than found in prior quality management designs that were well-liked for the previous several decades. Business leaders concede that uninterrupted improvement require the acceptance and chipping in of all stakeholders. These functions needs hands-on hazard identification, risk management, info management, auditing, and training and recurrent response to participating stakeholders to keep them engaged within the method. Quality mangement systems nowadays develop on what pioneers delivered to the trade, and still include incident and accident inspection and analysis.

Developing a fashionable quality management system requires businesses to evaluate several existing products, regulations and steerage material from around the world. Following these actions ensures the business will have additional success to extend an effective model expressly designed for his or her particular business. Several quality management systems companies supply toolkits, which are compilations of the simplest methodologies and options.

Improvements within the skill of quality management systems came from small, medium and large enterprises, such as vehicle manufacturers, transport firms, workers unions and groups and governments from round the globe. Scores of consulting firms help organizations in attaining their most wanted quality performance objectives while permitting them to decide on the best means to achieve that outcome. This is frequently known as a accomplishment based methodology, and encourages companies to settle on resolutions and tools that most closely fits their wants and ensures they accomplish their performance goals. Quality management consultants facilitate businesses confirm their degree of compliance and develop battle plans to incorporate the mandatory components.

Quality management systems are needed to assist the proactive identification of quality deterrents and hazards to increase the expansion of a healthier safety culture. Additionally, valuable quality managment systems facilitate the modification of attitudes and actions of personnel so as to create a safer work place, upgrade merchandise quality and attain superior degrees of client satisfaction. Current quality management systems assist organizations to get around wasting monetary and individual resources and managements time being centered on inconsequential or irrelevant issues. The more innovative quality management systems enable managers to spot hazards, assess threats, establish quality challenges and put together a business reason to validate controls that will cut back threats to acceptable ranges and develop merchandise or service quality.

For many businesses throughout the world, current quality management systems provide a tested method for managing risk and improving quality that links all parts of the corporation.

NWDS supports this Alaska business and we are Web Page Design Company in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS

Your Source For Information On Aviation

Overview of Contemporary Quality Management Systems

By chris howe

 Contemporary quality management systems can be defined as a coordinated, comprehensive set of processes designed to guide and control resources to optimally manage safety, security, quality and compliance issues affecting daily operations. Effective quality management systems take unrelated processes and builds them into one coherent structure to achieve a higher level of quality performance, making quality management an integral part of overall risk management, product safety and customer satisfaction.

Today, quality management systems are are based on leadership and accountability and allow a higher degree of transparency than seen in earlier quality management models that were popular for the past several decades. Industry leaders recognize that continuous improvement require the acceptance and participation of all stakeholders. These processes requires proactive hazard identification, risk management, information control, auditing, and training and constant feedback to participating stakeholders to keep them engaged in the process. Quality mangement systems today build on what pioneers brought to the industry, and still include incident and accident investigation and analysis.

Developing a modern quality management system requires businesses to review several existing models, regulations and guidance material from around the world. Taking these steps ensures the organization will have more success to develop an effective model specifically designed for their particular industry. Many quality management systems companies offer toolkits, which are compilations of the best practices and solutions.

Advances in the art of quality management systems came from small, medium and large businesses, such as auto manufacturers, shipping companies, workers unions and groups and governments from around the world. Many consulting firms assist organizations in achieving their desired quality performance objectives while allowing them to choose the best way to reach that outcome. This is commonly known as a performance based methodology, and encourages organizations to choose solutions and tools that best suits their needs and ensures they meet their performance objectives. Quality management consultants help organizations determine their level of compliance and develop action plans to include the necessary components.

Quality management systems are needed to help the proactive identification of quality deterrents and hazards to maximize the development of a better safety culture. Furthermore, effective quality managment systems facilitate the modification of attitudes and actions of personnel in order to make a safer work place, improve product quality and achieve higher levels of customer satisfaction. Modern quality management systems help organizations to avoid wasting financial and human resources and managements time being focused on minor or irrelevant issues. The more advanced quality management systems allow managers to identify hazards, assess risk, identify quality deficiencies and build a business case to justify controls that will reduce risk to acceptable levels and improve product or service quality.

For many organizations around the world, contemporary quality management systems provide a proven process for managing risk and improving quality that ties all elements of the organization.

NWDS supports this Alaska business and we are Web Page Design Company in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS

Remembering Which is Effective tea for weight Loss

By chris howe

 Selecting the most effective tea for weight loss will be challenging, just as attempting to remember which tea is most appropriate for losing weight. This is why knowing simply a little bit of history could be helpful for you. The fascinating and controversial history of green tea began in China. It’s possible to seek out references to green tea in Chinese literature as way back as 5000 years ago. There’s an previous Chinese legend that says a man was out walking in the future when he accidently tasted the juices from a leaf of a tea plant. He thought it tasted great and even felt the tea had special medicinal properties.

Like all ancient history there are totally different stories to be told, depending on who you’ll ask. Another legend suggests it was truly an Emperor referred to as Cheen Wie who discovered tea when a tea blossom fell into a cup of hot water he was drinking.

From now on the history of green tea began to advance. In those days all tea was green. It had been only later that Oolong and black or red teas came into existence. Black tea is fermented and Oolong is semi-fermented. At that point tea was drunk fresh with new leaves being mixed with hot water. It was by now being noted that the tea was helpful to the nervous system and aided digestion.

Tea drinking grew in reputation and became a distraction of the wealthy and powerful. Excellent teas were only obtainable to people who could come up with the money for them and green teas were normally used as regional currency. Elaborate tea ceremonies developed involving giant sets of tea creating equipment. Tea homes sprung up and tea afficionados prided themselves on excellence of their leaves and their tea creating abilities.

In due course green tea found its way into Japan and therefore the Japanese developed their famous teas like Sencha, Matcha and Bancha. Green tea developed further by the launch of Oolong and black teas. This probably happened sometime after 1600 AD. Oolong tea then became extremely well-liked within the South China.

Oolong tea, which is partially fermented green tea, became widespread as a result of green tea itself was therefore economical in serving to the body burn fat. During famines, individuals decided they required to keep body fat. They switched to drinking oolong tea which contains less fat oxidizing elements. Oolong tea remains one in every of the foremost common teas in China today, and can be encountered with no trouble on my e-commerce Web sites, such in Anchorage, Alaska.

Green tea drinking wasn’t simply regarding the tea itself. An entire sub-culture of teapots, tea cups and tea sets developed. Tea grew to become an art type with different producers competing for manufacturing trendy and useful tea creating equipment. A number of the foremost famous tea pots come back from the city of Su Xing. Su Xing is still famous around the globe for purple clay tea pots. You may see examples of these on some Anchorage, Alaska website designs.

Finally tea was delivered to Europe and therefore the Americas. This happened within the 1600’s. Ever since, tea drinking has increased in recognition. Many airways give their flight crews tea on lengthy missions and may be present in their aviation risk management policies.

NWDS supports this Alaska business and we are Database Consultants in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS

aviation

 These days’s economic challenges and regulatory necessities force service suppliers to implement Internet-primarily based, integrated safety and risk management database systems to reduce their risk to public safety and ensure compliance to international flight safety standards. Several regulatory standards have surfaced since ICAO’s November 2006 SMS mandate printed in the ICAO SMS Manual 9859.

Obedience to these standards is obligatory and several organizations have adopted ICAO’s lead by publishing their own set of best techniques and auditing tips, together with IOSA, IS-BAO, Air Charter Safety Foundation, ISAGO, EU/JAR Ops (Joint Aviation Requirements) Quality Assurance. Widespread SMS tool kits are designed consistent with the principles made public in this documentation.

Solely some effective, user-friendly Internet applications became a number of the most popular integrated Safety and Risk Management Web solutions with an enterprise level database. Straightforward-to-use Web tools allow all licensed users to effortlessly consider information and generate reports while not the need of further support resources, like highly trained analysts.

Good SMS tool kits don’t claim to be the primary SMS product to integrate a Internet-based mostly quality management system, nor claim to be the first to integrate an auditing management system to manage ever-present compliance requirements. Nor do sensible SMS tool kits claim to be the first to integrate a Internet-primarily based security management system. Smart SMS tool kits do claim to to the first in the planet to integrate safety, security, quality and compliance management systems in a very user-friendly manner that doesn’t need specialists to operate. That’s why our competitors search our on-line media to be told from our solutions.

Elegant risk management systems use the same framework and processes for quality assurance audits like flight, cabin, maintenance and ground safety occurrence reporting. Fewer coaching resources are needed with smart risk management systems’ intuitive interface and clients don’t have to hire full-time specialists to manage these systems.

Perfect risk management systems give comprehensive sets of tools integrating risk-connected activities across an entire organization. Widespread risk management systems’ user-friendly Web-based mostly program covers allconnected functions from accident/incident reporting, risk assessment, compliance, analysis and investigation through to auditing and corrective action management and monitoring.

Smart risk management systems have been in production for several years and are stable products for each small and giant organizations. Great safety and quality management systems continue to be enhanced by software specialists, world-category SMS training corporations and SMS consultants all over the world.

First-rate risk management systems exceeds the requirements of international and regional airlines as well as cargo, corporate fleet and helicopter operators. Alternative organizations like airports, air traffic control service providers, ground handlers and maintenance organizations have benefited from implementing the SMS system. Proactive operators will additionally understand benefits.

Every good safety management product maximizes the effectiveness of service providers’ limited safety and quality resources by automatically identifying the high-priority areas adapted for their operations; integrating all out there data for study in a single location; and offering effective corrective action-tracking and communication processes. The simplest risk management systems integrated Internet solution helps operators manage safety, security, quality and compliance issues well.

NWDS supports this Alaska business and we are Anchorage Web Design in Anchorage Alaska. They also specialize in aviation safety management systems, ICAO SMS, FAA SMS, IS-BAO SMS and Alaska Fishing Lodges

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