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Milky Way Reference Libraries

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Virgo Cluster
2010-09-16 15:18:29

The Virgo Cluster consists of galaxies at a distance of around 59 Mly away in the constellation Virgo. Containing between 1300 to 2000 galaxies the Virgo Cluster is the heart of the Local Supercluster. Its mass is estimated at 1.2 × 1015 M☉ out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc. Most of the brighter galaxies in the cluster were discovered by Charles...

Magellanic Clouds
2010-09-16 15:14:03

The two Magellanic Clouds (or Nubeculae Magellani), composed of the Large Megellanic Cloud and the Small Magellanic Cloud, are irregular dwarf galaxies visible in the southern hemisphere. They are members of our Local Group and orbit the Milky Way galaxy. Persian astronomer Al Sufi, in 964, was the first to have written anything about the Magellanic Clouds proving they have been known since...

The Local Group
2010-09-13 17:05:00

The Local Group, compromising more than 30 galaxies (including dwarf galaxies and the Milky Way), is a group of galaxies with a gravitational center located somewhere between the Milky Way and the Andromeda Galaxy. With a binary (dumbbell) shape and a total mass of (1.29 ± 0.14) × 1012M the Local group covers a 10 million light-year diameter. The local group is part of the Virgo...

Sculptor Group
2010-09-13 16:24:54

At a distance of 3.9 Mpc from the Milky Way, the Sculptor Group is one of nearest groups of galaxies to the Local Gropu. Sculptor is made up of a loose group of galaxies near the south galactic pole. The Sculptor Galaxy (NGC 253) and a few other galaxies form a gravitationally-bound core in the center of this group, however, since they are only weakly bound the group may also be described...

Aquila the Eagle Constellation
2004-10-19 04:45:44

Aquila (the Eagle) Constellation -- Location: Northern Hemisphere; Coordinates: Right Ascension: 20h; Declination: 05; Source: Various cultures - Greek, Arab, Persian, Indian, Japanese, Chinese, Korean The story behind the name In the ancient Middle Eastern and Mediterranean cultures, the constellation Aquila is seen as the shape of a flying bird. The pattern contains three prominent...

Spiral Galaxy
2004-10-19 04:45:42

Spiral Galaxy -- Among the galaxies, there are apparently three main categories, according to their appearance: the disk galaxies (`cosmic frisbies' according to P. Murdin, D. Allen, and D. Malin), consisting of a huge disk of stars and interstellar matter, which may form interesting patterns, the elliptical galaxies (`cosmic footballs') which are uniformly looking, ellipsoidal agglomerations...

Molecular Cloud
2004-10-19 04:45:41

Molecular Cloud -- Molecular clouds are interstellar nebulae that have a density and size sufficient to permit the formation of H2, molecular hydrogen. However, this molecule is difficult to detect, and the molecule most used to trace the H2 is CO (carbon monoxide). The ratio between CO luminosity and H2 mass is roughly constant, although there are reasons to doubt this assumption in...

Irregular Galaxy
2004-10-19 04:45:41

Irregular Galaxy -- In astronomy, a class of galaxy with little structure, which does not conform to any of the standard shapes in the Hubble classification. The two satellite galaxies of the Milky Way, the Magellanic Clouds, are both irregulars. Some galaxies previously classified as irregulars are now known to be normal galaxies distorted by tidal effects or undergoing bursts of star...

H II Region
2004-10-19 04:45:41

H II Region -- An H II region is an emission nebula associated with hot, young, blue stars, and star forming regions. H II, or singly-ionized hydrogen, is nebular gas ionized by ultraviolet light emitted by these hot, young stars of spectral type O and B. The sizes of H II regions are determined both by the amount of gas present, and by the luminosity of the O and B stars -- the more...

Globular Cluster
2004-10-19 04:45:41

Globular Cluster -- A globular cluster is a cluster of stars that is spherical in shape and extremely dense towards its core. Globular clusters are usually composed of hundreds of thousands of old stars, similar to the bulge of a spiral galaxy but confined to a volume of only a few cubic parsecs. Some globular clusters (like Omega Centauri in our Milky Way, and G1 in M31) are truly massive...

Word of the Day
omadhaun
  • A fool; a simpleton: a term of abuse common in Ireland and to a less extent in the Gaelic-speaking parts of Scotland.
This word is partly Irish in origin.