Andromeda galaxy(redirected from Andromeda (astronomy))
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Andromeda Galaxy, cataloged as M31 and NGC 224, the closest large galaxy to the Milky Way and the only one visible to the naked eye in the Northern Hemisphere. It is also known as the Great Nebula in Andromeda. It is 2.2 million light-years away and is part of the Local Group of several galaxies that includes the Milky Way, which it largely resembles in shape and composition, although the Milky Way is a barred spiral galaxy and Andromeda is a spiral galaxy. It has a diameter of about 165,000 light-years and contains at least 200 billion stars. Its two brightest companion galaxies are M32 and M110. The light arriving at earth from the Andromeda Galaxy is shifted toward the blue end of the spectrum, whereas the light from all other cosmic sources exhibits red shift.
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Andromeda galaxy(M31; NGC 224) The largest of the nearby galaxies, visible to the unaided eye as a faint oval patch of light in the constellation Andromeda. It is an intermediate (Sb) spiral (see Hubble classification), orientated at an angle of about 15° from the edge-on position, and has a bright elliptical-shaped nucleus. Its distance is currently estimated as 725 kiloparsecs (2.36 million light years). With a total luminosity roughly double that of our own Galaxy and an overall diameter of approximately 60 kiloparsecs, M31 is the largest of the established members of the Local Group. It has at least four elliptical satellites, including NGC 205 and NGC 221 (M32).
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
Andromeda Galaxy[‚an′dräm·ə·də ′gal·ək·sē]
The spiral galaxy of type Sb nearest to the Milky Way. Also known as Andromeda Nebula.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.