1. By: Tori and Michelle

2.  The Andromeda galaxy is a spiral galaxy approximately 2.5 million light-years away.  It is also known as Messier 31, M31, or NGC 224. Also referred to as the Great Andromeda Nebula in older text.

3.  It gets its name from the area of the sky in which it appears, the Andromeda constellation.  This area was named after the mythological princess, Andromeda.

4.  Andromeda is the largest galaxy of the local group, which consists of the Andromeda Galaxy, the Milky Way Galaxy, the Triangulum Galaxy, and about 30 other smaller galaxies.  Although it’s the largest, not the most massive because recent findings suggest that the Milky Way contains more dark matter and may be the most massive.

5.  According to a team of astronomers reporting in 2010, Andromeda was formed out of the collision of two smaller galaxies between 5 and 9 billion years ago.

6.  Used infrared surface brightness fluctuations method, Cepheid variable method, and the Tip of the Red Giant Brach method.  Averaged together, the distance measurements give a combined distance of 2.54+/- 0.06 Mly.  Based upon the above distance, the diameter at the widest point is about 141+/-3 kly

7.  Mass estimates for Andromeda (including the dark matter) is approximately 1.2 million million solar masses.  Compared to 1.9 million million solar masses for the Milky Way.

8.  Andromeda is known to harbor a dense and compact star cluster at its very center.  In a large telescope it creates a visual impression of a star embedded in the more diffuse surrounding bulge.  The luminosity of the nucleus is in excess of the most luminous globular clusters.

9.  2006 estimates put the mass of the Milky Way to be ~80% of mass of Andromeda.  2009 study concluded that Andromeda and the Milky Way are about equal in mass.  The Andromeda Galaxy and the Milky Way are expected to collide 4.5 billion years.

10.  Apparent magnitude of 3.4, The Andromeda Galaxy is notable for being one of the brightest Messier objects, making it visible to the naked eye on moonless nights even when viewed from areas with moderate light pollutions.  Although it appears more than six times as wide as the full Moon when photographed through a larger telescope, only the brighter central region is visible to the naked eye or when viewed using a telescope.

11.  "Andromeda Galaxy." SolStation.com. Web. 18 Apr. 2011..  "Andromeda Galaxy." Test Page for Apache Installation. Web. 18 Apr. 2011..  "Andromeda Galaxy." Universe Today. Web. 18 Apr. 2011..  "Andromeda Galaxy." Wikipedia, the Free Encyclopedia. Web. 18 Apr. 2011..

12.  http://www.youtube.com/watch?v=0A2HkEo EkR0 http://www.youtube.com/watch?v=0A2HkEo EkR0