The Andromeda Galaxy, also known as Messier 31, is the nearest spiral galaxy to our own Milky Way Galaxy. It is 2,900,000 light years away from us. Because it is so close to us, by astronomical standards, we can study this galaxy in better detail than other, more distant galaxies. On a clear, dark, winter night, Andromeda can be seen as a fuzzy patch of light by the naked eye. Astronomers have conducted intensive studies of the Andromeda Galaxy, in part to help increase understanding of our own Galaxy.
This 8.28 µm Midcourse Space Experiment (MSX) image comes from an instrument called SPIRIT-III (SPatial InfraRed Imaging Telescope) aboard the Midcourse Space Experiment. While the brightest emission comes from the galactic center of Andromeda, the most prominent feature is the ring of infrared light circling the galaxy. It is within this ring that vast numbers of new stars are being born. To the inside of this ring, one can also see traces of the inner spiral arms of the Andromeda Galaxy.
Credit: MSX