M-31:
The Andromeda Galaxy.
Visible to the naked eye and almost twice as big as the
full moon, this is the largest, brightest galaxy you can see from Earth.
M-31 is 2.2 million light-years away - about
13,000,000,000,000 miles! When you look at M-31, the light falling on your eye
left the galaxy more than 2 million years ago.
In this photograph, you can see dark clouds of dust
swirling around the spiral arms of the galaxy. The bluish glow is from the combined
light of billions of stars in the galaxy. All the individual stars you see are
"foreground stars" that are part of our galaxy, the Milky Way. The
stars in the Andromeda Galaxy are so far away and so numerous that they appear
as a smooth, delicate haze in all but the largest telescopes.
