The Andromeda galaxy, also known as Messier 31 (M31), is the closest spiral galaxy to the Milky Way at a distance of about 2.5 million light-years. Astronomers use Andromeda to understand the ...
In the years following the launch of NASA's Hubble Space Telescope, astronomers have tallied over 1 trillion galaxies in the universe. But only one galaxy stands out as the most important nearby ...