MINNEAPOLIS, MN – We know less about our nearest galactic neighbor than thought, astronomers announced today. A map of the outer suburbs of the Andromeda galaxy finds that its rotating disk of stars is three times bigger than previously measured.

The Andromeda galaxy is a spiral galaxy similar to our own Milky Way. Although there are smaller dwarf galaxies nearer to us, Andromeda is the closest large galaxy – at about 2 million light-years from Earth. A light-year is the distance light travels in a year, about 6 trillion miles (10 trillion kilometers).

[I thought according to Hipparcos M31 is 2.93 million light years away?]

http://space.com/scienceastronomy/050530_andromeda_size.html