The Andromeda Galaxy in UV and Visible Light On the left is an ultraviolet GALEX image of the Andromeda Galaxy, M31, that was taken in 2003. On the right is a visible light image of the same galaxy taken by a ground based telescope. The Andromeda galaxy is the most massive member of the Local Group, a group of about 30 galaxies including the Milky Way and the Magellanic Clouds.

The GALEX image shows blue regions of young, hot, high mass stars tracing out the spiral arms where star formation is occurring, and the central orange-white "bulge" of old, cooler stars formed long ago. The red stars in this image are foreground stars in the Milky Way galaxy.