The Andromeda Galaxy really is just next door as large galaxies go. It’s only about 2.5 million light-years away. So close and spanning some 260,000 light-years, it took 11 different image fields from the Galaxy Evolution Explorer (GALEX) satellite’s telescope to produce this gorgeous portrait of the spiral galaxy in UV light. While its spiral arms stand out in visible light images of Andromeda, the arms look more like rings in the GALEX ultraviolet view, dominated by hot, young, massive stars. The large Andromeda galaxy and our own Milky Way are the dominant members of the local galaxy group.
GALEX was scheduled to be decommissioned, but NASA has transferred operation of the satellite to California Institute of Technology. (CalTech runs JPL for NASA). CalTech will partner with other institutions to keep the satellite doing useful science.
Here’s another UV picture of Andromeda assembled from images taken by NASA’s Swift spacecraft.
Image Credit: NASA