This image from NASA's Wide-field Infrared Survey Explorer, or WISE, highlights the dust that speckles the Andromeda galaxy's spiral arms. It shows light seen by the longest-wavelength infrared detectors on WISE (12-micron light has been color coded orange, and 22-micron light, red).
The hot dust, which is being heated by newborn stars, traces the spidery arms all the way to the center of the galaxy. Telltale signs of young stars can also be seen in the centers of Andromeda's smaller companion galaxies, M32 and M110.
Andromeda, also called M31, is 2.5 million light-years away, and is the nearest large neighbor to our Milky Way galaxy.
Image credit: NASA/JPL-Caltech/UCLA