NASA's new infrared satellite just sent back its first images, including these multi-spectrum wonders depicting Andromeda's bustling star-making activity, and the dent from a long-ago galactic collision.
You can download these images in stunning high quality here. [NASA Mission Page]
Andromeda in a full-spectrum image from NASA's Wide-field Infrared Survey Explorer (WISE) camera.
An image of Andromeda using the shortest-wavelength camera on WISE, which detects infrared light of 3.4 microns. Says NASA, "A pronounced warp in the disk of the galaxy, the aftermath of a collision with another galaxy, can be clearly seen in the spiral arm to the upper left side of the galaxy."
The longest-spectrum image from WISE shows the hot gas of Andromeda's busiest star-making regions. Says NASA, "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."