Here's what happens when galaxies collide - as seen by our Chandra X-Ray Observatory:
M51 is a spiral galaxy, about 30 million light years away, that is in the process of merging with a smaller galaxy seen to its upper left.
This image is part of a "quartet of galaxies" collaboration of professional and amateur astronomers that combines optical data from amateur telescopes with data from the archives of NASA missions.
Image credit: X-ray: NASA/CXC/SAO; Optical: Detlef Hartmann; Infrared: NASA/JPL-Caltech