This image of the Andromeda Galaxy was taken by XMM-Newton during Christmas 2010. It shows hundreds of X-ray sources within Andromeda, many of them clustered around the centre, where the stars are densest. Each one is a dying star system. The sources can be shockwaves and debris rolling through space from exploded stars or pairs of stars locked in a gravitational fight to the death, in which one strips the other of precious gas.