Galaxy Clusters Abell 222 and Abell 223
ESA's orbiting X-ray observatory XMM-Newton has been used by a team of international astronomers to uncover part of the missing matter in the universe.
10 years ago, scientists predicted that about half of the missing â€˜ordinary' or normal matter made of atoms exists in the form of low-density gas, filling vast spaces between galaxies.
This image shows composite optical and X-ray image of galaxy clusters Abell 222 and Abell 223. The cluster pair is connected by a filament permeated by hot X-ray emitting gas.
The optical image was obtained by SuprimeCam at the Subaru telescope, the X-ray image showing the distribution of the diffuse hot gas (yellow to red) was obtained by XMM-Newton.