NASA Studies Starburst Galaxies

394162 03: This montage shows two sets of Chandra X-ray Observatory images (L) and Hubble Space Telescope images (R) of the giant galaxy clusters Abell 2390 and MS2137.3-2353. The clusters are located 2.5 and 3.1billion light years from Earth respectively. The X-ray emission comes from the multimillion-degree gas that fills the clusters. Chandra provides detailed temperature maps for this gas and allows astronomers to precisely determine the masses of the clusters. Most of the mass is in the form of dark matter. (Photo by NASA/Getty Images)