Using data from NASA’s Chandra X-ray Observatory, ESA’s XMM-Newton, the Giant Metrewave Radio Telescope, and the Apache Point Observatory, astronomers have found that two groups of galaxies in the merging system NGC 6338 are slamming into each other at a whopping speed of about 6.4 millon km/h (4 million mph). The observations also revealed that the cool cores of these galaxy groups are embedded in a large region of shock-heated gas. This composite...