Narrator (Megan Watzke, CXC): This beautiful image gives a new look at Stephan's Quintet, a compact group of galaxies discovered about 130 years ago and located about 280 million light years from Earth. A view in optical light from the Canada-France-Hawaii Telescope on Mauna Kea clearly shows four individual galaxies. A fifth, harder-to-see galaxy is plunging its way through the system at almost two million miles per hour. This extreme motion generates a shock wave that heats the gas between the galaxies. This in turn causes the gas to glow strongly in X-rays, and that's detected by the Chandra X-ray Observatory. Stephan's Quintet provides a rare opportunity for astronomers to observe a group of galaxies in a crucial stage of its evolution.
Revised: July 10, 2009