July 10, 2009—A blue ridge of glowing gas seems to cut through the heart of the galaxy group known as Stephan's Quintet in a newly released picture from NASA's Chandra X-ray Observatory.Discovered in 1877, Stephan's Quintet is really a quartet: Only four of the galaxies (above in a visual-light image by the Canada-France-Hawaii Telescope) lie close together about 280 million light-years away.Astronomers now know that the large spiral galaxy seen at bottom left is actually a foreground object a mere 35 million light-years from Earth.
