Whirlpool Galaxy (IMAGE) California Institute of Technology Caption Image of the Whirlpool galaxy, or M51. X-ray light seen by NASA's Chandra X-ray Observatory is shown in purple, and optical light from NASA's Hubble Space Telescope is red, green and blue. The ultraluminous X-ray source, or ULX, in the new Caltech-led study is indicated. Credit NASA/CXC/Caltech/M.Brightman et al.; Optical: NASA/STScI Usage Restrictions Please use credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.