This striking view of the Cartwheel Galaxy is a composite of GALEX (blue), Hubble Space Telescope (green), Spitzer Space Telescope (red) and Chandra X-ray Observatory (purple) images. The outer ring, which could encircle our Milky Way Galaxy, appears blue and violet. Pink clumps along the outer ring show X-ray and ultraviolet sources occuring together. Astronomers think they're collections of binary-star systems containing black holes or neutron stars. The Cartwheel's inner ring and nucleus appear yellow-orange because they emit primarily at visible and infrared wavelengths. The newly discovered extended disk is not visible in this composite.
NASA/JPL/CALTECH