Composite image of the interacting galaxies Messier 81 (M81) and Messier 82 (M82). The larger M81 (left) has passed very close to M82 (right) several times in the last few hundred million years. These interactions greatly distorted the shape of M82, which lies only 150,000 light years from M81. M82 is irregular in shape and has pronounced regions of starbirth activity. These galaxies lie around 12 million light years from Earth in the constellation Ursa Major. This image is a composite of data from the Hubble Space Telescope, the Spitzer Space Telescope and the Subaru Telescope at the National Astronomical Observatory of Japan (NAOJ) in Hawaii, USA.