Messier 81 & 82: full field
of view of the instrument -1 square degree
Various resolution downloads:
Scientific description:
This sociability has a consequence: at sometime most large galaxies will experience a close encounter with one or more of their neighbours. As the two galaxies fall towards each other under the pull of gravity, tidal forces will distort, even disrupt the common lenticular shape of one or both of the interacting pair. As a result of these forces a huge quantity of material is stripped off the galaxies and flung into intergalactic space. In addition, these interactions often lead to an intense burst of star formation that seems to be triggered as the gas and dust, disturbed by the strong pull of a companion galaxy, is compressed in unusual flows. Here, Messier 81 (bottom) and Messier 82 (top), two magnificent galaxies in the Northern sky, located about 12 million light years away from us, have experienced such event recently. The extremely perturbed appearance of the smaller galaxy is the "smoking gun" that a close encounter has happened. The much larger Messier 81 also shows some clear signs of disturbance. A significant part of one of her spiral arms is stripped away, nearly completely. Astronomers now believe that such stripped material may reassemble into dwarf galaxies of a few hundreds of thousands of stars. Technical description:
Credit line: "Canada-France-Hawaii Telescope / 2003" Copyright © 2003 Canada-France-Hawaii Telescope Corporation |
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