Galaxies de Bode et du Cigare

Johann Elert Bode discovered them together in 1774. They attract each other, and that interaction set off a burst of star formation in M82, the Cigar. It runs ten times faster there than in the whole Milky Way. M81 gives up its core and its arms fairly quickly. Two things take hours: the plumes of hydrogen the Cigar throws out on either side of its disc, and the fine dust in M81's arms.

Sources: NASA, catalogue Messier de Hubble, Messier 81, NASA, catalogue Messier de Hubble, Messier 82. A figure wrong? Report it.