One of the brightest galaxies in planet Earth's sky is similar in size to
our Milky Way Galaxy: big, beautiful M81. This grand spiral galaxy can be found toward the northern constellation
of the Great Bear (Ursa Major). This superbly detailed view reveals M81's bright yellow nucleus, blue spiral arms, and sweeping cosmic
dust lanes with a scale comparable to the Milky Way. Hinting at a disorderly past, a remarkable dust lane actually runs
straight through the disk, to the left of the galactic center, contrary to M81s other prominent spiral features. The errant dust lane may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82. Scrutiny of variable stars in M81 has yielded one of the best determined distances for an external galaxy -- 11.8 million light-years.