M101 (aka Pinwheel galaxy) is a face-on spiral galaxy at 21 million light years away in the constellation of Ursa Major. This galaxy is larger than our Milky Way and contains about 1 trillion stars.

M101 (aka Pinwheel galaxy) is a face-on spiral galaxy at 21 million light years away in the constellation of Ursa Major. This galaxy is larger than our Milky Way and contains about 1 trillion stars.