in the constellation Ursa Major
7 million times the mass of the Sun
Diameter roughly 30 million miles (45 million km), about 30 times the diameter of the Sun.
This view of M81, obtained by a telescope aboard a space shuttle mission, shows the galaxy in both visible (red and yellow) and ultraviolet (blue) wavelengths. The blue regions are much hotter than the others, and outline the galaxy's spiral arms and its nucleus. The nucleus may contain a supermassive black hole. [NASA/UIT]
This document was last modified: October 24, 2005.