Messier 81 and 82

The two galaxies Messier 81 and Messier 82 lay close to each other (visually) in the constellation Ursa Major. Messier 81 on the right is a spiral galaxy, 8.5 million light years away. It has a diameter of around 90'000 light years, which makes it a little bit smaller than out milkyway galaxy.

On the left side lays Messier 82, a star burst galaxy. It has very prominent and shining red dust clouds. Those dust clouds are made up of hydrogen, which shines red when it gets ionised. Due to the galaxy’s high concentration in hydrogen, it is a very active place for star birth. Interactions with its big neighbor Messier 81, caused waves of star bursts in Messier 82. This way stars of a total mass of ~10 solar masses were born every year.