Messier 81, also known as Bode's Galaxy, is a spiral galaxy located in the constellation Ursa Major. It is approximately 12 million light-years away from Earth and has a diameter of about 90,000 light-years. This galaxy is notable for its bright core and well-defined spiral arms, making it a popular target for amateur astronomers. Messier 81 is part of a group of galaxies that includes Messier 82, a nearby starburst galaxy. The two galaxies are interacting gravitationally, which can influence their shapes and star formation rates. Messier 81 is also cataloged as NGC 3031 in the New General Catalogue.