Messier 81 (M81) is a galaxy in the constellation of the Great Bear and is one of the brightest galaxies in the sky. It is located 11.6 million light years from Earth. The Spitzer Space Telescope, NASA Hubble and Galaxy Evolution Explorer have imaged M81 in infrared, visible light and ultraviolet wavelengths, respectively.

Messier 81 (M81) is a galaxy in the constellation of the Great Bear and is one of the brightest galaxies in the sky. It is located 11.6 million light years from Earth. The Spitzer Space Telescope, NASA Hubble and Galaxy Evolution Explorer have imaged M81 in infrared, visible light and ultraviolet wavelengths, respectively.

M81 is similar in structure to the Milky Way. As a spiral galaxy, M81 has aging stars in its long, curved arms. At the centre of the galaxy is a black hole 15 times the size of the Milky Way's black hole Sagittarius A*.

The image shows purple, blue, yellow, white, red, white, orange, yellow, white, red and orange spots spreading out around the long curved arms of M81. The blue colour represents the young and hot stars detected by the Galaxy Evolution Explorer. The yellowish-white colour represents visible light seen by Hubble, while the red dust bands were detected at infrared wavelengths.