The perfectly picturesque spiral galaxy known as Messier 81, or M81, looks
sharp in this new composite from NASA's Spitzer and Hubble space
telescopes and NASA's Galaxy Evolution Explorer. M81 is a "grand design"
spiral galaxy, which means its elegant arms curl all the way down into its
center. It is located about 12 million light-years away in the Ursa Major
constellation and is one of the brightest galaxies that can be seen from
Earth through telescopes.
The colors in this picture represent a trio of light wavelengths: blue is
ultraviolet light captured by the Galaxy Evolution Explorer; yellowish
white is visible light seen by Hubble; and red is infrared light detected
by Spitzer. The blue areas show the hottest, youngest stars, while the
reddish-pink denotes lanes of dust that line the spiral arms. The orange
center is made up of older stars.
