Tags: Galaxy.
NGC 7331 (also known as Caldwell 30) is a spiral galaxy about 40 megalight-years (12 Mpc) away in the constellation Pegasus. It was discovered by William Herschel in 1784. NGC 7331 is the brightest member of the NGC 7331 Group of galaxies.The galaxy is similar in size and structure to the galaxy we inhabit and is often referred to as the Milky Way’s twin although recent discoveries regarding the structure of the Milky Way may call this similarity into doubt.