The Triangulum Galaxy, M33. This spiral galaxy is located in the triangle-shaped constellation Triangulum, earning it the nickname the Triangulum galaxy. About half the size of our Milky Way galaxy, M33 is the third-largest member of our Local Group of galaxies following the Andromeda galaxy (M31) and the Milky Way. Blue coloured regions scattered throughout the image reveal numerous sites of rapid star birth in M33. The Triangulum galaxy’s orderly spiral structure displays few signs of interactions with nearby galaxies. However, that could change in the future. Only slightly farther away from us than the Andromeda galaxy, about 3 million light-years from Earth, M33 is a suspected gravitational companion to Andromeda, and both galaxies are moving toward our own. M33 could become a third party involved in the impending collision between the Andromeda and Milky Way galaxies more than 4 billion years from now. (NASA)