Messier 33 or Triangulum Galaxy is a spiral galaxy located around 3 million light years from Milky Way in the constellation Triangulum. It was discovered by Charles Messier who catalogued it in his catalogue of Nebulae and star clusters as Messier 33. It was not until Edwin Hubble who discovered that it was not a nebula in fact it was a separate galaxy.
About half the size of Milky Way, it is the third largest member in the Local group after Andromeda, and then followed by Milky Way being the second largest. Hubble’s observations reveal that the Triangulum galaxy’s star formation rate is ten times higher than the average found in the Andromeda galaxy.
Fate
You may have heard about the future collision between the Milky Way & Andromeda galaxy which will take place around 4 billion years from now and in next 2 billion years both galaxies will merge to form a single elliptical galaxy. There are two computer simulations about the fate of Triangulum galaxy. One shows that Triangulum galaxy will continue to orbit the newly formed elliptical galaxy while other model shows it becoming part of the collision.