OTD In Space - December 15: Andromeda Galaxy Spotted By Telescope For The 1st Time

On Dec. 15, 1612, the Andromeda galaxy was seen through a telescope for the first time by a German astronomer named Simon Marius. The Andromeda galaxy is the closest major galaxy to the Milky Way, and it can be seen with the naked eye. Early astronomers thought it was a nebula, or a glowing cloud of space dust. Even after Simon Marius saw it through a telescope for the first time, he still couldn't tell that it was actually a galaxy filled with about a trillion stars. It took another three hundred years before Edwin Hubble came along and figured out that it was a galaxy.