|Milky Way Galaxy|
Picture of the Milky Way Galaxy in space
|Diameter:||100–180 thousand ly (31–55 kpc)|
|Thickness of thin stellar disk||≈2 thousand ly|
|Number of stars||100–400 Billion (2.5×1011 ±1.5×1011)|
It's a giant galaxy, bigger than most galaxies in its neighbourhood but not as large as the Great Andromeda Galaxy, M 31.  The Milky Way Galaxy is incredibly old and formed not more than about 1 Billion years after the Big Bang and at its centre is an enormous black hole. We don't know if extraterrestrial life or Intelligent aliens are in the Milky Way.