Galaxies – The “Island Universes”

Abstract

Galaxies are massive collections of stars. In a galaxy like our own Milky Way (shown below), there can be as many as 1011 stars! Other than stars, there is also gas and dust (inter stellar medium), dead star remnants, dark matter and a central super-massive black hole. In the universe, there are estimated to be 1011 such galaxies! One can only imagine how big the universe is!