Galaxies and Their Sizes

Part of Scales of the Universe.

Galaxies and their sizes_HERO AMNH/D. Finnin

We live in the Milky Way Galaxy, a disk-shaped galaxy roughly a hundred thousand light-years across and two thousand light-years thick.  The smallest dwarf galaxies are a few percent of that size. The largest galaxies, found at the centers of galaxy clusters, are more than ten times larger than the Milky Way.