(Submitted December 05, 2000)
What is the average size of a galaxy?
Thank you for your question. Our Milky Way galaxy is a pretty typical
large galaxy. Most of the stars are in a disk that is about 100,000
light years across in diameter and 3000 light years thick. Most of the
galaxies in the universe are actually smaller than the Milky Way. For
example, most of the dozens of galaxies in our Local Group are at
least ten times smaller in diameter.
-- Michael Loewenstein and David Marsden
for "Ask an Astrophysicist"