What is a galaxy?

Quick explanation

A galaxy is a clump of stars, held together by gravity.

Small galaxies contain millions of stars, while the most massive ones have billions or even trillions of stars.

But stars are only a small part of a galaxy; besides the gas and star dust lying between the stars, galaxies also consist of dark matter.

The encyclopedia is being re-constructed; until I fix it, you'll have to

  1. do with this old and badly formatted version without nice pictures, or
  2. read one of the articles I did re-format (on redshift or black holes), or
  3. write me and say "Hey, why don't you write a proper article about this topic, because it sounds super interesting!".

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