Galaxy

Galaxy is a collection of stars, dust and gas held together by gravity. The Milky Way is the galaxy that contains our solar system. Galaxies come in many shapes and sizes but all galaxies have at least one thing in common: they are huge! A typical galaxy has hundreds of billions of stars (and maybe even more) and can contain up to 100 billion times as much matter as our Sun. The visible part of the universe is just a small fraction of what exists since there are so many galaxies out there!

The word galaxy is derived from the Greek galaxias (γαλαξίας) via Latin galaxia "milky" from the Ancient Greek γαλαξός ("milky") or γαλακτόν (galakton), literally "milk-white". Galaxies range in size from dwarfs with just a few billion (or even fewer) stars to giants with one hundred trillion (1014).