
Galaxy - Wikipedia
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity. [1][2] The word is derived from the Greek galaxias (γαλαξίας), literally 'milky', a reference to …
Galaxies - NASA Science
May 2, 2025 · Galaxies consist of stars, planets, and vast clouds of gas and dust, all bound together by gravity. The largest contain trillions of stars and can be more than a million light-years across. The …
Galaxy | Definition, Formation, Types, Properties, & Facts | Britannica
Nov 27, 2025 · The existence of galaxies was not recognized until the early 20th century. Since then, however, galaxies have become one of the focal points of astronomical investigation. The notable …
What Is a Galaxy? - Scientific American
May 9, 2025 · Huge clouds of invisible dark matter accumulated regular matter (in the form of gas) via gravity, which eventually collapsed to form galaxies and the stars in them.
Galaxies—facts and information | National Geographic
Galaxies are sprawling systems of dust, gas, dark matter, and anywhere from a million to a trillion stars that are held together by gravity. Nearly all large galaxies are thought to also contain...
What is a Galaxy? - sciencenewstoday.org
Mar 19, 2025 · Galaxies are the grand islands of the universe, each one a vast metropolis of stars, gas, dust, dark matter, and endless possibility. From tiny dwarfs to sprawling giants, galaxies tell the story …
13: Galaxies - Physics LibreTexts
This page explains that galaxies are vast systems made up of stars, remnants, interstellar medium, and dark matter, named after the Greek word for milk. There are approximately 170 billion galaxies in the …
What is a galaxy? - BBC Sky at Night Magazine
Jan 18, 2024 · Galaxies are among the largest and most beautiful objects in the night sky. These huge swirling masses are where almost every star in the Universe is born, lives and dies.
Galaxies | NASA's UoL
Galaxies are vast cosmic islands of stars, gas, dust, and dark matter held together by gravity. NASA’s space telescopes have revealed intricate details of the shapes, structures, and histories of galaxies …
List of galaxies - Wikipedia
This is a list of galaxies that are well known by something other than an entry in a catalog or list, or a set of coordinates, or a systematic designation.