
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 …
Galaxy | Definition, Formation, Types, Properties, & Facts | Britannica
Jan 7, 2026 · Galaxy, any of the systems of stars and interstellar matter that make up the universe. Many such assemblages are so enormous that they contain hundreds of billions of stars. Virtually all …
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 …
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 …
Galaxy Formation and Evolution - Harvard–Smithsonian Center for ...
Galaxies are home to most of the stars in the universe, and they form the beads of the cosmic jewelry that defines structure on the largest scales. But galaxies haven’t always been around, and they have …
Types of Galaxies | Pictures, Facts, and Information
Nov 7, 2025 · Explore the main types of galaxies: spiral, elliptical, barred and irregular with stunning astrophotography and insights into how galaxies form, collide & evolve.
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...
Galaxy - ESA/Hubble
Galaxy A galaxy is a ensemble of stars, dust, gas and dark matter that are bound together by gravity. Galaxies contain anywhere between a few hundred million to a hundred trillion stars. Galaxies are …
Galaxies | Latest Developments in Galaxy Formation and Evolution
Learn about galaxies near and far, from the earliest to form in the distant universe to stunning spirals in our neighborhood.
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 …