Galaxies - NASA Science
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 smallest can contain a few thousand stars and span just a few hundred light-years.
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 the Milky Way galaxy that contains the Solar System.
Galaxy | Definition, Formation, Types, Properties, & Facts | Britannica
Nov 25, 2024 · 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. Nature has provided an immensely varied array of galaxies, ranging from faint, diffuse dwarf objects to brilliant spiral-shaped giants.
Galaxy Formation and Evolution - Center for Astrophysics
But galaxies haven’t always been around, and they have changed over the universe’s 13.8 billion-year history. Astronomers study the ways galaxies form and evolve by comparing the different shapes across the history of the cosmos, and tracing how they came to look the way they do.
What Is a Galaxy? | NASA Space Place – NASA Science for Kids
What Is a Galaxy? The Short Answer: A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems, all held together by gravity. We live on a planet called Earth that …
What’s a galaxy? All you need to know - EarthSky
May 21, 2024 · Galaxies are the building blocks of our universe. Their distribution isn’t random, as one might suppose. Instead, galaxies reside along unimaginably long filaments across the universe, forming...
Galaxies - HubbleSite
Oct 28, 2024 · Galaxies are vast cosmic islands of stars, gas, dust, and dark matter held together by gravity. Hubble’s keen eye has revealed intricate details of the shapes, structures, and histories of galaxies — whether alone, as part of small groups, or within immense clusters.
Galaxies | Astronomy.com
Galaxies are vast collections of stars, gas, dust, and dark matter bound together by gravity. There are hundreds of billions of galaxies in the universe. The new study suggests that miniture...
Galaxies—facts and information - National Geographic
Apr 17, 2019 · 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 | COSMOS - Swinburne
A galaxy is a gravitationally bound entity, typically consisting of dark matter, gas, dust and stars. Galaxies populate the Universe, mainly residing in clusters and groups. There are thought to be over 100 billion galaxies in the observable Universe.