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.
What Is a Galaxy? | NASA Space Place – NASA Science for Kids
2024年10月11日 · A galaxy is a huge collection of gas, dust, and billions of stars and their solar systems. A galaxy is held together by gravity. Our galaxy, the Milky Way, also has a supermassive black hole in the middle. When you look up at stars in the night sky, you’re seeing other stars in the Milky Way.
Hubble's Galaxies - NASA Science
Thanks to Hubble’s observations, astronomers have traced the evolution and formation of galaxies, discovered that most galaxies contain supermassive black holes, and mapped the presence of the mysterious dark matter that makes up most of the universe’s mass and structure.
Galaxies - HubbleSite
2024年10月28日 · 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.
Webb Unlocks Secrets of One of the Most Distant Galaxies Ever Seen
2024年3月4日 · Initially detected with NASA’s Hubble Space Telescope, this galaxy — one of the youngest and most distant ever observed — is so bright that it is challenging scientists to understand why. Now, GN-z11 is giving up some of its secrets.
What’s a galaxy? All you need to know - EarthSky
2024年5月21日 · A galaxy is a vast island of gas, dust and stars in an ocean of space. Typically, galaxies are millions of light-years apart. Galaxies are the building blocks of our universe. Their...
Galaxy | Definition, Formation, Types, Properties, & Facts | Britannica
6 天之前 · 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.
Galaxies: Collisions, Types and How They're Made | Space
2019年1月4日 · Galaxies are composed of stars, dust, and dark matter, all held together by gravity. They come in a variety of shapes, sizes, and ages.
Galaxies, the cosmic cities of the universe, explained by ... - Space.com
2021年4月22日 · Galaxies are glittering cities, massive metropolises full of stars, dust, gas, black holes, magnetic fields, cosmic rays, dark matter and more. Separated by millions of light-years of essentially...