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.
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.
Solar System, Galaxy, Universe: What’s the Difference? - Science@NASA
2017年6月1日 · The universe is all of the galaxies – billions of them! NASA’s telescopes allow us to study galaxies beyond our own in exquisite detail, and to explore the most distant reaches of the observable universe.
Universe - NASA Science
Discover the universe: Learn about the history of the cosmos, what it's made of, and so much more. Worlds beyond our solar system. In 2005, NASA’s Spitzer mapped a ring of dust around Vega, one of the brightest stars in the northern sky.
Galaxy | Definition, Formation, Types, Properties, & Facts | Britannica
2024年12月21日 · 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.
Differences Between the Solar System, Galaxies & the Universe
A galaxy is a massive, gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. The Milky Way Galaxy, which contains our solar system, is home to hundreds of billions of stars, and is just one of the vast number of …
What Is a Galaxy? | NASA Space Place – NASA Science for Kids
2024年12月5日 · 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 is part of our solar system. But where is our solar system?
News & Resources | Night Sky Network - NASA
2013年3月31日 · The universe is all of the galaxies – billions of them! NASA’s telescopes allow us to study galaxies beyond our own in exquisite detail, and to explore the most distant reaches of the observable universe.
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.
Galaxy vs Universe: What’s the Difference? - The Nine Planets
2023年10月31日 · What Is the Difference Between Galaxies and the Universe? The terms universe and galaxy share one common point, they are both terms related to space. Beyond this however the key difference between the two can be compounded by considering a galaxy as an apple and the universe as a fruit bowl.