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 …

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 …

Jan 7, 2026 · 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 …

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 …

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...

Nov 20, 2025 · 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.

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.

Learn about galaxies near and far, from the earliest to form in the distant universe to stunning spirals in our neighborhood.

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 …

Constellations of the night sky A constellation is a grouping of stars that represents one of the 88 divisions of the celestial sphere as defined by the International Astronomical Union. Many …