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 25, 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...

Jan 18, 2024 · Galaxies are among the largest and most beautiful objects in the night sky. These huge swirling masses are where almost every star in the Universe is born, lives and dies.

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 …

Mar 23, 2025 · Typically, galaxies are millions of light-years apart. Galaxies are the building blocks of our universe. Their distribution isn’t random, as one might suppose. Instead, galaxies reside along...

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

In this chapter, we start our exploration of the vast realm of galaxies. Like tourists from a small town making their first visit to the great cities of the world, we will be awed by the beauty and variety of the …