A galaxy is a physical 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), meaning 'milky', a …

May 5, 2026 · 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 …

Feb 5, 2026 · Discover what a galaxy is explained in simple terms, how many galaxies exist, and how the universe size shapes our view of the cosmos—packed with clear, engaging science.

3 days ago · Galaxies differ from one another in shape, with variations resulting from the way in which the systems were formed and subsequently evolved. Galaxies are extremely varied not only in …

May 29, 2026 · Galaxies coverage from Scientific American, featuring news and articles about advances in the field.

May 16, 2026 · Learn about galaxies, including galaxy types, structure, formation, the Milky Way, dark matter, black holes, and cosmic evolution.

Jun 24, 2026 · Early galaxies were star-forming machines, gobbling up gas and spitting out stars with a furious intensity. A new model helps explain why things were so different back then.

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.

Mar 18, 2026 · 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...

Galaxies are vast cosmic islands of stars, gas, dust, and dark matter held together by gravity. NASA’s space telescopes have revealed intricate details of the shapes, structures, and histories of galaxies …