A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. The word galaxy is derived from the Greek galaxias, literally "milky", a reference to the Milky Way. Galaxies range in size from dwarfs with just a few hundred million …
A fish-eye mosaic of the Milky Way arching at a high inclination across the night sky, shot from a dark-sky location in Chile. The Magellanic Clouds, satellite galaxies of the Milky Way, appear near the left edge.
Photograph of the "Great Andromeda Nebula" from 1899, later identified as the Andromeda Galaxy
Scientists used the galaxies visible in the GOODS survey to recalculate the total number of galaxies.
NGC 3923 Elliptical Shell Galaxy-Hubble Space Telescope photograph