Andromeda VIII
Encyclopedia
galaxy
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
discovered in August 2003. It is a companion galaxy to the Andromeda Galaxy
Andromeda Galaxy
The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years from Earth in the constellation Andromeda. It is also known as Messier 31, M31, or NGC 224, and is often referred to as the Great Andromeda Nebula in older texts. Andromeda is the nearest spiral galaxy to the...
, M31, and evaded detection for so long due to its diffuse nature. The galaxy was finally discovered by measuring the redshifts of stars in front of Andromeda, which proved to have different velocities than M31 and hence were part of a different galaxy.