Andromedagalaxen

Andromedagalaxen, also known as the Andromeda Galaxy, is a spiral galaxy in the Local Group and the nearest major galaxy to the Milky Way. It lies about 2.5 million light-years away in the constellation Andromeda and spans roughly 220,000 light-years across. The galaxy is estimated to contain around one trillion stars, making it larger in stellar content than the Milky Way. It is typically classified as an unbarred spiral galaxy (type SA(s)b) with a prominent central bulge and two main spiral arms, though its outer disk shows asymmetries from past interactions.

As the dominant member of the Local Group, Andromedagalaxen hosts a system of satellite galaxies, including M32 and M110, along with numerous dwarf spheroidal companions. The center of the galaxy is believed to harbor a supermassive black hole with a mass on the order of tens to a few hundred million solar masses. The arms contain extensive star-forming regions, and the galaxy displays a complex distribution of gas and dust that reflects its dynamic history.

From Earth, the Andromeda Galaxy is visible to the naked eye under dark skies, appearing as a faint elongated patch. It has been observed since antiquity, with a description by the Persian astronomer al-Sufi in 964 CE, and was later recognized as a separate galaxy through modern astronomy. In the contemporary era, Andromedagalaxen is a central object for studies of galactic structure, kinematics, and interactions within the Local Group. It is moving toward the Milky Way at about 110 kilometers per second, and a merger between the two galaxies is expected in several billion years, forming a larger galaxy.