Perseus Perseus In Greek mythology, Perseus (; ) is the legendary founder of Mycenae and of the Perseid dynasty, who, alongside Cadmus and Bellerophon, was the greatest Greek hero and slayer of monsters before the days of Heracles. He beheaded the Gorgon Medusa for Polydectes and saved Andromeda from the sea monster Cetus. He was the son of Zeus and the mortal Danaë, as well as the half-brother and great-grandfather of Heracles. Because of the obscurity of the name Perseus and the legendary character of its bearer, most etymologists presume that it might be pre-Greek; however, the name of Perseus’ native
Andromeda Galaxy Andromeda Galaxy The Andromeda Galaxy (), also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth, and the nearest major galaxy to the Milky Way. Its name stems from the area of the sky in which it appears, the constellation of Andromeda. The 2006 observations by the Spitzer Space Telescope revealed that the Andromeda Galaxy contains approximately one trillion stars, more than twice the number of the Milky Way's estimated 200 to 400 billion stars. The Andromeda Galaxy's mass is estimated to be around 1.76 times that of the