The Milky Way, known by many other names by the various indigenous species, is an SBc class galaxy. The Milky part of its name is derived from its appearance as a dim glowing band arching across the night sky. The term "Milky Way" is a translation of the Latin via lactea, from the Greek γαλαξίας κύκλος (galaxías kýklos, "milky circle"). The name "Via Lactea" its still used by speakers of Romance languages to call the Milky Way, being an alternative name for this Galaxy even today.The diameter of the Milky Way from end to end is roughly 126,000 light years. The Milky Way contains over 400 Billion stars, the majority of which have planetary systems. The Sol System is located within the Milky Way disk, about 27,000 light-years from the Galactic Center, on the inner edge of one of the spiral-shaped concentrations of gas and dust called the Orion Arm. At the center of the Milky Way there exists a supermassive black hole known as Sagittarius A.