Martian Martian A Martian is a native inhabitant of the planet Mars. Although the search for evidence of life on Mars continues, many science fiction writers have imagined what extraterrestrial life on Mars might be like. Some writers also use the word "Martian" to describe a human colonist on Mars. The earliest known instances of the word "Martian", used as a noun instead of an adjective, were printed in late 1877. They appeared nearly simultaneously in England and the United States, in magazine articles detailing Asaph Hall's discovery of the moons of Mars in August of that year. The next event
Solar System icy objects. Astronomers sometimes informally divide this structure into separate regions. The inner Solar System includes the four terrestrial planets and the asteroid belt. The outer Solar System is beyond the asteroids, including the four giant planets. Since the discovery of the Kuiper belt, the outermost parts of the Solar System are considered a distinct region consisting of the objects beyond Neptune. Most of the planets in the Solar System have secondary systems of their own, being orbited by planetary objects called natural satellites, or moons (two of which, Titan and Ganymede, are larger than the planet Mercury), and, in