Metis

{{Infobox planet | name = Metis | image = Metis.jpg | caption = Image taken by Galileos Solid State Imager between November 1996 and June 1997 | pronounced = | adjective = Metidian, Metidean | named_after = Μήτις Mētis | discoverer = S. Synnott | discovered = 4 March 1979 | mean_orbit_radius = (1.792 RJ) | eccentricity = | period = | periapsis = | apoapsis = | avg_speed = 31.501 km/s | inclination = 0.06° (to Jupiter's equator) | satellite_of = Jupiter | mean_radius = | dimensions = 60 × 40 × 34 km | volume = | surface_area = | mass = | density = | surface_grav = | escape_velocity = | rotation = synchronous | axial_tilt = zero | albedo = | single_temperature = ≈ 123 K }}Metis , also known as , is the innermost known moon of Jupiter. It was discovered in 1979 in images taken by Voyager 1, and was named in 1983 after the first wife of Zeus, Metis. Additional observations made between early 1996 and September 2003 by the Galileo spacecraft allowed its surface to be imaged. Metis is tidally locked to Jupiter, and its shape is strongly asymmetrical, with one of the diameters being almost twice as large as the smallest one. It is also one of the two moons known to orbit Jupiter in less than the length of Jupiter's day, the other being Adrastea. It orbits within the main ring of Jupiter, and is thought to be a major contributor of material to the rings. Discovery and observations Metis was discovered in 1979 by Stephen P. Synnott in images taken by the Voyager 1 probe and was provisionally designated as '''. In 1983, it was officially named after the mythological Metis, a Titaness who was the first wife of Zeus (the Greek equivalent of Jupiter). The photographs taken by Voyager 1 showed Metis only as a dot, and hence knowledge about Metis was very limited until the arrival of the Galileo spacecraft. Galileo imaged almost all of the surface of Metis and put constraints on its composition by 1998.