What is Metis (moon)?
{{Infobox Planet | name = Metis | bgcolour = #a0ffa0 | image = Metis.jpg | caption = Image of Metis was taken by [[Galileo probe|Galileo]]'s solid state imaging system between November 1996 and June 1997. | discoverer = [[Stephen Synnott|S. Synnott]] | discovered = [[March 4]], [[1979]] | mean_orbit_radius = 128,000 [[kilometer|km]] (1.792 R<sub>J</sub>) | eccentricity = 0.0002 | period = 0.294780 d (7 h 4.5 min) | periapsis = 127,974 [[kilometer|km]] | apoapsis = 128,026 [[kilometer|km]] | avg_speed = 31.501 km/s | inclination = 0.06° (to Jupiter's equator) | satellite_of = [[Jupiter (planet)|Jupiter]] | mean_radius = 21.5 ± 2.0 km | volume = ~42,700 [[cubic kilometre|km³]] | mass = 3.6 {{e|16}} [[kilogram|kg]] | density = 0.86 g/cm³ (assumed) | surface_grav = 0.005 [[Acceleration|m/s²]] (0.0005 g) | escape_velocity = 0.012 km/s | rotation = [[synchronous rotation|synchronous]] | axial_tilt = zero | albedo = 0.061 ± 0.003 | single_temperature = ~123 K }} '''Metis''' or '''{{nowrap|Jupiter XVI}}''', is [[Jupiter (planet)|Jupiter]]'s closest moon. Metis was found in 1979 by [[Stephen P. Synnott]] in images taken by the [[Voyager 1]] probe. Its designation was '''{{nowrap|S/1979 J 3}}'''. In 1983 it was named after the mythological [[Metis (mythology)|Metis]], a [[Titan (mythology)|Titan]]ess who was the first wife of [[Zeus]] (the Greek equivalent of Jupiter). Metis is not a [[sphere]] and measures 60×40×34&nbsp;km across. The composition and mass of Metis are not known, but assuming that its mean density is like that of Amalthea (~0.86 g/cm³), its mass can be estimated as ~7×10<sup>16</sup> kg. Amalthea's density implies that moon is composed of water [[ice]] with a [[porosity]] of 10-15%, and Adrastea may be similar. The surface of Metis is very [[crater]]ed. It is dark and appears to be reddish in color. ==Orbit== Metis is the closest moon to [[Jupiter (planet)|Jupiter]]. It orbits Jupiter at a distance of ~128,000&nbsp;km. It has a very small [[orbital eccentricity]] (~0.0002) and [[inclination]] (~