|Discovered by||S. Synnott|
|Discovery date||March 4, 1979|
Mean orbit radius
|128,000 km (1.792 RJ)|
|0.294780 d (7 h 4.5 min)|
Average orbital speed
|Inclination||0.06° (to Jupiter's equator)|
|21.5 ± 2.0 km|
|Mass||3.6 ×1016 kg|
|0.86 g/cm³ (assumed)|
|0.005 m/s² (0.0005 g)|
|Albedo||0.061 ± 0.003|
Metis or Jupiter XVI, is Jupiter's closest moon.
Metis was found in 1979 by Stephen P. Synnott in images taken by the Voyager 1 probe. Its designation was S/1979 J 3. In 1983 it was named after the mythological Metis, a Titaness who was the first wife of Zeus (the Greek equivalent of Jupiter).
Metis is not a sphere and measures 60×40×34 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 ~7×1016 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 cratered. It is dark and appears to be reddish in color.
Orbit[change | change source]
Exploration[change | change source]
The images taken by Voyager 1 showed Metis only as a dot, and very little was known about Metis until the arrival of the Galileo spacecraft. Galileo took pictures of almost all of the surface of Metis and put constraints on its composition.