Space · Moons

Metis

A moon of Jupiter — Jupiter's innermost moon — orbits inside the synchronous orbit, doomed to spiral inward like Phobos.

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Quick facts

Parent planet

Jupiter

Diameter (mean)

43 km

Mass

1.2 × 10¹⁷ kg
1.6e-06 Moon masses

Mean orbital radius

128,000 km

Orbital period

0.295 Earth days

Discovery year

1979

Discoverer

Stephen P. Synnott (Voyager 2)

Naming origin

Titaness, first wife of Zeus

Surface conditions

Metis is a small, irregular moon 60×40×34 km, orbiting Jupiter at just 128,000 km — well inside Jupiter's synchronous orbital radius. Tidal forces are slowly dragging Metis inward; on geological timescales it will be torn apart by tidal stress or impact Jupiter's atmosphere. Metis is the principal source of dust for Jupiter's main ring.

Missions and observations

Every Jupiter-system mission has had an opportunity to image or characterize Metis. The list below is the Jupiter-system mission catalog; specific Metis encounters are documented in mission archives.

Mission	Year at Jupiter	Status
Pioneer 10 NASA	1973	Completed
Pioneer 11 NASA	1974	Completed
Voyager 1 NASA	1979	Completed
Voyager 2 NASA	1979	Completed
Ulysses NASA/ESA	1992	Completed
Galileo NASA	1995	Completed
Cassini-Huygens NASA/ESA/ASI	2000	Completed
New Horizons NASA	2007	Completed
Juno NASA	2016	Active
Europa Clipper NASA	2030	On the way
JUICE ESA	2031	On the way

Naming etymology

Metis was a Titaness, the first wife of Zeus and goddess of wisdom; Zeus swallowed her when she was pregnant with Athena, who later sprang fully formed from his head. The IAU adopted the name in 1983.

Methodology & sources

Diameter, mass, and orbital parameters from JPL Solar System Dynamics — Physical Parameters. Discovery year and discoverer from the JPL Satellite Discovery Circumstances. Naming etymology from the IAU Working Group for Planetary System Nomenclature. Stylized SVG hero composed from NASA / JPL imagery as visual reference; no photographs are reproduced.