The innermost known satellite of Jupiter, distance 128 000 km, orbital period 0.295 days; also known as Jupiter XVI. It lies less than one Jovian radius above the planet’s cloud tops, and within Jupiter’s main ring. Metis is noticeably elongated, 60 × 40 × 34 km. As in the case of Adrastea, particles knocked off the surface of Metis by micrometeoroid impacts probably contribute to the ring. Metis was discovered in 1979 on images taken by the two Voyager spacecraft.