2.2 Spectra and particle size distribution.

One explanation is that a small moon recently crashed into Himalia and the force of the impact ejected the material that forms the ring. ДЄ ring or ring arc appears to exist close to the moon Himalia's orbit. The age of the ring system is also not known, but it is possible that it has existed since the formation of Jupiter. The total mass of the ring system (including unresolved parent bodies) is poorly constrained, but is probably in the range of 10 11В to 10 16В kg. The halo ring is probably dominated by submicrometre dust. The size of the dust in the rings varies, but the cross-sectional area is greatest for nonspherical particles of radius about 15 Ојm in all rings except the halo. In visible and near-infrared light, the rings have a reddish color, except the halo ring, which is neutral or blue in color. High-resolution images obtained in February and March 2007 by the New Horizons spacecraft revealed a rich fine structure in the main ring. The main and halo rings consist of dust ejected from the moons Metis, Adrastea and perhaps smaller, unobserved bodies as the result of high-velocity impacts. It has four main components: a thick inner torus of particles known as the 'halo ring' a relatively bright, exceptionally thin 'main ring' and two wide, thick and faint outer 'gossamer rings', named for the moons of whose material they are composed: Amalthea and Thebe. The Jovian ring system is faint and consists mainly of dust. Ground-based observation of the rings requires the largest available telescopes. The main ring has also been observed by the Hubble Space Telescope and from Earth for several years. The main ring was discovered in 1979 by the Voyager 1 space probe and the system was more thoroughly investigated in the 1990s by the Galileo orbiter.

The Jovian rings were the third ring system to be discovered in the Solar System, after those of Saturn and Uranus.

The planet Jupiter has a system of faint planetary rings. (In reality, Metis is very slightly closer to Jupiter.) For simplicity, Metis and Adrastea are depicted as sharing their orbit. A schema of Jupiter's ring system showing the four main components.