Jupiter's fifth largest moon, Amalthea, is heavily cratered and red in colour. It is thought Amalthea gets its colour from the sulphur spewed into space by the volcanoes on Io, another of Jupiter's moons.
First seen by Edward Barnard in 1892, Amalthea was the last moon to be discovered by direct visual observation through a telescope.
Photo: Amalthea taken by the Galileo probe (NASA/JPL)
Jupiter's moon is the reddest object in the Solar System.
Sir Patrick Moore is amazed by the detail of Voyager 1's images.
Early in Voyager 1's mission, Sir Patrick Moore and his guest Dr Garry Hunt of University College London discussed some of the probe's findings, which included a ring around Jupiter and images of Jupiter's moons Amalthea, Callisto, Io, Europa and Ganymede. Since Sir Patrick and Dr Hunt spoke, Jupiter has been found to have three faint rings.
Amalthea (// am-əl-THEE-ə; Greek: Αμάλθεια) is the third moon of Jupiter in order of distance from the planet. It was discovered on September 9, 1892, by Edward Emerson Barnard and named after Amalthea, a nymph in Greek mythology. It is also known as Jupiter V.
Amalthea is in a close orbit around Jupiter and is within the outer edge of the Amalthea Gossamer Ring, which is formed from dust ejected from its surface. From its surface, Jupiter would be an astonishing sight in its sky, appearing 46.5 degrees in diameter.[b] Amalthea is the largest of the inner satellites of Jupiter. Irregularly shaped and reddish in color, it is thought to consist of porous water ice with unknown amounts of other materials. Its surface features include large craters and ridges.
Amalthea was photographed in 1979 and 1980 by the Voyager 1 and 2 spacecraft, and later, in more detail, by the Galileo orbiter in the 1990s.