Lysithea is another small and poorly known satellite. Lysithea was named for a daughter of Oceanus who was one of Zeus's lovers. Although Lysithea is very small, with a radius of only 11 miles (18 km), it was discovered in 1938, before the more precise techniques of modern astronomy were developed.
Beyond Lysithea are Elara and S/2000 J11, both members of the Himalia prograde irregular group. Outside the Himalia group, the remainder of Jupiter's moons are small, poorly known captured asteroids that orbit in a retrograde sense. The Ananke retrograde group has orbits at 145 to 150 degrees to Jupiter's equatorial plane, and the more distant moons have orbits that are that steep or even steeper.
Jupiter has by far the largest known population of moons of any planet in the solar system, almost twice the number of moons of the second contender, Saturn. No doubt a great many additional moons will be added to Jupiter's list over the coming decade, but it is almost a certainty that all will be small captured asteroids with highly inclined and elliptical orbits, a sort of solar system remainder swarm attracted to the giant gravity well of Jupiter. Jupiter's large satellites, including Ganymede, the largest moon in the solar system, display a mind-boggling variety of compositions, appearances, and behaviors, creating a compelling natural laboratory for the study of planetary evolution. The icy Europa and its near neighbor Io form one of the great contrasts in planetary science: They each have new surfaces, caused in Europa's case by floods of ice from its watery interior, and in Io's by floods of unusually hot magma.While Europa is a candidate location for the development of life, Io is an inhospitable place, covered with sulfur, bombarded by Jupiter's magnetic field, and continuously re-covered by magma in volumes far greater than are produced on Earth each year. These moons will no doubt be the targets of future space missions.
Was this article helpful?