Jupiterís main ring and halo

Jupiterís main ring and halo

. Jupiterís bright, flat main ring (bottom) is a thin strand of material encircling the planet with an outer radius of 128.94 thousand kilometers, or about 1.8 Jovian radii, located very close to the orbit of the giant planetís small moon Adrastea, at 128.98 thousand kilometers. The brightness of the main ring drops markedly very near the orbit of another moon, Metis. A faint mist of particles, known as the ring halo, surrounds the main ring and lies above and below it (top). The vertically extended halo is unusual for planetary rings, which are normally flattened into a thin plane by gravity and motion. The halo probably results from the ďlevitationĒ of small particles that are pushed out of the main ring plane by electromagnetic forces. These images were obtained from the Galileo spacecraft on 9 November 1996 when it was in Jupiterís shadow, looking back toward the Sun. The rings of Jupiter proved to be unexpectedly bright when seen with the Sun behind them, just as motes of dust or cigarette smoke brighten when they float in front of a light. A third gossamer ring, which consists of two components, is not shown here; it lies beyond the main ring, at greater distances from Jupiter. (Courtesy on NASA and JPL.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University