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Jupiter's Main Ring and Inner Satellites
Here the rings and satellites are shown from a side (image above) and from an overhead perspective (right).
Jupiter's four innermost moons supply material for the rings.
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Jupiter's Ring System
This mosaic of Jupiter's ring system was acquired by NASA's Galileo spacecraft when the Sun was behind the planet, and the spacecraft was in Jupiter's shadow peering back toward the Sun.
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Rings
Peering back at Jupiter, while the Sun was hidden behind the planet, the Galileo camera obtained a sequence of images of Jupiter's faint, tenuous rings.
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Jupiter's Main Ring and Halo
Jupiter's ring system has three parts -- a flat main ring; a halo inside the main ring shaped like a double-convex lens; and the gossamer ring outside the main ring.
| Different brightness scales were used to accent different parts of the ring system, one to accent the halo (top) and one to accent the main ring (bottom). In the top view, a faint mist of particles is seen above and below the main ring. This vertically extended "halo" is unusual in planetary rings, and is caused by electromagnetic forces pushing the smallest grains, which carry electric charges, out of the ring plane. |
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Jupiter's Gossamer Ring is the diffuse band which starts exterior to the main ring and continues beyond the left edge of this mosaic. The gossamer rings are much fainter than the main ring and halo (brighter part on right). |
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Gossamer Ring Structure.
New Galileo images, taken at increasing sensitivities, show structure in the gossamer rings. The graphics (bottom of left frame) show the correspondence between the rings and the orbits of the inner satellites. The right frame, a subset of the data in the left frame, focuses on the inner gossamer ring and the moon Amalthea.
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Jupiter's Inner Satellites and the Formation of the Rings.
Fine dust is kicked up as micrometeroids strike the inner satellites. As the dust particles absorb sunlight, they spiral in towards Jupiter and form an equatorial planetary ring. |
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The Heights of Jupiter's Main and Gossamer Rings
correspond to the maximum inclination of the related satellite's orbit from Jupiter's equatorial plane. Thebe's orbit is more inclined than Amalthea's orbit so the outer gossamer ring extends vertically further than the inner gossamer ring. Since both the satellites and the dust particles from them pause at the tops and bottoms of their paths before they come back down, the rings are denser at their top and bottom edges.
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How Jupiter's Ring Halo Forms
| Jupiter's Ring Halo forms as particles which spiral in toward Jupiter are pushed up and down by electromagnetic forces. At certain distances from Jupiter, the vertically oscillating forces and particles' orbital periods become synchronous and the pushing effects are enhanced. These resonances mark the halo's beginning and end. |
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Jupiter's Small Inner Satellites
Jupiter's small inner satellites are irregular in shape due to a history of high velocity, highly energetic impacts from meteoroids, fragments of asteroids and comets. Since these moons are so small, their surface gravities are very low, and the particles kicked up by the impacts easily escape into orbit. |
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