These little moonlets
could be anywhere at this point in time--or even destroyed entirely.
Splat in the sky A smaller companion moonlet
may have long ago smacked into Earth's current moon (as shown at right), a recent study suggests.
These moonlets are likely to be chunks of the ancient body whose break-up produced Saturn's glorious rings," said Joseph Burns of Cornell University, Ithaca, N.
From the number of moonlets spotted in the very small fraction of the A ring seen in the images, scientists estimated the total number of moonlets to be about 10 million.
In contrast, smaller moonlets are not strong enough to clear out the ring, resulting in a partial gap centered on the moonlet and shaped like an airplane propeller.
The Cornell team's extrapolation suggests that the A ring alone houses some 10 million of the 100-m-diameter moonlets.
The gaps and moonlets could offer researchers insights about planet formation in the solar system and around other stars, Spahn says.
In contrast, a smaller moonlet would clear out two short arcs, one on either side of its location.
Cassini imaging scientists analyzing images acquired over the course of about 600 days found the tiny moonlet, half a kilometer (about a third of a mile) across, embedded within a partial ring, or ring arc, previously found by Cassini in Saturn's tenuous G ring.
The discovery of this moonlet, together with other Cassini data, should help us make sense of this previously mysterious ring," he added.
A chunk of material that Cassini has spied in the F ring may be one of those moonlets
, says Joseph Burns of Cornell University.
Both the moonlet
belt objects and the main rings of Uranus have been created by the breakup of larger objects," he says.