While orbiting Rhea, Saturn’s second largest moon, NASA’s Cassini spacecraft revealed for the first time what appeared to be a ring around the moon. Scientists are still working on the data sent by Cassini after the 2005 flyby, but as it seems, Rhea is surrounded by a broad debris disk, made up of a multitude of particles, with a wide range of sizes, from small pebbles to boulders.

What is most amazing about the possibility of a ring or system of rings surrounding Saturn’s moon is that “until now, only planets were known to have rings, but now Rhea seems to have some family ties to its ringed parent Saturn,” said Geraint Jones, Cassini scientist and lead author of a paper that will appear in the March 7 issue of the journal Science, in a statement.

Scientists are now studying whether the possibility of Saturn’s moon to sustain a system of rings is realistic. With the help of numerical simulations, they’ve managed to establish that Rhea’s gravity field, in combination with its orbiting around Saturn, could sustain a system of rings for long periods of time.

With the help of the six instruments aboard Cassini, designed to study the atmospheres and particles around Saturn and its moons, the spacecraft discovered in the environment around the moon a gradual drop in the number of electrons on either side of it, situation similar to that of Uranus. “Seeing almost the same signatures on either side of Rhea was the clincher,” said Jones. “After ruling out many other possibilities, we said these are most likely rings.”

For the time being, scientists will try to establish the cause for these rings, which could be sign of a collision from an asteroid or comet with Rhea. The discovery brings out yet another amazing thing we didn’t know about our Universe, and that can only make us look forward to what other mysteries are out there.

Image credits: NASA