London: A new study has suggested that Saturn`s rings may have been formed after the death of an early Titan-sized moon whose upper layers were ripped off as it spiralled into the infant Saturn.
Planetary scientist Robin Canup of the Southwest Research Institute said that one of the problems in working out where Saturn`s rings came from is their composition, reports Nature.
The rings are 90 percent-95 percent water ice-odd because the primordial solar system would have been comprised of about equal parts ice and rock.
Furthermore, the rings have been collecting interplanetary dust ever since they were formed.
"So they must have formed as essentially pure ice," she said.
Prior theories suggested that the rings were produced by the break-up of a small moon that fell too far into Saturn`s mammoth gravity or by the breakup of a very large comet that suffered the same fate.
Canup`s hypothesis is that the rings were formed when a Titan-sized moon with a rocky core and an icy mantle spiralled into Saturn early in solar system history.
Tidal forces ripped off part of the icy mantle, distributing it into what would become the rings. But the rocky core was made of tougher stuff.
"It hits the planet`s surface before it disrupts. The end result is a pure ice ring," she said.
Afterward, some of that ice recondensed into new moons, she added.
But due to changes in the evolving Saturn system, these "spawned" moons now spiralled outward rather than inward.
Joseph Burns, a planetary scientist from Cornell University said: It is a very clever new idea. One of the things it can do is produce rings made out of quite pure water ice, which has been a problem in the past."
If Canup`s theory is correct, Saturn would originally have had a ring much more massive than it is now. That would mean the ring contained enough material to spawn icy moons like Enceladus, Dione and Tethys.
The findings were presented at a meeting of the American Astronomical Society`s Division for Planetary Science in Pasadena, California.