New York Oct 18 (IANS) After poring over NASA s Cassini mission data astronomers have determined that it takes the teamwork of seven moons to keep Saturn s A ring - the largest and farthest of the visible rings - contained.
Without forces to hold the A ring in check the ring would keep spreading out and ultimately disappear.
For three decades astronomers thought that only Saturn s moon Janus confined the planet s A ring.
"Cassini provided detail on the mass of Saturn s moons and the physical characteristics of the rings. So mathematically speaking we concluded that the moon Janus alone cannot keep the rings from spreading out " said lead author of the new research Radwan Tajeddine from Cornell University in New York.
The scientists discovered that confinement of the A ring is shared among the moons Pan Atlas Prometheus Pandora Epimetheus Mimas and Janus.
"All of these moons work as a group to contain the ring. Together they are strong. United they stand " said Tajeddine.
Gravitational pushes by these moons slow the ring down and pull momentum from it according to the findings presented at the at the American Astronomical Society s Division of Planetary Science meeting in Provo Utah.
Cassini which crashed into Saturn on September 15 at the mission s end provided valuable data and detailed images of the planet s rings.
"This was exactly the sort of information we had hoped the Cassini mission would provide and by doing so it has allowed us to solve this puzzle " said Joe Burns Professor at Cornell University.
Scientists are still not sure how the rings formed but the mechanism of their confinement is finally understood Tajeddine said.
"That s the novelty of this idea. No one imagined that the rings were held by shared responsibility " he said.
"The density waves created by moons are beautiful to look at but they actually participate in confining the ring " Tajeddine said.
--IANS
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