New secrets of Saturn’s rings revealed

November 14th, 2007 - 2:27 am ICT by admin  
The findings also suggest that extra mass hiding in the B ring could be much older than previously thought.

The recent sightings include propeller-shaped disturbances in the A ring, one of the two brightest rings.

The first four of these four propeller-shaped structures were discovered in close-up images of Saturn’s A ring in 2006. Since then, many dozens more have been found. They are caused by moonlets as large as Egypt’s Great Pyramid

Now, a team led by Matthew Tiscareno of Cornell University in Ithaca, New York, US, has found many dozens more such disturbances.

According to co-researcher Joe Burns, as the ringed-planet’s strong gravitational pull prevents smaller objects from sticking together to form moonlets so large, they are probably fragments of a kilometre-sized moon.

He said a surprising feature was that the propellers were found only in specific regions of the A ring.

“My gut feeling is that there has been a recent break-up event,” said Burns.

During the course of the research, the team also discovered a number of narrow, slightly elongated rings whose longest axes always pointed at the Sun.

Burns said the tiny particles in these ’sunflower’ rings were somehow pushed around by sunlight. However, electrical charges in the surrounding rings could also play a role, he said.

He said the most surprising new ring result was, however, the obesity of Saturn’s B ring.

Co-researcher Glen Stewart of the University of Colorado in Boulder, US, studied how a star’s brightness varied when the ring passed in front of it.

Observations revealed the existence of very dense dust clumps, implying that the ring was actually three times more massive than expected.

Stewart said if the ring formed through the break-up of a solid body, this object must have been hundreds of kilometres across to account for the observed mass.

“Such massive collisions were more probable in the early days of the solar system, suggesting that the B ring could be very old. The origin of planetary rings is one of the big, unanswered questions of planetary science,” said Larry Esposito from CU Boulder.

“If rings are young, it is only by good luck that we see them now. If they are ancient, rings probably always encircled the giant planets, as they do at the present time. Ancient rings would indicate rings are likely around giant planets detected around other stars,” he said.

Esposito, nevertheless, added that not all of Saturn’s rings were likely to be so primordial.

“A moon or other B ring material could have been recently shattered to make the A ring,” he said.

“It’s an exciting find. But it now becomes much more difficult to explain the brightness of the ring particles, which are expected to be coated by dark meteoritic material over time. The jury is still out on how the rings formed,” said Burns.

Burns presented his study last week at a meeting of the American Astronomocial Society’s Division of Planetary Sciences, reports New Scientist magazine. (ANI)

Related Stories

Tags: , , , , , , , , , , , , , , , , , , ,

Posted in Sci-Tech |