Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Recycling of material may extend ring lifetimes

08.12.2003


Although rings around planets like Jupiter, Saturn, Uranus and Neptune are relatively short-lived, new evidence implies that the recycling of orbiting debris can lengthen the lifetime of such rings, according to University of Colorado researchers.



Strong evidence now implies small moons near the giant planets like Saturn and Jupiter are essentially piles of rubble, said Larry Esposito, a professor at CU-Boulder’s Laboratory for Atmospheric and Space Physics. These re-constituted small bodies are the source of material for planetary rings.

Previous calculations by Esposito and LASP Research Associate Joshua Colwell showed the short lifetimes for such moons imply that the solar system is nearly at the end of the age of rings. "These philosophically unappealing results may not truly describe our solar system and the rings that may surround giant extra-solar planets," said Esposito. "Our new calculations of models explain how inclusion of recycling can lengthen the lifetime of rings and moons."


The observations from the Voyager and Galileo space missions showed a variety of rings surrounding each of the giant planets, including Jupiter, Saturn, Uranus and Neptune. The rings are mixed in each case with small moons.

"It is clear that the small moons not only sculpt the rings through their gravity, but are also the parents of the ring material," said Esposito. "In each ring system, destructive processes like grinding, darkening and spreading are acting so rapidly that the rings must be much younger than the planets they circle."

Numerical models by Esposito and Colwell from the 1990’s showed a "collisional cascade," where a planet’s moons are broken into smaller moons when struck by asteroids or comets. The fragments then are shattered to form the particles in new rings. The rings themselves are subsequently ground to dust, which is swept away.

But according to Colwell, "Some of the fragments that make up the rings may be re-accreted instead of being ground to dust. New evidence shows some debris has accumulated into moons or moonlets rather than disappearing through collisional erosion."

"This process has proceeded rapidly," said Esposito. "The typical ring is younger than a few hundred million years, the blink of an eye compared to the planets, which are 4.5 billion years old. The question naturally arises why rings still exist, to be photographed in such glory by visiting human spacecraft that have arrived lately on the scene," he said.

"The answer now likely seems to be cosmic recycling," said Esposito. Each time a moon is destroyed by a cosmic impact, much of the material released is captured by other nearby moons. These recycled moons are essentially collections of rubble, but by recycling material through a series of small moons, the lifetime of the ring system may be longer than we initially thought."

Esposito and former LASP Research Associate Robin Canup, now with the Southwest Research Institute’s Boulder branch, showed through computer modeling that smaller fragments can be recaptured by other moons in the system. "Without this recycling, the rings and moons are soon gone," said Esposito.

But with more recycling, the lifetime is longer, Esposito said. With most of the material recycled, as now appears to be the case in most rings, the lifetime is extended by a large factor.

"Although the individual rings and moons we now see are ephemeral, the phenomenon persists for billions of years around Saturn," said Esposito. "Previous calculations ignored the collective effects of the other moons in extending the persistence of rings by recapturing and recycling ring material."

Esposito, the principal investigator on a $12 million spectrograph on the Cassini spacecraft slated to arrive at Saturn in July 2004, will look closely at the competing processes of destruction and re-capture in Saturn’s F ring to confirm and quantify this explanation. Esposito discovered the F Ring using data from NASA’s Voyager 2 mission to the outer planets launched in 1978.


Contact: Larry Esposito, 303-492- 5990, Esposito@lasp.colorado.edu
Joshua Colwell, 303-492-6805
Jim Scott, 303-492-3114

Larry Esposito | EurekAlert!
Further information:
http://www.colorado.edu/

More articles from Physics and Astronomy:

nachricht Tiny lasers from a gallery of whispers
20.09.2017 | American Institute of Physics

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>