Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Recycling of material may extend ring lifetimes


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,
Joshua Colwell, 303-492-6805
Jim Scott, 303-492-3114

Larry Esposito | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

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: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>