Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cassini spacecraft finds evidence of football-field sized moonlets in Saturn’s A ring

31.03.2006


New observations of propeller-shaped disturbances in Saturn’s A ring indicate the presence of four small, embedded moons -- and most likely millions more, Cornell University astronomers report.


Provided
The left image shows the B ring, Cassini Division, A ring and F ring, with the location of the propeller-shaped disturbances indicated. The center image is a closer view of the A ring, showing the radial locations where propeller features were spotted. In the right-hand image, the propellers appear as double dashes in the two close-up images. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. (The horizontal lines in the image represent electronic noise and do not correspond to ring features.)



This is the first evidence of the existence of moonlets bridging the gap in size between the larger ring moons Pan and Daphnis (several miles each in diameter) and the much smaller ice particles that comprise the bulk of the rings. The discovery could lead to a better understanding of the origin and formation of Saturn’s rings and the solar system as a whole.

Matthew Tiscareno, a Cornell research associate, is lead author of a paper describing the discovery in the March 30 issue of the journal Nature.


The four disturbances, which appear as pairs of slightly offset bright horizontal streaks in an otherwise bland region of the ring, were captured in two images taken in 2004 by NASA’s Cassini spacecraft. Astronomers say the streaks are indicators of orbiting moons about 100 meters (328 feet) in diameter: about the length of a football field, but still too small for even Cassini’s highly sensitive Imaging Science Subsystem (ISS) to see directly, but large enough to exert an observable gravitational pull on the particles around them.

"The discovery of these intermediate-sized particles tells us that Pan and Daphnis are probably just the largest members of the ring population, rather than interlopers from somewhere else," said Tiscareno.

A continuum of particle sizes lends strong support to the theory that Saturn’s rings were formed when another object fragmented close to the planet, breaking into pieces which were then captured by Saturn’s gravitational pull.

"There has always been the question about whether the rings were primordial material that was unable to grow into a moon or debris left over from a breakup event," said Joseph Burns, Cornell professor of astronomy and of theoretical and applied mechanics and paper co-author, along with Cornell research associate Matthew Hedman and researchers at other institutions. The discovery doesn’t rule out the accretion model, but "it’s a step in that direction," said Tiscareno. "It’s hard for direct accretion to produce particles this large. It’s much easier if you start with a solid icy core, like a shard from a breakup."

The discovery also helps explain fully cleared openings such as the Encke and Keeler gaps within the rings. The gravitational influence of a larger moon like Pan or Daphnis wraps around the circumference of the rings, creating a gap. The smaller moonlets begin to create this effect, the researchers say, but their influence is not strong enough to prevent particles from falling into the rings ahead of and behind them.

Like a motorboat’s wake on a smooth lake, the four observed disturbances are particularly visible since the area they inhabit is otherwise smooth. But the fact that four were found in just two images covering only a tiny fraction of the ring makes it likely that millions more exist. By studying them further, researchers hope to gain a better understanding of how Saturn’s rings formed -- and even about how solar systems form around stars.

"The structures we observe with Cassini are strikingly similar to those seen in many numerical models of the early stages of planetary formation, even though the scales are vastly different," said Carl Murray, a co-author and astronomer at Queen Mary College, University of London. "In this way, Cassini is giving us unique insight into the origin of planets."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology, manages the mission for NASA.

During its Saturn tour, as currently planned, Cassini will complete 74 orbits of the ringed planet, 44 close flybys of the moon Titan and numerous flybys of Saturn’s other icy moons.

Blaine Friedlander Jr. | EurekAlert!
Further information:
http://www.news.cornell.edu/stories/March06/Tiscareno.Saturn.lg.html
http://www.cornell.edu

More articles from Physics and Astronomy:

nachricht Turning entanglement upside down
22.05.2018 | Universität Innsbruck

nachricht Astronomers release most complete ultraviolet-light survey of nearby galaxies
18.05.2018 | NASA/Goddard Space Flight Center

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: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Self-illuminating pixels for a new display generation

22.05.2018 | Trade Fair News

Embryonic development: How do limbs develop from cells?

22.05.2018 | Life Sciences

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>