These results support the possibility that Saturn’s rings formed billions of years ago, perhaps at the time when giant impacts excavated the great basins on the Moon. The findings also suggest that giant exoplanets may also commonly have rings.
Dr Larry Esposito, Principal Investigator of Cassini’s UVIS instrument, will be presenting the results at the European Planetary Science Congress in Münster on Tuesday 23rd September.
“Both Cassini observations and theoretical calculations can allow the rings of Saturn to be billions of years old. This means we humans are not just lucky to see rings around Saturn. This would lead us to expect massive rings also to surround giant planets circling other stars,” said Dr Esposito.
Esposito’s colleagues at the University of Colorado, Glen Stewart and Stuart Robbins, have computed the gravitational attraction and collisions between more than 100,000 particles, representing a sample of those in Saturn’s rings. They followed the orbit and history of each individual particle, and calculate the amount of starlight that would pass through the ring. These results have been compared to Cassini observations of starlight blocked by the rings, which has traditionally been used to estimate the total amount of material in the ring system. Esposito used this method in 1983 to estimate that rings of Saturn contain as much material as Saturn’s small moon Mimas, which is about 250 miles across. The new simulations show Saturn’s ring particles aggregate into clumps, which would lead to the previous estimate being low by a factor of 3 or more.
Calculations by Esposito and his student Joshua Elliott show that meteorites slowly grind and shatter the particles in the ring. Gradually, a layer of dust and fragments builds up and covers each particle. This layer includes both ice (from the particle) and meteoritic dust. As time passes, the ring system is more polluted and darkened by meteoritic dust.
Because the rings appear so clean and bright, it was argued that the rings of Saturn were much younger than Saturn, which is some 4.5 billion years old. It was calculated from Voyager measurements that the rings are only about 100 million years old, approximately as ancient as when dinosaurs inhabited the Earth. The new calculations show that if the rings are more massive, they appear less polluted, and thus could be proportionately older. Recycling of ring material extends their lifetime and reduces the expected darkening.
One problem with this proposal for more massive and ancient rings is that the Pioneer 11 space mission to Saturn in 1979 measured the ring mass indirectly by observing charged particles created by cosmic rays bombarding the rings.
“Those mass estimates were similar to the ones from Voyager star occultations, apparently confirming the previous low mass value. However, we now recognize that the charged particles are double-valued. That means they could arise from either a small or large mass. We now see that the larger mass value could be consistent with the underestimates due to ring clumpiness,” said Dr Esposito.
Anita Heward | alfa
Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)
Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences
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...
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...
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...
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...
'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...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences