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
Further Improvement of Qubit Lifetime for Quantum Computers
09.12.2016 | Forschungszentrum Jülich
Electron highway inside crystal
09.12.2016 | Julius-Maximilians-Universität Würzburg
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine