The Cassini probe has spotted meteoroids crashing into Saturn’s rings for the first time, breaking up into rubble streams in the process.
It’s been known for some time that meteoroids often impact the rings of planets in the solar system, but previously we hadn’t caught them in the act.
Nasa studied five impact events between 2009 and 2012, showing clouds of material being ejected as a result. An equinox in the summer of 2009 meant that the Sun was at a very shallow angle to the rings, allowing the debris clouds to stand out against the darkened rings.
“We knew these little impacts were constantly occurring, but we didn’t know how big or how frequent they might be, and we didn’t necessarily expect them to take the form of spectacular shearing clouds,” said Matt Tiscareno, lead author of a paper describing the results in Science.
“The sunlight shining edge-on to the rings at the Saturnian equinox acted like an anti-cloaking device, so these usually invisible features became plain to see.”
The implications of the research suggest that meteoroids of this size — a centimetre to several metres — break up when they first encounter the rings, creating smaller pieces that then orbit the gas giant.
These new results imply the current-day impact rates for small particles at Saturn are about the same as those at Earth — two very different neighbourhoods in our solar system — and this is exciting to see,” said Linda Spilker, Cassini project scientist at Nasa’s Jet Propulsion Laboratory.
“It took Saturn’s rings acting like a giant meteoroid detector — 100 times the surface area of the Earth — and Cassini’s long-term tour of the Saturn system to address this question.”