NANTES, France, Oct. 10 (UPI) -- A comet colliding with Saturn six centuries ago left "footprints" on the planet's rings still visible today, a U.S. researcher told a scientific conference.
Essam Marouf, from San Jose State University, says the disintegrating comet dropped dusty clouds of debris on the giant planet's iconic rings, creating rippled footprints detected by the orbiting Cassini spacecraft, ScienceNews.org reported.
Marouf discussed the findings during a joint meeting of the European Planetary Science Congress and the American Astronomical Society's Division for Planetary Sciences in Nantes, France.
Marouf, a member of the Cassini science team, told how the probe sent radio waves back to Earth through a part of Saturn's innermost ring system, revealing a "very unusual kind of addition" to the normal ring structure.
"There were highly regular little wiggles that rippled over hundreds of kilometers in a very specific pattern," Marouf said.
A similar structure in Jupiter's rings detected by the Galileo probe orbiting that planet were traced to debris littered by comet Shoemaker-Levy 9 as it crashed into the planet in 1994.
Data gathered from the ripples in Saturn's rings allowed astronomers to date the comet impact.
"They date back to about the late 1300s," Marouf said. "And there is very clear evidence for two events, not one, separated by about 50 years."
