A new study from researchers at the SETI Institute (Search for Extraterrestrial Intelligence) and the Southwest Research Institute (SwRI) has found that most of Saturn’s 62 moons and perhaps even its celebrated rings may only be a hundred million years old. That’s more recent than when dinosaurs were roaming Earth.
One of the study authors, Matija Cuk, principal investigator at the SETI Institute, said he and his team created computer simulations to check into the history of some of the ringed planet’s icy inner moons. Those computer models indicated that they were created ‘sometime during the most recent two percent of the planet’s history.’
Saturn’s rings have been known since Galileo first observed them back in the early 1600’s but scientists still argue about their age. Many assume that the rings are as old as the planet itself, between 4.5 – 4.6 billion years old. But, new research suggests that they, along with Saturn’s moons, were created more recently.
A moon’s orbit can be affected its gravitational interaction – tidal effects – with not only the host planet but with other moons.
To find out when Saturn’s moons were created, the researchers consulted data gathered by NASA’s Cassini mission.
Among the many findings made by Cassini since entering orbit with Saturn in 2004 was the discovery of ice geysers on its moon Enceladus.
By assuming that the moon’s geysers are driven by the energy created by these tidal effects and that the amount of its geothermal activity has always pretty much remained the same, the researchers figured that Saturn’s tides must be pretty strong.
Analyzing this information the team found that it would take Saturn’s tides nearly 100 million years for Enceladus to move from where it was formed to its current location, as it was predicted by the group’s simulations.
This would mean that except for Titan and Iapetus, which are further away, its major inner moons such as Tethys, Rhea, and Dione formed sometime during Earth’s Cretaceous Period, some 66 to 145 million years ago, which is known as the last portion of the “Age of Dinosaurs”.
The researchers add that they think Saturn once had a previous assortment of moons similar to its current inner moons. But they were destroyed when their orbits were disturbed by some event that caused them to smash each other to bits.
“From this rubble, the present set of moons and rings formed,” said Cuk in a press release.”
The researcher’s findings have been published in the Astrophysical Journal.