Saturn’s icy moons, as well as its famous rings may only be hundred million years old, suggesting they formed during the reign of many dinosaurs.
First discovered in the 1600s, astronomers have long debated the age of the moons and Saturn’s rings. To come up with an age, researchers used computer modeling to infer the moon’s past dynamic behavior. Then, they compared present orbital tilts and those predicted by computer simulations to learn how much the orbits of Saturn’s moons have grown.
It turns out that for some of the most important satellites – Tethys, Dione and Rhea – the orbits are less dramatically altered than previously thought. That would suggest that they haven’t crossed many orbital resonances, meaning that they must have formed not far from where they are now and thus are younger than thought.
“Moons are always changing their orbits. That’s inevitable,” Matija Cuk, principal investigator at the SETI Institute who together with Luke Dones and David Nesvorny of the Southwest Research Institute published their findings in the journal Astrophysical Journal, said in a statement.
“But that fact allows us to use computer simulations to tease out the history of Saturn’s inner moons,” Cuk said. “Doing so, we find that they were most likely born during the most recent 2 percent of the planet’s history.”
Researchers had long thought Saturn’s rings were as old as the planet itself. But that thinking changed in 2012, when French astronomers found that tidal effects – the gravitational interaction of the inner moons with fluids deep in Saturn’s interior – are causing them to spiral to larger orbital radii comparatively quickly. The implication, given their present positions, is that these moons, and presumably the rings, are not so old.
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SOURCE: Fox News, Michael Casey