Science
Related: About this forumMoons of Saturn May Be Younger Than the Dinosaurs
March 24 2016 - 9:00 am, PDT
MOUNTAIN VIEW New research suggests that some of Saturns icy moons, as well as its famous rings, might be modern adornments. Their dramatic birth may have taken place a mere hundred million years ago, more recent than the reign of many dinosaurs.
Moons are always changing their orbits. Thats inevitable, says Matija Cuk, principal investigator at the SETI Institute. But that fact allows us to use computer simulations to tease out the history of Saturns inner moons. Doing so, we find that they were most likely born during the most recent two percent of the planets history.
While Saturns rings have been known since the 1600s, theres still debate about their age. The straightforward assumption is that they are primordial as old as the planet itself, which is more than four billion years. However, in 2012, French astronomers found that tidal effects the gravitational interaction of the inner moons with fluids deep in Saturns 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 recent phenomena.
Cuk, together with Luke Dones and David Nesvorny of the Southwest Research Institute, used computer modeling to infer the past dynamic behavior of Saturns icy inner moons. While our own moon has its orbit around Earth to itself, Saturns many satellites have to share space with each other. All of their orbits slowly grow due to tidal effects, but at different rates. This results in pairs of moons occasionally entering so-called orbital resonances. These occur when one moons orbital period is a simple fraction (for example, one-half or two-thirds) of another moons period. In these special configurations, even small moons with weak gravity can strongly affect each others orbits, making them more elongated and tilting them out of their original orbital plane.
By comparing present orbital tilts and those predicted by computer simulations, the researchers could learn how much the orbits of Saturns moons grew. It turns out that for some of the most important satellites Tethys, Dione and Rhea the orbits are less dramatically altered than previously thought. The relatively small orbital tilts indicate that they havent crossed many orbital resonances, meaning that they must have formed not far from where they are now.
http://www.seti.org/seti-institute/press-release/moons-saturn-may-be-younger-dinosaurs
Ichingcarpenter
(36,988 posts)That it changes our whole paradigm in major ways
including the evolution of our planet and the whole solar system?
It opens a big can of worms.
Why did SETI release this story?