BrainStuff Classics: Will Saturn's Rings Last Forever?

This so called Grand Finale signaled that the end was nigh for the probe, and on September fifteenth to tenty seventeen, it burned up in the gas giant's atmosphere, bringing a spectacular thirteen years of science in Saturn's orbit to a poignant close. The spacecraft was low on fuel and to avoid an accidental crash into one of Saturn's potentially habitable moons. NASA had long ago decided that the best way to dispose of the mission was to burn it up in

Saturn's upper atmosphere. The agency wanted to avoid earthly contamination on these pristine alien environments. Before its fiery death, however, Cassini took unprecedented measurements of the mysterious ring gap region to reveal some surprising ring dynamics. Though mission scientists expected to detect some wispy elemental gases in this empty region, Cassini's particle instrumentation found a smorgas board of elements and molecules raining from the rings down to the planet's atmosphere.

They estimated around ten tons of material that's about nine thousand kilos is falling onto Saturn from the rings per second. That means that Saturn's rings will eventually disappear and will have existed only for a short blip of s Saturn's four billion year life span. So far, researchers have used Cassini's ring dives to estimate when Saturn acquired its famous rings.

When Cassini zipped through Saturn's ring plane. Mission managers allowed the planet, its rings and moons to gravitationally tug at these speeding spacecraft. These extremely slight tugs resulted in tiny changes in the probe's trajectory which could be precisely measured. Those changes allowed scientists, too, for the first time, make a very good measurement of how much mass is holed

up in Saturn's rings after analyzing the final set of orbits. However, the extent to which Cassini's trajectory was deflected initially didn't make sense. It didn't match the predictions by theoretical models. It turned out the Cassini's motion was being additionally altered by massive flows of material at Saturn's equator, inside its thick atmosphere about six thousand miles or nearly ten thousand

kilometers deep. These massive flows are moving about four percent slower than the visible upper atmospheric clouds, causing a gravitational anomaly that was and predicted Cassini projects. Scientist Linda Spilker of NASA's Jet Propulsion Laboratory said in a statement, the discovery of deeply rotating layers is a surprising revelation about

the internal structure of the planet. The question is what causes the more rapidly rotating part of the atmosphere to go so deep, and what does that tell us about Saturn's interior. However, with this anomaly partially explained, scientists were free to measure the gravitational influence of Saturn's rings and thus measure their mass. The researchers estimate that the total mass of Saturn's rings is approximately forty percent that of

Saturn's moon Mimas. Considering Mimas is two thousand times smaller than Earth's moon, there certainly isn't a lot of material in Saturn's rings. Scientists had previously relied on density waves or ripples through the rings caused by the motion of these sixty two moons in Saturn's orbit to estimate ring mass. Although these estimates were also low, astronomers have always assumed there was some kind of hidden mass in large blocks

of material that remained unseen. Now, at the precision measurements made by Cassini's final orbits, we know that there is no hidden mass. The lower the mass of the rings, the younger they are, and because they are predominantly made of ice, if they were older, the ring material would have become contaminated by interplanetary debris, dulling them, and Saturn's rings,

as we're acutely aware, are beautifully bright. Previous estimates of ring age have been far ranging from four point five billion years the leftovers of when Saturn itself was forming, to a few tens of million years, But with this new finding in hand, it looks like the rings are very young, formed less than one hundred million years ago and perhaps as recently as ten million years ago. Where

the rings came from remains more of a mystery. It's possible that an icy object from the Kuiper Belt or an arrant comet became entwined in Saturn's gravitational field and succumbed to the planet's powerful tides, was ripped apart and eventually ground down to create the banded rings we know and love today. Although Saturn's rings will be gone in a hundred million years, it doesn't mean that our Solar

systems ringed planet days are gone forever. If Saturn can create them, there's little reason why Jupiter, Neptune, or Uranus can't shred and nice the object create another bright ringed planet. Display in the distant future.