Speaker 1: Welcome to brain Stuff from How Stuff Works, Hey, brain Stuff,
Speaker 1: Lauren Vogelbam Here, humanity exists at a very special time
Speaker 1: in our Solar System's history, the era of Saturn's rings.
Speaker 1: In the next hundred million years, Saturn's rings will completely disappear,
Speaker 1: and planetary scientists have realized that it acquired those rings
Speaker 1: only very recently. During the Cassini missions final months at Saturn,
Speaker 1: the NASA spacecraft carried out a series of daring orbits
Speaker 1: through the space between the planet's cloud tops and innermost
Speaker 1: edge of its rings. This so called Grand Finale signaled
Speaker 1: that the end was nigh for the probe, and on
Speaker 1: September it burned up in the gas giant's atmosphere, bringing
Speaker 1: a spectacular thirteen years of science in Saturn's orbit to
Speaker 1: a poignant close. The spacecraft was low on fuel, and
Speaker 1: to avoid an accidental crash into what a Saturn's potentially
Speaker 1: habitable moons, NASA had long ago decided that the best
Speaker 1: way to dispose of the mission was to burn it
Speaker 1: up in Saturn's upper atmosphere. The agency wanted to avoid
Speaker 1: earthly contamination on these pristine alien environments. Before its fiery death, However,
Speaker 1: Cassini took unprecedented measurements of the mysterious ring gap region
Speaker 1: to reveal some surprising ring dynamics. The mission scientists expected
Speaker 1: to detect some whispy elemental gases in this empty region,
Speaker 1: Cassini's particle instrumentation found a smorgas board of elements and
Speaker 1: molecules raining from the rings down to the planet's atmosphere.
Speaker 1: They estimated around ten tons of material that's about nine
Speaker 1: thousand kilos is falling onto Saturn from the rings per second.
Speaker 1: That means that Saturn's rings will eventually disappear and will
Speaker 1: have existed only for a short blip of Saturn's four
Speaker 1: billion year lifespan. So far, researchers have used Cassini's ring
Speaker 1: dives to estimate when Saturn acquired its famous rings. When
Speaker 1: Cassini zipped through Saturn's ring plane, mission managers allowed the planet,
Speaker 1: its rings and moons to gravitationally tug at these speeding spacecraft.
Speaker 1: These extremely slight tugs resulted in tiny change is in
Speaker 1: the probe's trajectory, which could be precisely measured. Those changes
Speaker 1: allowed scientists, too, for the first time, make a very
Speaker 1: good measurement of how much mass is holed up in
Speaker 1: Saturn's rings. After analyzing the final set of orbits, However,
Speaker 1: the extent to which Cassini's trajectory was deflected initially didn't
Speaker 1: make sense. It didn't match the predictions by theoretical models.
Speaker 1: It turned out the Cassini's motion was being additionally altered
Speaker 1: by massive flows of material at Saturn's equator, inside its
Speaker 1: thick atmosphere about six thousand miles or nearly ten thousand
Speaker 1: kilometers deep. These massive flows are moving about four percent
Speaker 1: slower than the visible upper atmospheric clouds, causing a gravitational
Speaker 1: anomaly that wasn't predicted. Cassini Project scientist Linda Spilker of
Speaker 1: NASA's Jet Propulsion Laboratory set in a statement, the discovery
Speaker 1: of deeply rotating layers is a surprising revelation about the
Speaker 1: internal structure of the planet. The question is what causes
Speaker 1: the more rapidly rotating part of the atmosphere to go
Speaker 1: so deep and what does that tell us about Saturn's interior. However,
Speaker 1: with this normally partially explained, scientists were free to measure
Speaker 1: the gravitational influence of Saturn's rings, and thus measure their mass.
Speaker 1: The researchers estimate that the total mass of Saturn's rings
Speaker 1: is approximately that of Saturn's moon Mimus. Considering Mimus is
Speaker 1: two thousand times smaller than Earth's spoon, there certainly isn't
Speaker 1: a lot of material in Saturn's rings. Scientists had previously
Speaker 1: relied on density waves or ripples through the rings caused
Speaker 1: by the motion of the sixty two moons in Saturn's
Speaker 1: orbit to estimate ring mass. Although these estimates were also low,
Speaker 1: astronomers have always assumed there was some kind of hidden
Speaker 1: mass in large blocks of material that remained unseen. Now,
Speaker 1: with the precision measurements made by Cassini's final orbits, we
Speaker 1: know that there is no hidden mass. The lower the
Speaker 1: mass of the rings, the younger they are, and because
Speaker 1: they are predominantly made of ice, if they were older,
Speaker 1: the ring material would have become contaminated by interplanetary debris
Speaker 1: dulling them. In. Saturn's rings, as we're acutely aware, are
Speaker 1: beautifully bright. Previous estimates of ring age have been far
Speaker 1: ranging from four point five billion years the leftovers of
Speaker 1: when Saturn itself was forming, to a few tens of
Speaker 1: billion years, but with this new finding in hand, it
Speaker 1: looks like the rings are very young, formed less than
Speaker 1: one hundred million years ago and perhaps as recently as
Speaker 1: ten million years ago. Where the rings came from remains
Speaker 1: more of a mystery. It's possible that an icy object
Speaker 1: from the Kuiper Belt or an arrant comet became entwined
Speaker 1: in Saturn's gravitational field and succumbed to the planet's powerful tides,
Speaker 1: was ripped apart and eventually ground down to create the
Speaker 1: banded rings we know and love today. Although Saturn's rings
Speaker 1: will be gone in a hundred million years, it doesn't
Speaker 1: mean that our Solar systems ringed planet days are gone forever.
Speaker 1: If Saturn can create them, there's little reason why Jupiter, Neptune,
Speaker 1: or Uranus can't shred anice the object create another bright
Speaker 1: ringed planet display in the distant future. Today's episode was
Speaker 1: written by Ian O'Neil and produced by Tyler Clang for
Speaker 1: iHeart Media and How Stuff Works. For more on this
Speaker 1: and lots other bright topics, visit our home planet how
Speaker 1: Stuff Works dot com. MHM