If you were to pick Saturn out of a lineup you'd probably recognize it by its iconic rings.
They're the biggest, brightest rings in our solar system.
Extending over 280,000 km from the planet; wide enough to fit 6 Earths in a
row. But Saturn won't always look this way. Because its rings are disappearing.
That's right, Saturn is losing its rings! And fast. Much
faster, even, than scientists had first thought. Right now, it's raining 10,000
kilograms of ring rain on Saturn per second. Fast enough to fill an
Olympic-sized pool in half an hour.
This rain is actually the disintegrated remains of Saturn's
rings. Saturn's rings are mostly made up of chunks of ice and rock. Which are
under constant bombardment: Some by UV radiation from the Sun and others by
tiny meteoroids.
When these collisions take place, the icy particles
vaporize, forming charged water molecules that interact with Saturn's magnetic
field; ultimately, falling toward Saturn, where they burn up in the atmosphere.
Now, we've known about ring rain since the 1980s when NASA’s
Voyager mission first noticed mysterious, dark bands that turned out to be ring
rain caught in Saturn's magnetic fields. Back then, researchers estimated the
rings would totally drain in 300 million years. But observations by NASA's
former Cassini spacecraft give a darker prognosis. Before its death dive into
Saturn in 2017, Cassini managed to get a better look at the amount of ring-dust
raining on Saturn's equator.
And discovered that it was raining heavier than previously
thought. With these clearer observations, scientists calculated the rings had
only 100 million years left to live. Now, it's tough to imagine a ringless
Saturn.
But for much of its existence, the planet was as naked as
Earth. While Saturn first formed around 4.5 BILLION years ago, studies suggest
the rings are only 100-200 million years old, tops. That's younger than some
dinosaurs.
So when you think about it, we're pretty lucky we happened
to be around to see those magnificent rings. Really lucky, in fact. Because
efforts to study those rings have led us to other discoveries.
For example, as Cassini explored Saturn's moon Enceladus, it
uncovered a trail of ice and gas leading back to Saturn's E ring. Enceladus is
the whitest, most reflective moon in our solar system.
And by studying the ring more closely, scientists now know
why. Turns out, the moon is constantly gushing out gas and dust.
Some of it ends up in space and in the E ring while the rest
snows back onto the moon's surface, creating a blinding white frost.
So, who knows what other discoveries might be hiding within
the rings? At the very least, it's clear we'd better keep looking while we
still can.