The rings are raining down onto the planet, and disappearing surprisingly fast.
4.5 billion years ago, our Solar System first formed.
Arising from a protoplanetary disk, many young protoplanets resulted in 8 long-term survivors.
After billions of years of cosmic evolution, Saturn stands out from the rest.
While all gas giants possess ring systems, Saturn’s is uniquely large, prominent, and brilliant.
Made of 99% water-ice, nobody knows where they originated from.
Perhaps they’ve always existed, with gravitation creating clumps while tidal forces and collisions break them up.
Alternatively, perhaps they arose from a moon-destroying collision.
Others have suggested an origin from captured asteroids and comets.
Irrespective of their creation, these rings are nearing the end of their lifespan.
NASA’s Cassini mission revealed Saturn, up close, as never before.
Near mission’s end, it repeatedly passed between the main rings — including through ring gaps — and the planet.
What it found was shocking: a massive “rainstorm” of atoms and molecules.
Those molecules included hydrogen, water, ammonia and hydrocarbons, among others.
Overall, 10 tonnes of ring matter rain down onto Saturn with each passing second.
Based on the observed rate, Saturn’s rings will completely disappear within 300 million years, at most.
Across the Universe, ringed planets may only be transient rarities, after all.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.