Saturn's rings might be sitting pretty right now, but eventually they're gonna go. And we've narrowed it down to three spectacular possible fates, the last of which might actually be pretty cool to watch.
A lot of people have been moved by the sight of Saturn's rings. Galileo described them, when he first saw them, as metaphorical "ears." Another astronomer and theologian, Leo Allatius, thought they might literally be Jesus' foreskin (really). Most of us today just think of them as pretty. It's likely that they were formed when a moon or two was destroyed and fragments of it spread out, orbiting the planet spectacularly. The moon was probably like Enceladus, covered with ice. Many of the rings are white, with minor impurities in the ice turning them delicate shades of blue and pink.
If there's one thing that the universe hates, it's delicate pastels, and so it's natural that Saturn's rings aren't going to last. The only question is, how cool is it going to look when they go? The most simple and boring way for them to go is the most likely. The orbits of the debris will degrade, causing them to either plunge into the planet or fly off into space. From Earth it'll look like they're evaporating very slowly. Yawn.
A more exciting theory is they'll get worn away by comets. This might sound like the same thing, but spacecraft have observed orbiting moons causing visible waves and collisions in the rings. There's even been footage of sudden tears and gaps as objects plow into the rings, disrupting whole sections with their gravity. Seeing comets and meteors taking out huge sections of the rings would be a little like seeing whole stacks of dominoes fall with one touch.
The coolest way for Saturn's rings to go, though, would be if they stuck around long enough for the sun to expand. If more debris gets sucked into them, they might last that long. In order to see the event, humans would either have had to move to Mars or go live aboard spacecraft, but it would be worth it. Since Saturn's rings are mostly ice, they benefit from having the sun a good distance away. As the sun heats and expands, the debris in the rings would heat up massively. Although the heat and movement in the rings would dismantle them, they would keep trying to orbit the sun along with Saturn... for a while, anyway. They'd heat up, giving off light, and trail along behind Saturn, turning Saturn into the largest "comet" this solar system has ever seen.
This is yet another reason to keep the Earth livable while terraforming other planets. We do want to be around to see this.
Top Image: NASA/Hubble
Second Image: NASA