How It Works

What are saturn’s rings made of?

They may not be as interesting as the moons around Uranus but Saturn’s rings do bear further investigation…

Lunar Landscape

Saturn – The Roche lobe causes gravitational forces around Saturn to hold rocky particles

Inner rings – Inner rings are made up of rock particles that never formed into a moon

Outer rings – Outer rings are caused by geysers in the south pole of Saturn

Why does Saturn have rings but other planets do not? The answer has to do with something called the Roche lobe, named after a French astronomer. It seems when a planet orbits around a star (eg our Sun) and that planet has its own orbiting objects (eg a moon), a gravitational pull occurs between the objects. Around Earth, orbiting rocks formed into the moon. On Saturn, the rocks never coalesced and are still orbiting.

Interestingly, the rings are only a few miles in thickness because of the highly localised effects from the Roche lobe. Dr Steve Maran, a noted astronomer, says Galileo was the first to discover the rings, but could not explain them. Today, viewing angles from the Hubble Space Telescope reveal an enormous region extending widely around the planet. There’s also one distinct outer ring, which Maran attributes to geysers emitting from the icy southern polar region on Saturn, leaving a more distinct trail.

  • fabien

    Saturn is not the only planet to have rings. Jupiter, Uranus and Neptune (in the form of an arc) have ring.
    The solar system is evolving, the rings won’t stay around Saturn forever.

  • Robert Stepp

    Some corrections. The rings are mostly made of water ice. The main rings are about 30 feet thick. When viewed edge on, some vertical formations have been seen to pile up in bumps up to 2 miles tall. The rings are being replenished and shepherded by various moons. There is no geyser emanating from Saturn’s south pole or anywhere else on Saturn. This information is taken off of the NASA web site.