Saturn’s rings are disappearing

Saturn’s rings are disappearing quickly, though ‘quickly’ is a relative term. With help from decades-old data from Voyager 1 & 2, NASA scientists have determined that Saturn will lose its iconic rings in less than a few hundred million years. The influence of the planet’s gravity and magnetic field results in a kind of ‘rain’ made from dust and ice particles.

“We estimate that this ‘ring rain’ drains an amount of water products that could fill an Olympic-sized swimming pool from Saturn’s rings in half an hour,” said James O’Donoghue of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “From this alone, the entire ring system will be gone in 300 million years, but add to this the Cassini-spacecraft measured ring-material detected falling into Saturn’s equator, and the rings have less than 100 million years to live. This is relatively short, compared to Saturn’s age of over 4 billion years.” O’Donoghue is lead author of a study on Saturn’s ring rain appearing in Icarus December 17…

Ring particles are caught in a balancing act between the pull of Saturn’s gravity, which wants to draw them back into the planet, and their orbital velocity, which wants to fling them outward into space. Tiny particles can get electrically charged by ultraviolet light from the Sun or by plasma clouds emanating from micrometeoroid bombardment of the rings. When this happens, the particles can feel the pull of Saturn’s magnetic field, which curves inward toward the planet at Saturn’s rings. In some parts of the rings, once charged, the balance of forces on these tiny particles changes dramatically, and Saturn’s gravity pulls them in along the magnetic field lines into the upper atmosphere.

Above, an artist’s rendering depicts how Saturn inner rings may look in the next 100 million years. Read more about the science at NASA.gov.

Then watch these Saturn-themed videos, including Around Saturn: The Cassini program’s incredible images animated, Storm Chasing on Saturn, and Postcards from Saturn: The incredible images that Cassini sent home.