Saturn’s Mysterious Rings Might be Debris From a Doomed Ancient Moon
by Pallav Regmi, age 13
The mystery of Saturn’s rings has puzzled humans for centuries. During the 20th century, many astronomers theorized that Saturn’s moons had years ago collided with each other, or with an asteroid, leaving behind debris. This debris then formed Saturn’s characteristic rings. If this hypothesis were true, however, rock particles like those that make up Saturn’s moons would be found in its rings. These moons are about half rock and half ice. More recently, scientists discovered that the rings are 95 percent made of ice. In other words, there is much less rock in the rings than in the moons.
This discrepancy has led to a new theory concerning the formation of Saturn’s rings.
Robin Canup is an astronomer at the Southwest Research Institute in Boulder, Colorado. She recently presented a new theory concerning the origin of Saturn’s rings.
Canup believes that about 4.5 billion years ago, several ice-laden moons were orbiting Saturn. Then, something more than four billion years ago, these large moons were pulled into the huge planet by a disk of hydrogen gas. While the moons were on a collision course with Saturn, the planet’s gravity stripped away the outer layer of ice of each moon. This happened at a point when the moons were still far enough away from Saturn that their massive amounts of ice were forced into orbiting rings. These rings are what we currently see surrounding the planet.
At this early stage the rings that encircle Saturn were 10 to 100 times bigger than they are now. But, over time, the ice has morphed into the tiny inner moons that now orbit Saturn. In essence, large ancient moons were destroyed to make rings that, after billions of years, were made into new moons.
Larry Esposito, a well-known scientist who discovered one of Saturn’s rings said, “I would call it cosmic recycling.”
Many theories have come and gone to explain the origins of the mysterious rings of Saturn. Canup’s theory is fascinating and her work has been well received by the scientific community. A number of leading scientists say the thought that Saturn’s rings are 95 percent ice because the ice was shaved from ancient moons on a collision course with a massive planet makes sense.
[Sources: New York Post; Atlas of the Universe]