Why Saturn’s Inner Moons Aren’t Spherical

Why Saturn’s Inner Moons Aren’t Spherical

NASA’s Cassini probe, which just recently ended its 13 year mission by crashing into Saturn, took detailed pictures of Saturn and its moons. It found that some of the inner moons weren’t sphere shaped, but were described as shaped like “ravioli,” according to Google News.

Atlas, the moon that has been described as ravioli shaped, is believed to have been the product of two small “moonlets” smashing into one another creating the strange shape, according to space.com.

While other moons aren’t as peculiar as Atlas, the inner moons, some which lay nearly half the distance to Saturn as our moon does to Earth, are also irregularly shaped. Adrien Leleu, a dynamicist at the University of Bern in Switzerland, theorized that because Saturn has such a high gravitational field, (it’s 95 times the mass of Earth’s) the moons experience tremendous tidal forces, according to space.com.

These tidal forces cause the moons to be formed, not by gradual accumulation of material, but by a series of collisions between other, smaller moons. That is why Atlas, Pan, and Prometheus are described as being shaped like ravioli and potatoes, according to sciencenews.org.

“If that is the case and these bodies formed that way, it has important implications for formations of moons in general, because [previous research has shown] that the pyramidal scenario could be at the origin of most of the moons in the solar system,” Leleu said.

“For bodies such as comets or asteroids, the impact configuration that would form these equatorial ridges have a very low probability of happening,” Leleu said. “But the small moons of Saturn are in a very specific environment — they are very close to Saturn and its rings, and on almost perfectly circular orbits, and almost all in the same plane.”