Saturn is the planet in the solar system with the biggest and more visible rings. The Cassini probe is the most recent one that has been sent to the planet, and we have received lots of information from it. Thanks to different probes sent to Saturn, we know how the planet was formed and the moons it has. They have also studied with precision Saturn’s rings, but we still don’t know exactly how they were formed.
Two not very accepted theories
One of the theories to explain Saturn’s rings formation is that one of its moons, after getting too close to the planet, disintegrated due to the high gravitational forces that Saturn provokes. The remainders of the natural satellite were then disposed in the form of rings around the planet.
Another theory suggests that, when an enormous comet got too close to Saturn, in the same way that happen to the moon in the previous theory, it disintegrated and its leftovers ended by forming the rings.
However, these theories are not viable. This is because the rings are formed by 90 or 95% of ice. If the formation of Saturn’s rings was due to the disintegration of a moon or comet, the composition wouldn’t be the same. On the contrary, the rings would be formed by 50% of ice and another 50% of rocky minerals.
For this reason, the doctor Robin Canup tried to find an alternative solution, that could correctly explain their composition.
The doctor’s Canup explanation
After a certain time of investigations, the doctor Robin Canup arrived at the conclusion that seemed to correspond to reality.
According to the calculations of the scientist, after the formation of Saturn, about 4.5 billion years ago, that planet had various satellites similar to Titan, Saturn’s biggest moon, in size. Due to the high gravitational attraction of the planet, the existing moons of that epoch fell, one after the other, to the depths of the planet (as the latter is a gaseous planet), and only Titan managed to stay in orbit.
During the approach process to the planet, the minor bodies acquired a spiral trajectory and were destroyed. The surface layers of the moons, being frozen and so much lighter than the rocky nuclei, easily detached from the satellites and spread through space. On the contrary, the rocky nuclei, much denser than the upper layers, were absorbed by Saturn. The planets that remained in orbit collected the ice that the previous moon left around the planet, and the cycle repeated another time.
When Saturn absorbed the last of its natural satellites, the latter had converted into an enormous ice ball with a small rocky nucleus. When all this ice detached from the moon, the resulting fragments formed the initial icy planetary belt. The latter had a mass 1000 times bigger than the one of the current rings.
However, after billions of years, most of what existed in the first place was absorbed by Saturn. Another part of the ice, in many collisions against comets and asteroids, many of which were also victims of the gaseous giant.
This theory of doctor Canup also helps us to explain the great quantity of ice that contain some of Saturn’s moons, such as Tetis, which is formed at almost 100% by ice.