134
| The Moon Was Like Saturn: Why It Looks Different Now
The study suggests that in the distant past, the satellites of the planets of the Solar System may have had rings similar to those of Saturn, but then they disappeared.
No satellite of a planet in the solar system has rings. But scientists have found that such rings could have been created and could have been stable for a million years, even if they were influenced by the gravity of nearby objects. That is, the Moon and other spherical satellites could have had rings, but then they disappeared. Scientists have figured out how this could have happened. The study is published in the journal Astronomy and Astrophysics, writes Live Science.
The most famous planet in the solar system to have rings is Saturn. But Jupiter, Uranus, and Neptune also have rings, although they are not as clearly visible. These rings are made up of pieces of ice and rock of various sizes, and their stability is maintained by the gravity of the so-called shepherd satellites that the four planets mentioned above have.
Scientists have also found rings around some centaurs, asteroids beyond Jupiter, and some dwarf planets. But scientists have never found rings around any known moon of a planet in the solar system.
The authors of the study believe that the physical processes that create rings could theoretically occur on both planets and their moons. Rings could be created from rocky debris thrown off the surface of the moon by an asteroid impact, or from chunks of ice thrown off by cryovolcanoes. Such debris should eventually form a ring under the influence of the moon's gravity. Many moons of planets have cryovolcanoes and have also been hit by powerful asteroids, but they do not have rings.
Scientists decided to find out whether the rings of planetary satellites can be stable at all, that is, not collapse for a very long period of time. Previous results have shown that satellites can have stable rings, but scientists did not take into account the gravitational influence of other satellites and planets.
The authors then selected five sets of spherical moons and their planets, including the Earth and the Moon. In the simulation, each moon was given rings. The results showed that such rings, even under the influence of the gravity of neighboring moons and planets, can remain stable for a million years. The simulation showed that even the Moon could have stable rings, similar to the rings of Saturn. That is, the gravitational influence of neighboring objects over a very long period of time did not destroy these rings, according to the study.
If the moons of the planets in the distant past had rings, where did they all disappear to? Scientists believe that the cause of the destruction of these rings could be the influence of solar radiation, as well as charged particles from the magnetic fields of the planets. On the other hand, there is a possibility that the rings were destroyed by the gravity of the moons themselves, which had ring systems around them.
It turns out that if the Moon did have rings, the debris that make them up fell to the surface of the Earth's satellite a long time ago. And this could also have happened to other satellites of the planets in the Solar System.
