Edouard Roche

Edward albert Roche (1820- 1883) was born in Montpellier and studied at Montpellier University as a French mathematician and astronomer. His most outstanding performance is in the field of celestial mechanics, and his name is crowned with the concepts of Roche ball, Roche limit and Roche flap.

In history, Edward Roach's most famous theory is about how Saturn's rings are formed. When a huge satellite is too close to Saturn, it will be pulled away by gravity. He described a method to calculate the distance that the gathered objects are torn by tidal force, which is called the Roche limit.

What is the Roche limit?

First of all, literally, this is a limit value about a certain aspect, which refers to the limit value (often referring to the limit of the distance between the two) that a small celestial body is torn by a big celestial body under the tidal force of another celestial body.

In other words, the roche limit is the distance between the gravity of one celestial body and the tidal force caused by the second celestial body. If the distance between two celestial bodies is less than this roche limit value, then the smaller celestial body will tend to split or be "torn", and then become the ring of the parent celestial body.

In "Wandering Earth 2", if the moon falls into the roche limit of the Earth-Moon, it will be torn by a strong gravitational difference when it falls to a certain distance, and it will become many big stars, which will hit the earth at high speed, which will be a disaster to life and the ecological circle on the earth.

Saturn's rings and Roche limit

The ring is the most prominent and obvious planetary ring in planets of the solar system. There are countless small particles in the ring. The main components of these particles are water ice, as well as some dust and other chemicals. According to scientists' research, the reason for the formation of the ring can be explained by roche limit's theory: a planet from outside the solar system moved to the vicinity of the ring, was torn apart by the huge tidal force of the ring, and finally evolved into a ring.