Édouard Albert Roche (1820-1883) was a French scientist. 1820 was a leap year starting on Saturday (see link for calendar). ... Events January January 16 - The United States Civil service, is passed January 19 - The first electric lighting system employing overhead wires begins service (Roselle, New Jersey) It was built by Thomas Edison. ...

He is famous for his theory that the planetary rings of Saturn were formed when a large moon came too close to Saturn and was pulled apart by gravitational forces. He also gave his name to both the Roche limit as well as the unrelated concept of the Roche lobe, a useful concept when dealing with the gravitational interaction of a binary star system. A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... The common noun moon (not capitalized) is used to mean any natural satellite of the other planets. ... This article covers the physics of gravitation. ... The Roche limit is the distance within which a celestial body held together only by its own gravity will disintegrate due to a second celestial bodys tidal forces exceeding the first bodys gravitational self-attraction. ... The Roche lobe is the region of space around a star in a binary system within which orbiting material is gravitationally bound to that star. ... A binary star system consists of two stars both orbiting around their barycenter. ...