ASTR 100Lgx Lecture Notes - Lecture 21: Fighting Network Rings, Orbital Period, Roche Limit
Document Summary
Each individual particle orbits by kepler"s laws, not the whole ring together. Or maybe a comet or asteroid that got ripped apart by saturn"s tidal gravity. Or maybe the leftover material from when saturn formed. Saturn"s rings are inside it"s roche limit, so they"re never forming a moon. The rings are pretty darn thin, some as low as 100 m across. Made up of small particles of water ice and ice-coated rocks. Origin is not known, but thought to be an icy moon colliding with an asteroid. A roche limit is the minimum radius for an orbiting body not to be broken up by tidal gravity. Versus earth it"s got 14 times the diameter, the density, 14 times the mass, similar gravity. It"s spin axis is tilted 97. 86 degrees, so it rotates on its side. Atmosphere has similar composition to j and s, with hydrogen, helium, and a little methan.