Don’t get too close to that planet

Since tidal forces are much closer to a planet a moon that has an orbit too close to a planet will be pulled apart. This is called the Roche limit and it is about 2.4 times the planet’s radius. Outside that limit the moon can be held together¬†by its own gravitational forces. The rings of Saturn are due to planets that were¬†closer than the Roche limit so they were pulled apart by Saturn’s gravity.

(The Great Courses – Black Holes, Tides, and Curved Spacetime: Understanding Gravity)

2 thoughts on “Don’t get too close to that planet

  1. scott toilet paper coupons

    That’s a good idea. I think the first Halloween I’ll probably go all out just because it’s exciting to me, but after that I’ll probably make them.Plus, store-bought costumes mean a lot of other kids will be wearing the same thing… and the hobo is an adorable idea. =]


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