Quote:
Originally Posted by sjastro
It is based on the Roche limit where the gravitational force on the body is equal to the tidal force on the body. The Roche limit involves a number of factors such as the rigidity of the body, the mass of the Sun and the body, and the radius of the body.
The tidal force is simply the difference in gravitational force exerted on a body. For example the sunlit side of Mercury is subjected to a higher gravitational force than the opposite side which is further away from the Sun (inverse square law).
It is possible for the Roche limit to be inside the Sun for a given body in which case a body will never break up irrespective of how close it is to the Sun.
Regards
Steven
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Thanks for that, very interesting. According to theory, for a rigid spherical body that is more than twice the density of the primary, the Roche limit will be inside the primary. I notice the Roche limit for a solid Earth is 0.8 x Sun's radius but for a fluid Earth it is 1.53 x Sun's radius. (Wikipedia on Roche Limit). There must be some point outside the Sun where a solid body would become fluid due to heat radiation. I wonder how far out this point would be?
Regards, Rob.