--- Kim Hyatt <kimharch@cut.net> wrote:
One could calculate the theoretical limit for becoming spherical, then define any object larger than that limit as a planet, . . .
My two cents - A planet is (1) a non-fusor that orbits a fusor and (2) that has accreted more than 50% of the mass in its orbit. A moon is (1) a non-fusor that orbits a non-fusor planet and (2) that has accreted more than 50% of the mass orbiting a planet and is more than 1% of the total mass of all other moons orbiting the non-fusor planet. A planetiod is (1) a non-fusor that orbits a fusor and (2) that has accreted less than 50% of the mass in its orbit. An asteriod is (1) a (non-fusor that orbits a fusor and (2) that has accreted less than 50% of the mass in its orbit and (3) that is of a mass less than "X", "X" being culturally defined. See also Mike Brown's 2004 discussion of "Is Sedna a planet?" Brown is part of the Kupier Belt hunting team that discovered Sedna and "Xena". His Sedna discussion also reviews using gravitational rounding as a possible criteria. - Canopus56 (Kurt) ____________________________________________________ Start your day with Yahoo! - make it your home page http://www.yahoo.com/r/hs