A planet is a non-nuclear fusing object that has accreted more than 50% of the mass in its orbital track, that orbits an object that is a nuclear fusor. A planetoid is a non-nuclear fusing object that has accreted less than 50% of the mass in its orbital track, that orbits an object that is a nuclear fusor. A moon is is a non-nuclear fusing object that has accreted more than 50% of the mass in its orbital track, that orbits an object that is not a nuclear fusor. These articles may also be of interest - http://www.space.com/scienceastronomy/solarsystem/planet_confusion_001101-1.... http://www.gps.caltech.edu/~mbrown/sedna/#planets - Peace - Canopus56 __________________________________ Do you Yahoo!? The all-new My Yahoo! - What will yours do? http://my.yahoo.com