User:Jeremysdelaney

DEFINITION OF A PLANET Planet: A planet is an astronomical body that has undergone whole body differentiation but has not initiated thermonuclear fusion.

The current (2006) definition by IAU is seriously inadequate as it defines ONLY a subset of astronomical constraints but provides NONE of the geological constraints that are needed to define a truly planetary body. It fails to define the essential property of a planet. The IAU definition merely describes the location of one subset of planets in space, it provides no insight into the intrinsic nature of a planet. While the astronomical definition was usable while the planets of the Solar System were effectively inaccessible, that situation has changed dramatically since 1969 (the Apollo 11 landings on the Moon) and planetary bodies have migrated from the astronomical domain into the Geological domain. The working definition of a planet should reflect that current knowledge, not simply historical precedent.