How about we forget about trying to keep Pluto as a planet. Pluto has
significantly lower mass than at least 6 of the solar systems moons and is
part of a large population of bodies (the Kuiper Belt) that includes objects
of similar size to Pluto.

Setting the lower limit of a planet to Pluto's size would put Pluto, UB313
and who knows how many other objects to a higher status than many moons.
This wouldn't be wrong if it wasn't so arbitrary. Setting the lower limit
the minimum mass for sphericity would be impractical because it would
include too many objects.

Therefore I think the mass of the solar system's largest and most massive
moon, Ganymede, (but not its size, that would exclude Mercury) should be set
as the lower limit for the mass of a planet. Anything smaller but still
spherical is a planetoid.


On 26 Sep 2005 21:42:56 -0700, wrote:

|Why not just say that anything smaller than Pluto is just a "Minor
|Planet" and anything Pluto's size or larger is a Planet?