quilty wrote:

No body in the Solar System is round. I assume that
you'd have to go by some sort of percentage deviation
from a iso-potential surface.


Perhaps he meant "roundish"?


Just off the top of my head, we'd add: Earth's Moon,
Io, Europa, Ganymede, Callisto, Titan, Titania, Triton,
and Charon. If we take it all the way down to Ceres'
size / sphericity it'll be a mess. The big question is,
where's the dividing line and WHY?


Maybe I was just reading between the lines, but I got the impression
that he was going on the principal that planets orbit a star and moons
orbit a planet which orbits said star. That would leave out all of the
moons that you listed.

Since you seem violently against such criteria, what would you suggest
as a criteria for determining whether an object is a planet?

The Sun's gravitational pull on the Moon is greater than the Earth's.
The moon is orbiting the Sun.

--Jeff

--
A man, a plan, a cat, a canal - Panama!

Those who do not learn from history are
doomed to repeat it. --George Santayana

Unthinking respect for authority is the
greatest enemy of truth. --Albert Einstein

Freedom's just another word for nothing
left to lose. --Kris Kristofferson