IMO I would look at other factors to determine if something is a planet or not. I think having an atmosphere is not a good requirement seeing how our
own mercury has none. Surface activity is irrelevent (just my opinion) and moons... I think we can't go by that either. Mercury and Venus have no
moons.
What does constitute a planet?
I think first off that it must be orbiting a sun and be in its own orbit. To clarify, I think that anything orbiting within a belt of
asteroids cannot be included as a planet. This includes the Kuiper Belt and this larger than Pluto "Xena". So I am also saying that I don't think
Pluto should be classified as a planet since it is also in the Kuiper belt.
I think a second factor should be gravity. I think that the gravity of the orbiting mass should be great enough to pull the object into itself thus
creating a spherical shape.
Here is another article on this "Xena" from discovery news
dsc.discovery.com...
BTW, I don't like the name Xena; who comes up with these names?




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