Colbert thrashes the new planets. Neil de Grass Tyson, Astrophysicist and Director, Hayden Planetarium, of New York City is on the show. A planet is something that's round?
Ok, so does "Sharon" (Or is it Charoon, after the Greek boatsman?..), previously considered Pluto's moon, orbit the Sun, Pluto, or both (making it a double-planet system)? Anyway you see it, the same applies for our (or should I say America's) moon, and any other moon. There's no clean cut, it's a continuum, and there will always be arbitrary decisions about that.
(Maybe the definition could be reconstructed so that the point the two "planets" revolve around has to be outside the perimeter of both planets. somewhere in between. I don't know if this is the case for Pluto and Charoon.)
I think it's a great definition. Something that orbits a star, not another planet, and that's gravity has collapsed its structure to be round.
It's better than "a planet is whatever we arbitrarily decide in some meeting at some point", which is more or less the current definition.
;)
Ok, so does "Sharon" (Or is it Charoon, after the Greek boatsman?..), previously considered Pluto's moon, orbit the Sun, Pluto, or both (making it a double-planet system)? Anyway you see it, the same applies for our (or should I say America's) moon, and any other moon. There's no clean cut, it's a continuum, and there will always be arbitrary decisions about that.
(Maybe the definition could be reconstructed so that the point the two "planets" revolve around has to be outside the perimeter of both planets. somewhere in between. I don't know if this is the case for Pluto and Charoon.)