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?
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(Based on actual events.)
Younger offspring (age 4.5): (singing softly to self while arranging a line of nine grapes on breakfast plate) Nine planets, fine planets, in our solar system. Nine planets, fine planets, go ahead and list 'em ... *
Kepler has discovered 11 new "solar systems" with 26 confirmed planets among them. They:
It seems the IAU ruling on what counts as a planet has stirred a little controversy in the Free-Ride home.
Dr. Free-Ride: (to younger offspring) Could you teach me all the words to your song about the planets.
Younger offspring: It's secret.
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.)