Planet Definition Quotes

If you put Earth out beyond Neptune, you wouldn't be able to call it a planet because it couldn't clear its zone.

I think when people see Pluto revealed by New Horizons, its satellite system, its complex surface, its atmosphere, I think they'll have a hard time saying 'That's not a planet' because it obviously will be, and I think most people are already coming to that opinion anyway, but I think that's really going to drive it home viscerally.

All the nine-planet people out there: Get over it. There's eight.

If you slid Pluto to where Earth is right now, heat from the sun would evaporate that ice, and it would grow a tail. Now that's no kind of behavior for a planet.

What the hell happened to Pluto?!

I'm the one who originally coined the term 'dwarf planet,' back in the nineteen-nineties.

People know a planet when they see one, and I think that's a pretty darn good test, in fact, for planethood.

Why can't Pluto be a planet? Some people like Pluto. And if it doesn't exist then they don't have a favorite planet. Right? Please write back but not in cursive because I can't read cursive.

I refuse to accept Pluto's resignation as a planet.

In the mind of the public, the word 'planet' carries a significance lacking in other words used to describe planetary bodies... many members of the public assume that alleged 'non-planets' cease to be interesting enough to warrant scientific exploration.

Pluto's orbit is so elongated that it crosses the orbit of another planet. Now that's... you've got no business doing that if you want to call yourself a planet. Come on, now! There's something especially transgressive about that.