Dont Hurt Me said:Problem is they just never defined a Planet very well, I like to think of Planets as Big enough Rocks to have or had a atmosphere.
Our own moon has an atmosphere, albeit an extremely thin one.CorvusCamenarum said:So what about moons that have atmospheres? Saturn's Titan and Neptune's Triton are the only ones I can recall offhand.
CorvusCamenarum said:So what about moons that have atmospheres? Saturn's Titan and Neptune's Triton are the only ones I can recall offhand.
Lets call em planets Maybe it should be a size thingy, X- amount of mass or larger is a planet. All we have to do is define XCorvusCamenarum said:So what about moons that have atmospheres? Saturn's Titan and Neptune's Triton are the only ones I can recall offhand.
miloblithe said:The biggest surprise to me is Charon. That's a bunch of crap if you ask me.
emw said:The inclusion of Charon makes some sense, in that Pluto and Charon are apparently a "dual-planet" type system, where they orbit each other.
As I understand it, they included Charon because the combined center of gravity is outside of Pluto, which is not the case for any other planet-moon system. But I'm no expert.miloblithe said:But that seems somewhat arbitrary to me. The earth and the moon orbit around eachother too don't they? It's just a matter of ratios. The larger the moon is relative to the planet, the more effect it will have on its motion, but where's the cut off point between moon and planet?
(note: I'm no astronomer, so if I'm missing the point I'm happy to be corrected).
emw said:As I understand it, they included Charon because the combined center of gravity is outside of Pluto, which is not the case for any other planet-moon system. But I'm no expert.
Well, it is 933 km in diameter and contains 25% of the entire mass of the asteroid belt. It's not a small little rock. Some theories suggest it's the core of what was a larger planet (or whatever you'd call it) between Mars and Jupiter.clayj said:This new plan sucks noodles. Ceres as a planet? It's part of the Asteroid Belt, fer cryin' out loud!
Yes... but it seems like you're more saying that it shouldn't be a planet because you weren't raised to consider it as such than because it's small.clayj said:But at 933 km, Ceres is a lot smaller than a lot of the moons that orbit planets... our Moon, Europa, Titan, Io, Triton, Ganymede, Callisto, etc.
Having a clear definition of what a planet is makes everything simpler to define and removes ambiguity moving forward as we discover more of these "things" in our solar system.clayj said:Either leave things the way they are (9 planets), or demote Pluto and make it 8 planets.
Assuming it's not forced on us as part of the hostile takeover process.EricNau said:Then we can just use their system.
Well that would make things even simpler, wouldn't it.emw said:Assuming it's not forced on us as part of the hostile takeover process.