[Sarafan]

http://www.nzherald.co.nz/section/story.cfm?c_id=5&ObjectID=10396493

Really interesting. If we do find more planets around, I'd say we name at least two Capella and Shiva.

[Apathy]

It will mean that astronomy textbooks will have to be rewritten with the names Ceres, Charon and UB313

damn, the old rhymes to remember the 9 planets won't work anymore... and really UB313?! thats not a real name

[aldo_14]

It will mean that astronomy textbooks will have to be rewritten with the names Ceres, Charon and UB313

damn, the old rhymes to remember the 9 planets won't work anymore... and really UB313?! thats not a real name

They were going to call it UB40; the reggae planet.

[Sarafan]

Thats just Reckless, you know.

[karajorma]

I think making Ceres a planet is the real surprise in this one.

I always thought that they'd do the unpopular thing and relegate Pluto instead.

[Fragrag]

Pff, I'm guessing we just want to impress the aliens coming here

[NGTM-1R]

Ceres? It's not even massive enough to round itself off! They can't make that a planet...one of their definitions is it has to be massive enough to assume a spherical form.

[neoterran]

Ceres? It's not even massive enough to round itself off! They can't make that a planet...one of their definitions is it has to be massive enough to assume a spherical form.

You are, of course, wrong. Ceres is Round, and it is massive enough to "round off" as you put it.

http://en.wikipedia.org/wiki/1_Ceres

[NGTM-1R]

No it isn't. I've seen much higher-resolution pictures of it that show it's still rather elongated.

[Eishtmo]

I think they're still debating it.  Though I love this, after all the *****ing and moaning of letting Pluto be a planet, now they've got the idea of not only keeping it a planet, but adding 3 more!  I love it, I really do.

UB313, btw, the discover wants to call Xena.  He is a dork.

[Rand al Thor]

I don't think they'll accept the proposal. I mean it just complicates things unnecessarily. Having different grades of planets based on these four in question seems a bit too much. If they want to do it based on atmosphere, fine, but to invent a whole grading system just to keep pluto in there....? Nah.
Pluto's always been a contended topic so it won't be too much trouble I shouldn't think to reduce it just to a large kuiper belt object. I think the fact that it's orbit, which cuts through that of uranus, is highly eliptical points at it being closer to a large comet than anything else.

[Mars]

All of these "round off" as a function of their own mass, look it up in wikipedia. And really, it's time for a new definition of planet.

[achtung]

If it has a spherical form, then I agree it's a planet.

[Dark Hunter]

Experts sitting on IAU's planet definition committee - composed of astronomers, historians and writers - concluded that in future a planet should be defined as a celestial body that is big enough for its gravity field to form a near-spherical shape.

Not spherical, near-spherical.... and that Ceres definitely is.

[Flipside]

I suspect we wont come up with an efficient way of defining what is a planet and what isn't until we are capabl of geological surveys of them. I would say what defines a planet is based more around how it was made than what it looks like, things like the existence of an atmosphere, magnetic poles etc may help to define it, but I always think it's about how and when it formed as much as how and where it moves.

[neoterran]

Well, that's it... now we really need a Sol : A History update ! (pssst.... Shadow0000) 

[Sarafan]

I suspect we wont come up with an efficient way of defining what is a planet and what isn't until we are capabl of geological surveys of them. I would say what defines a planet is based more around how it was made than what it looks like, things like the existence of an atmosphere, magnetic poles etc may help to define it, but I always think it's about how and when it formed as much as how and where it moves.

Actually aside from the gas giants we can already see and determine the geological structure of them, not in great detail and not 100% exact, but we can.

[Mefustae]

I would say what defines a planet is based more around how it was made than what it looks like, things like the existence of an atmosphere, magnetic poles etc may help to define it, but I always think it's about how and when it formed as much as how and where it moves.

Are you implying we knock Mercury off the list?

[Flipside]

I suspect that the boundaries that define 'planet' will be moved in the future, I think things like 'layered formation' will end up being counted. So a planet cannot be a very worn chunk of something bigger, it has to have formed in the manner of gravitic accumulation of material
Mars, we expect, still follows this 'gobstopper' rule, despite its volcanic inactivity, but although we can tell you the chemical composition of the 'soil', we have no real clue what is going on underneath. Even Mercury, I suspect, would still have evidence of that effect, though I doubt we can ever go there to check. In the case of the Earth and the Moon, our Mantle and the Moon are made of exactly the same material, so logic suggests that the Moon was a part knocked off of the Earth whilst the Mantle was forming. I suspect it would not show the same 'layered' formation as a planet, having being formed in a different manner.

[Mars]

But isn't Titan for instance, not from Saturn? Didn't it form the same way planets do? It's certainly larger than Ceres.