Another planet(oid)!

[Az]

http://www.newscientist.com/article.ns?id=dn7758

Cool.

I wonder how many of those Kuiper belt objects are around there, anyway?

[The Viceroy]

IM sure thousands of pluto and below sized planet-(oids) .. the thing is, most of them probably don't come anywhere as near as pluto, and if they are on eliptical orbits, they may only venture close enough to be detected every few thousand years.

[Az]

I don't know why, But I like the little buggers very much.

So now, Quauauauaor, Pluto, Sedna, and this new kid.

cool

[reds4ever]

These new objects being discovered really put Pluto down as a non-planet IMO.

[Az]

How have we defined planet, again? a big spheric lump of matter with a diameter larger than a certain arbitrary size?

Then yes. If we define, say 2000 miles in diamtere. but then Luna is a planet ( I agree with this, btw)

[Krill]

It has to orbit the sun, does it not...

[Az]

a) a sun, not necessarily sol.
b) I don't agree with that, either. I think that if it's pretty huge, round, and isn't a has-been star, or an actual living star, it's a planet.

[Krill]

Our sun is a type two star. The Earth is made from heavy elements that were created from a type one star that went nova or collapsed a while ago. Therefore, according to your opinion we don't live on a planet...

[Az]

by "has been star" I wasn't referring to nova debri, but to white dwarfs, neutron stars, and crap like that.

[reds4ever]

Originally posted by Az
How have we defined planet, again? a big spheric lump of matter with a diameter larger than a certain arbitrary size?

Then yes. If we define, say 2000 miles in diamtere. but then Luna is a planet ( I agree with this, btw)

I would'nt have a definition as such, just take each instance, individually and asses (sp) it.

To me Pluto loses out on it size and it's eliptical orbit.

If Pluto is a planet then why not Charon? they orbit a common centre of gravity that, unlike the Earth and the Moon, is actually outside the larger body.

[Az]

They're a binary planet.

Agreed. while I don't think that the orbit has anything to do with it ( again, I don't like tying planets to circling suns ), Pluto isn't a planet. It's just too damn small.


Btw, previously I stated Sedna is a Kuiper Belt object - this isn't the case.

[chequita guevara]

Luna does orbit the Sun.

[Odin]

Originally posted by Az
How have we defined planet, again? a big spheric lump of matter with a diameter larger than a certain arbitrary size?

Then yes. If we define, say 2000 miles in diamtere. but then Luna is a planet ( I agree with this, btw)

I think the diameter of Mercury is a convenient (if arbitrary) cut-off point, large enough so we don't eventually end up with two dozen Kuiper Belt objects labeled "Major Planets"

[Kuciwalker]

Originally posted by Az
How have we defined planet, again? a big spheric lump of matter with a diameter larger than a certain arbitrary size?

Then yes. If we define, say 2000 miles in diamtere. but then Luna is a planet ( I agree with this, btw)

I'd say that it has to contain within it the center of mass of it and all other objects sharing its orbit - to eliminate moons.

[Vince278]

I thought anything large enough to be spherical under its own gravity and circling a star in its own orbital plane was a planet. This definition excludes comets, asteroids, moons, and Kuiper belt objects.

Kuiper Belt objects, like a large asteroid, has not cleared out its orbital plane (think early Earth). So it is considered part of the belt for now. Pluto is seperate from the belt so it can be considered a planet.

A moon orbits a planet. Many moons can qualify as a planet but they would have to orbit a star instead of a planet.