Breaking news here! A giant Kuiper Belt object has been discovered 97 a.u. from Earth and Sun, definitely larger than Pluto:

http://SkyandTelescope.com/news/article_1560_1.asp

Preprint article that will present further details of the planetoid and its moon at the American Astronomical Society's planetary sciences meeting in Cambridge, UK, on 8 September is available here (pdf file, 113kb).

That preprint is about the wrong Kuiper Belt object! Just to keep things confusing, TWO big KBOs were announced today. The one with a satellite is 2003 EL61. The one that's bigger than Pluto is 2003 UB313.

Preprint article that will present further details of the planetoid and its moon at the American Astronomical Society's planetary sciences meeting in Cambridge, UK, on 8 September is available here (pdf file, 113kb).

Cool!

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Website of the Samuel Oschin Telescope with which the new planet was found.

I thought they already discovered a 10th planet??? Sedna??

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I thought they already discovered a 10th planet??? Sedna??

I believe Sedna is classed as a planetoid, see this article.

I think the debate about planetary status is still ongoing and will probably change several times in the future.

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Sometimes I think we are alone in the universe, and sometimes I think we are not. In either case the idea is quite staggering.

I thought they already discovered a 10th planet??? Sedna??

I believe Sedna is classed as a planetoid, see this article.

I think the debate about planetary status is still ongoing and will probably change several times in the future.

yeh... I'll read that article.... when It opens, but I know what you mean. There's debate about whether Pluto is actually a planet as well.

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More info from the new discovered planet, from the discoverer himself.

Interstellar interloper or 10th planet?
Prentice says an object must technically travel around the Sun on a flat plane and have a circular orbit to be considered a planet.

2003 UB313, which is rumoured to soon be named Xena, orbits at a 45° angle to the rest of the solar system.
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Either we have a 10th planet or we have only eight planets.
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Read the article here.

Either we have a 10th planet or we have only eight planets.

Possibly downgrading Pluto from planetary status?

Farewell Pluto?

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Join TeamACC

Sometimes I think we are alone in the universe, and sometimes I think we are not. In either case the idea is quite staggering.

Interstellar interloper or 10th planet?
Prentice says an object must technically travel around the Sun on a flat plane and have a circular orbit to be considered a planet.

2003 UB313, which is rumoured to soon be named Xena, orbits at a 45° angle to the rest of the solar system.
............

Either we have a 10th planet or we have only eight planets.
.............

Read the article here.

To me, the possibility of a large interstellar object captured by the Sun is much more exciting than just another home grown planet. But, if it does come from outside the solar system, then doesn't that mean it is not a Kuiper Belt object? In this article, "Parker says the only way to prove its planetary credentials is to obtain samples to see "if it's made out of the same stuff as the rest of the solar system".", but in the previous article you posted ("from the discovered himself") they claimed that the surface of the new object "looks remarkably similar to Pluto" chemically, based on reflected light. That would seem to deny the possibility that it "isn't made out of the same stuff", unless the surface has just been coated with local stuff over time.

Also, to suggest that the new object does not travel around the Sun in a flat plane is misleading. Of course it travels in a flat plane! That plane is just tilted at a 45 degree angle to the flat plane that we orbit in.

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