Pluto Could Lose Planet Status

PhysOrg.com ^ | 21 June 2006 | Staff

[PatrickHenry]

At its conference this August, the International Astronomical Union (IAU) will make a decision that could see Pluto lose its status as a planet.

For the first time, the organisation will be officially defining the word "planet", and it is causing much debate in the world of astronomy.

There is only one thing that everyone seems to agree on: there are no longer nine planets in the Solar System.

The debate has been brought to a head by the discovery of a potential 10th planet, temporarily named 2003 UB313 in January 2005. This new candidate planet is bigger than Pluto.

The question now facing the IAU is whether to make this new discovery a planet.

Pluto is an unusual planet as it is made predominantly of ice and is smaller even than the Earth's Moon.

There is a group of astronomers that are arguing for an eight-planet SolarSystem, with neither Pluto or 2003 UB313 making the grade as a planet; but a number of astronomers are arguing for a more specific definition of a planet.

One of these; Kuiper Belt researcher Dr Marc Buie, of the Lowell Observatory in Arizona, has come up with a clear planetary definition he would like to see the IAU adopt.

I believe the definition of planet should be as simple as possible, so I've come up with two criteria," he said.

"One is that it can't be big enough to burn its own matter - that's what a star does. On the small end, I think the boundary between a planet and not a planet should be, is the gravity of the object stronger than the strength of the material of the object? That's a fancy way of saying is it round?"

This definition could lead to our Solar System having as many as 20 planets, including Pluto, 2003 UB313, and many objects that were previously classified as moons or asteroids.

One possible resolution to the debate is for new categories of planet to be introduced. Mercury, Venus, the Earth and Mars would be "rocky planets". The gas-giants Jupiter, Saturn, Uranus and Neptune would be a second category.

Whatever the outcome of this debate there is only one thing that we can be certain of; by September 2006 there will no longer be just nine planets in our Solar System.

[<1/1,000,000th%]

I don't think they did.

But they're revising the whole thing in a 2006 episode anyway.

[Tanniker Smith]

I still say that there's something to the fact that the combined radii of the two members of the Earth-Moon pairing is exactly 7! (7 factorial) miles, which oddly enough is the same as 10!/6!

Numerology and astrology can't BOTH be wrong, can they?

[Surtur]

Nick Fury, Agent of S.H.I.E.L.D.!

[steve-b]

does the body in question have sufficient gravity to maintain the stable orbit(s) of natural satellite(s) of its own?

That depends on how far from the sun it is, which isn't really a good criterion.

[steve-b]

(And this is coming from a guy who had a problem with rationalizing the term "satellite nations" when I first learned about the Soviet Union in 6th grade.)

After Sputnik was launched, there was a joke about Czechoslovakia launching its own satellite... which would circle around Sputnik.

[Skywarner]

But, how would you rate Helen Thomas?

[skinkinthegrass]

Thanks, PH. :D
What's Pluto (the dog) gotta do?

[skinkinthegrass]

Well Pluto's tilted eccentric orbit is more like a comet's orbit than a planet's orbit and most likely it was originally one of Neptune's moons that somehow got free of Neptune's gravity.

Hmmm...an excellent example of the ongoing ancient game of space pool.... :D

[Dazedcat]

I'll bet the citizens of Pluto are plenty angry. I sure would be if Earth lost its' status!

I fear though that this may be the democrats new voter base, disillusioned Plutonians who consider planetary status their right and entitlement.

Shove Pelosi onto a rocketship and let her do some advanced study on this.

[Tanniker Smith]

Pluto in the corner black hole.

Dang, that must be one hell of a cue stick.

[Xenalyte]

Yeah! What's with this UB313 crap? I thought the planet was gonna be named after me!

[skinkinthegrass]

But, how would you rate Helen Thomas?

NOW YOU"VE DONE IT!
....someone's gonna post her picture (but I won't :) now.

[Xenalyte]

You just HAD to bring Hasselhoff into it, didn't you? ;)

[skinkinthegrass]

Dang, that must be one hell of a cue stick.

Yes....It Is (its' at least 19.18 au long :), of course, the size of the pool table (the Ort Cloud :) is important , too.

[Waverunner]

My Fury knows no bounds.

[clyde asbury]

Thanks for the comments, Sergio.  His Out of the Darkness: The Planet Pluto earned my great respect for him, when I was a young teen.

[drlevy88]

What the bleep does this have to do with EVOLUTION.

[longshadow]

The Seventh Planet is tickled by this news....

[PatrickHenry]

The Seventh Planet is tickled by this news....

Someone tickled Ur_____?

[Doctor Stochastic]

If the point about which two bodies orbit each other is not beneath the surface of one of them, but is between them, then I'd call that a binary system.

Sometimes the Sun-Jupiter system has its center-of-gravity outside the Sun's surface.