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Pluto and its biggest moon, Charon  (Source: NASA)
Pluto gets new classification: Plutoid

After being demoted from a planet to a dwarf planet by the International Astronomical Union (IAU) two years ago, the IAU has announced the term "plutoid" will be given to Pluto and similar dwarf planets.  Members of the IAU argued amongst themselves for two years, confused on how to classify dwarf stars like Pluto.  

Only dwarfs orbiting further than Neptune can be classified as a plutoid, and they must also circle the sun and be large enough to have their own gravitational field.  Pluto's permanent classification as a plutoid now means Neptune is the outermost planet in Earth's solar system; one complete orbit around the sun takes almost 165 years.

"Plutoids are celestial bodies in orbit around the sun at a distance greater than that of Neptune that have sufficient mass for their self-gravity to overcome rigid body forces so that they assume a hydrostatic equilibrium (near-spherical) shape, and that have not cleared the neighborhood around their orbit," said the IAU.

Pluto and Eris remain the only plutoids at the moment, but astronomers expect to find other small bodies that meet the qualifications to be a plutoid.

The controversy over Pluto's planet status has been strong for years, and the IAU-created plutoid classification most likely will not end the debate.  In fact, it is unlikely the debate regarding Pluto's status and what it should be classified as will never end, and defining it as a "plutoid" will only add fuel to the fire.

Many astronomers remain angry that Pluto, considered a planet for around 70 years, could have its status demoted so easily by the IAU.  Text book publishers and teachers must now begin to teach students that Pluto lost its planet status and is now a plutoid, along with describing the new classification.

The IAU has been the sole organization responsible for classifying all planetary bodies for more than a decade.

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RE: Pointless
By fishbits on 6/13/2008 9:20:16 AM , Rating: -1
A criterion that was chosen to support a preconceived goal. I suppose now stars in binary systems aren't really stars, since they haven't cleared their systems. I know, we'll call them "binoids!" Hey, since a lot of the low-hanging fruit is gone, we can all play taxonomy wars, looking for niggles to claim that an object isn't really an object.

This was a pointless nerd circle jerk at the *deliberate* cost of some of the public's good will (and hey, space/ astronomy has more public support than it knows what to do with these days, amirite?) A shame they couldn't gather enough grown-ups to say "Pluto's been a planet for many decades. We'll tighten the definition up for future discoveries in and out of our system, but we'll leave Pluto the F alone. It's the right thing to do, even if not the achingly pedantic one."

RE: Pointless
By mcnabney on 6/13/2008 9:40:57 AM , Rating: 5
Here is how it is.

They had to reclassify Pluto and drop down to 8 planets, or prepare to start adding a lot more. Eris is bigger than Pluto, so that would make ten. There are three others which are also round (but smaller than Pluto) which would follow. Unless you want the planet count to start going up towards 20 it was decided that the 'planet' definition would require the object to clear its own orbit. Pluto and the other trans-Neptunians don't.

RE: Pointless
By fishbits on 6/13/08, Rating: -1
RE: Pointless
By Machinegear on 6/13/2008 10:55:54 AM , Rating: 5
Naw... You got it all wrong.

Sure up to recently, 9 was a good number (less than 10 fingers) but today we really had to renormalize the solar system down to 8 planets. Nine planets were already pushing the limits of today's youth. The adults in charge had to think fast to stop the scientists from counting up to 20! Can you imagine the educational disaster??? Kids would have to use toes! Toes I tell you!!!

RE: Pointless
By FITCamaro on 6/13/08, Rating: 0
RE: Pointless
By Seemonkeyscanfly on 6/13/2008 2:46:07 PM , Rating: 1
Well there is no humor when talking about Pluto.
Where you are talking about Pluto the place, Pluto the dog or not Plutoid the newly developed cult for planet want to be planets, or hunks of mass, or or or fine Plutoids......

RE: Pointless
By Seemonkeyscanfly on 6/13/2008 2:54:08 PM , Rating: 2
typooo my bad... Should be whether not where.

RE: Pointless
By bodar on 6/13/2008 8:28:37 PM , Rating: 2
Pluto is serious bidness, especially on the internets.

And double-especially for Pluto the dog, since he's the only only mentally challenged character in the core Disney universe. Ducks, mice, and even other dogs talk, have jobs, go on vacations, and lead enriched, anthropomorphic lives, but not Pluto. He's just a dog. OK, that was way longer than intended. /rant

RE: Pointless
By Pythias on 6/19/2008 1:02:31 AM , Rating: 2
Kids would have to use toes! Toes I tell you!!!

I can count to 21 when I'm not wearing now.

RE: Pointless
By Seemonkeyscanfly on 6/13/2008 11:19:14 AM , Rating: 2
Great so after 6 billion years Pluto finally has a nick name. :)

Though I agree one should keep things simple when possible. However, what you are talking about sounds like far left wing politics – (Tell the people what they want to hear, keep them from the truth. The truth will just confuse them and make them unhappy). I mean so what if we have 8 or 38 planets. If in the future we find more then we add more planets to the list. Either with more or less planets, I'm not going to be able to visit any more then just one of them and see maybe 4 or 5 of them from my telescope in the backyard.
So can you explain the harm in having 20 planets? (other then just more to learn)

RE: Pointless
By masher2 on 6/13/2008 11:35:05 AM , Rating: 1
> "I'm not going to be able to...see maybe 4 or 5 of them from my telescope in the backyard."

Err, you can see five planets just with the naked eye alone...six, if you have good eyes.

RE: Pointless
By Seemonkeyscanfly on 6/13/2008 11:43:28 AM , Rating: 2
I live near a large city....the lights kill the night viewing of the sky....
Point being if there are 8 planets or 20 planets it's not going to change our lifes. So, why try to keep the number of planet at 8 or 9?

RE: Pointless
By PrinceGaz on 6/13/2008 3:22:11 PM , Rating: 5
Actually you can see six planets with the naked eye alone... seven, if you have good eyes. You seemed to forget that one of them is seen by looking down rather than up :)

RE: Pointless
By murphyslabrat on 6/14/2008 9:24:33 PM , Rating: 2
Gentlemen (and ladies, I realize some of you exist on this forum), this man needs a six.

RE: Pointless
By MRwizard on 6/15/2008 6:09:58 PM , Rating: 2

RE: Pointless
By masher2 on 6/13/2008 11:19:46 AM , Rating: 5
> "This was a pointless nerd circle jerk at the *deliberate* cost of some of the public's good will..."

It's a scientist's job to perform science, not to seek goodwill. Decisions on taxonomy should be influened by rational thought, and not public opinion.

By the way, the public is still free to continue calling Pluto a planet if they wish. They're wrong about so many other things in science, I doubt one more error will make much of a difference.

RE: Pointless
By Mojo the Monkey on 6/13/2008 3:42:47 PM , Rating: 1
Science just needs a new publicist. :)

Also, come on. That quoted comment is just hilarious to read, whether you agree or not.

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