Pluto Making a Comeback

anthemaniac writes "Space.com reports that the American Astronomical Unions Division of Planetary Scientists recognizes the IAU's authority to make a new planet defintion but expects it to be altered. Separately, 300 astronomers have signed a petition saying they won't use the definition. All this stems from the discontent over how only 424 astronomers voted on the proposal that demoted Pluto. Looks like this little dog is on the comeback trail."

you can say this ...

[Anonymous Coward]

What more can you say?

Pluto is smaller than another "non-planet", Pluto has an eccentric orbit, ... actually there is no more you can say other to repeat the irrefutable arguments for it not being a planet. IT AIN'T A FRICKEN PLANET get over it.

Re:Pluto in School

[lbrandy]

Nope, that's Venus and Earth. Mars is about one-third the mass of earth, IIRC.

Quoth the wikipedia, "Mars has half the radius of the Earth and only one-tenth the mass, being less dense, but its surface area is only slightly less than the total area of Earth's dry land".

Re:Fuck the pissy "scientists"

[4D6963]

They just called it a planet because they lacked the information we have.

Actually they called it a planet because they were looking for one. Unfortunatly for them, it wasn't the giant Planet X they were expecting from their calculations.

Metric!

[wall0159]

That's approximately 117 mm for the real scientists ;-)

Re:Can't seem to find Pluto at all

[Bob Cat - NYMPHS]

Wrong domain. The www means you're requesting Pluto from the Earth.

Re:waiting

[cptgrudge]

Your post intrigued me, and after some quick research with the help of Google, I agree. You can fire up Celestia and actually see some of them, just make asteroid orbits and names visible. Pluto fits right in with them; it seems to be the largest of them.

For you unbelievers, here's a list. These objects are all out of the "normal" plane of orbits, just like Pluto.

Name, Radius
Pluto, 1,151km
Ixion, 600km
Quaoar, 625km
Orcus, 800km
Varuna, 450km

And these are just some "nicely named" ones. See "2003 EL61", "2005 FY9", etc for more examples. And you can add more [celestiamotherlode.net] as well. For those with computers that aren't slow, this page [cornell.edu] contains a Celestia ssc of 1007(!) TNOs. Doughnut shaped indeed.

Also, there is a class (like 20%-30%) of them called Plutinos [cornell.edu] which share Pluto's stable 3:2 orbital resonance with Neptune. How did this come to be? There are theories [hawaii.edu], but nothing definitive yet.

The debate will continue, but if you look at that Celestia ssc of 1007 TNOs, it is pretty clear that Pluto is not a "major planet". If it is, then we've got dozens, possibly hundreds of them.

(Apologies if this has been covered before.)

Re:FP?

[comrade k]

Not to mention the fact that neutrons are subatomic particles.

Do you work for Lockheed Martin?

[rolfwind]

http://www.cnn.com/TECH/space/9909/30/mars.metric. 02/ [cnn.com]

7 inch would be about 177.8mm.

Re:How is it important?

[rucs_hack]

planet used to mean 'anything that moved in the night sky', the literal translation being 'wandering star'.

Originally even the Sun was classed as a planet, as was the moon, any comets that were seen, jupiter, the lot.

As a definition it's changed a lot.

Re:there's only one reason for all this

[Anonymous Coward]

I think you mean Lowell [wikipedia.org].

Re:waiting

[SEE]

Dank and dismal. From the river Styx, which Charon ferries people across to the realm of Hades (Pluto to the Romans), a dank and diamal realm of the dead very similar to the Jewish Sheol, both of which are often conflated with Hell in Christian cosmology . . .

Re:FP?

[mcvos]

Can't say I disagree with keeping the old definition, when they had to change the definition of a planet to exclude Pluto.

Remember that all of this has happened before. Once upon a time, Ceres was a planet. Then other asteroids were discovered. The first few became planets too. Then astronomers realised that these were all objects from a seperate class, and redefined them not to be planets. Pluto is exactly the same. We thought it was a planet when it was the only KBO we knew. Now we know there's millions more of them, and Pluto isn't even the biggest of them. Pluto is member of a seperate class of objects, and will be defined as such. If not now, than after a few more big KBOs have been discovered.

Re:Consistent terminology is crucial to any field

[Twiek]

You do realize that Ceres was classified as a planet before the discovery of more asteroids, right?

What makes the Kuiper belt so different that its inhabitants get to be planets, and the asteroids don't?

Your problem here

[Anonymous Coward]

is that you seem to think that there is a *re* definition of "planet" going on here. That isn't the case. This is about the definition of planet. There has been NO definition of what "planet" means and they are trying to work out what defninition to use.

Deciding a version that includes pluto is as abitrary as deciding on one that excludes it. However, excluding Pluto-accepting-definition means that we have a reasonable chance of remembering what planets we do have. A definition that includes pluto would either have to have "and pluto, because we thought it was at the time" at the end. Which reads a little silly.

So, to reduce the sillyness, the actual definition (which is not changed, it is brand new and never defined, except as a list of names (which isn't a definition: no extrasolar planets are named in the list, so they can't be planets...), a definition is made that just happens to exclude pluto as a planet.

Re:Consistent terminology is crucial to any field

[pnewhook]

Pluto should have never been classified as a planet, and was only done so for political reasons, not scientific. It's not in a standard orbit like a planet, it highly eccentric, crossing Neptune's orbit as well as being tilted significantly in the plane of the solar system as compared to the other planets. It's moon is over half its own diameter.

It's probably a rock/ice blob from the Oort cloud that came too close to one of the gas giants and ended up in a roughly stable orbit. It's more like a failed comet than a planet.

Re:waiting

[wrightam]

Actually, Orion IS a constellation in its own right. But you are correct. The "Big Dipper" is an asterism, just an easily recognizable part of Ursa Major.

Re:waiting

[frankie]

Your Celestia is at least a year out of date, because Pluto is at best the SECOND largest TNO/KBO, and probably lower than that. Here's a good illustration: http://en.wikipedia.org/wiki/Image:2006-16-d-print .jpg [wikipedia.org]

p.s. I'd like to remind everyone that Ceres, Pallas, Juno and Vesta all used to be officially recognized planets ... until it was discovered that there are thousands of other objects much like them in the same part of space. Then they got redefined. Hmm... does this pattern of events sound familiar?

Re:waiting

[jc42]

[M]uch of the argument to keep Pluto as a planet hinges around nostalgia, and "keeping the textbooks the same." How is that science? Things change; science marches on.

Actually, there is some scientific precedent for this. For example, a few years back zoologists figured out that Apatosaurus and Brontosaurus were the same species. Apatosaurus was the older term, so it was decreed the official name. There was a minor outcry, because the Brontosaurus was the favorite dinosaur of so many people. So the decision was made to accept Brontosaurus as a synonym of Apatosaurus.

This definition was basically a bit of silly PR. But it did have one technical effect: It meant that Brontosaurus couldn't be re-used to name a new dinosaur species. This is reasonable, since so many older texts use the term. And it was good from a scientific field that can be rather abstruse at times.

Astronomers have pointed out that "planet" has never really been a technical term. So it definition doesn't mean much to them. They'll continue to talk about "objects" and "bodies", and give specs to more precisely say what sort of thing they're talking about.