IAU Rules Pluto Still a Planet

scottyscout writes "NPR reports that Pluto has dodged a bullet. An international panel has unanimously recommended that Pluto retain its title as a planet, and it may be joined by other undersized objects that revolve around the sun. Some astronomers had lobbied for reclassifying Pluto as its so tiny. And at least one major museum has excluded Pluto from its planetary display. But sources tell NPR that under the proposal, to be presented at a big meeting of astronomers in Prague next week for a vote, Pluto would become part of a new class of small planets and several more objects could be granted membership."

I "relate to its inadequacy"

[ExE122]

According to wikipedia [wikipedia.org]:

-Earth's Diameter: 12,756.274 km
-Pluto's Diameter: 2306±20 km
-Jupiter's Diameter: 142,984 km
-Proportion of Earth to Pluter: 12756.274 / 2306 = 5.531
-Proportion of Jupiter to Earth: 142984 / 12756.274 = 11.209

Hmm... Jupiter has over twice the proportional difference with Earth as Earth has with Pluto. So I guess Jupiter wouldn't really consider Earth a real planet.

Personally, I think we should leave the little guy alone. Throw UB313 [wikipedia.org] in there as well. Just give it a cool name that fits in with that whole "my very educated mother..." thing.

Like the well learned and professional scientist said: "We'll call them dwarf planets or something".

--
"A man is asked if he is wise or not. He replies that he is otherwise" ~Mao Zedong

Re:I "relate to its inadequacy"

[thePig]

If it is only the size tht was an issue, then yes, your point makes excellent sense.
But, shouldnt we also consider the fact that there is a high probability that pluto was not created from the accretion disk around the sun, from which other planets were formed ?
Especially the plane in which pluto revolves, which is very very different from other planetary planes, should also be taken into consideration, I guess.

A planet should not be just an object which revolves around a star. Rather it is something which should have formed when the star was formed. This we can very easily judge (provided we know) from the heavy metal content and the ratio, I guess.

But, I guess these should have been easily the first points in IAUs discussions. Otherwise, I am completely wrong in my assumptions :-)

Re:I "relate to its inadequacy"

[Cornflake917]

I "relate to its inadequacy"

The article also talked about how children would benefit from Pluto's planethood because it's a "misfit". Shouldn't we be classifying planets based on it's characteristics, not how it affects our culture or how people relate to it? If we classify things based on how people relate to them, we might as well call whales the "misfits of fish." It might be a totally incorrect classification, but at least obiese people have something to relate to now!

Re:If they have such power,,,

[MBGMorden]

Why not just call them planets? People keep throwing up the excuse that "if we call Pluto a planet then there's lots of things that would be planets.". So? Why should we readjust our definition just to keep numbers low? They don't care about some elite social status. If there's 9 in this system or 853, we should call them planets. If we want to nitpick on composition, then Earth and Jupiter certainly aren't the same type of thing either.

Absolute rubbish!

[jrothwell97]

Pluto isn't even anything special in the Kuiper Belt. There are plenty of objects, many of them probably larger than Pluto, that are classed as KBOs, so why isn't Pluto classed as such? If they found an Earth-sized rock orbiting a thousand AUs from the Sun, THAT should be classed as a planet.

Re:I "relate to its inadequacy"

[mrchaotica]

But, shouldnt we also consider the fact that there is a high probability that pluto was not created from the accretion disk around the sun, from which other planets were formed ?

Couldn't it be argued that the accretion disk includes the Kuiper Belt?

Re:I don't get it

[StupendousMan]

Astronomers were debating Pluto's status back in the early 90's.

No, the overwhelming majority of astronomers were not. We don't care. Really. The issue "what is a planet?" has for most of us the same urgency and relevance that "what is a continent?" has for geologists.

No, the scientific community is in a constant state of polarization, between the old guard, wary of new things and ideas, and the new breed, mainly young researchers thinking outside the box.

There certainly _are_ topics on which there is vigorous debate in the astronomical community -- for example, the nature of gamma-ray bursts, or the accuracy and precision of the cosmological distance scale, or the physics of supernova explosions. But this isn't one of them. The issue exists solely because a very few people who (for some reason) are seeking publicity go to the media periodically with a "new twist" on this question.

Adding the question "is Pluto a planet" to the list of serious astronomical questions of the day does a disservice to those other questions.

Historical importance...

[posterlogo]

Pluto really has more of a historical importance than anything else. We do have good definitions of what a planet is (condensed remnants from star formation's accretion disk), and it should be pretty easy to prove that Pluto does not fit the bill. Size is not the important thing -- Mercury isn't huge, but it certainly is a planet. I guess NASA's New Horizons mission should help clear this up in a decade or so, but I don't think that will have to result in changing the status of Pluto -- leave it alone as a planet (even though it isn't), purely for historical reasons. The search for an object to help explain discrepencies in Neptune's orbit formed a major part of Pervical Lowell's [wikipedia.org] life, and he made significant contributions to astronomy. I think the IAU astronomers may want to leave Pluto a planet as an honor to those who discovered it at a time when such discoveries were very difficult. More and more KBO's will be discovered, but will inevitably be farther and farther away. So -- 9 planets it is, even though it's really 8.

The problem is not with just Pluto

[ChrisA90278]

People seem to be mising the point. The problem here is not to vote on if Puto is a planet or not. The problem is to define what is a planet. Many people have proposed ways to define "Planet" but then what you apply the proposed definition to our solar system yu get undesired results. Almost every resonable proposed definition results in a solar system with either 8 planets or more than 9. Next problemis that you want your new definition to "work" outside the our solar system on the 100+ planets that have been discovered around other stars.