He even said that there is every chance we will find something the size of Mars or even Earth..but we'll have to call it a dwarf planet.

That's just astonishingly short sighted.

Doug

See, that to me, sums up why I really dislike this definition. Personally, I don't think it is THAT big of deal whether or not Pluto remains a planet, but in the attempt to remove Pluto, they have shut the door for all intents and purposes on the possibility of finding planets in the cold deep. And we aren't just talking about problems for Mars and Earth-sized objects, even larger objects far out would have problems clearing their neighborhoods as go farther out.

I to don't really care if Pluto is or isn't a planet...but I DO care when the definition they've come up with is so flawed and counterintuitive.

Doug

Now, in the books, NH will be seen as a new class of explorer
We have had :
Spoutnik 1 to the Earth
Luna 1 to the moon
Mariner 2 the first to a planet
Pionner 10 the first to (outside planets and) outside the solar system (may be Voyager 1's better pick)
Giotto to a comet
...you can complete the very limited list of "new explorers"
In that sense, its very name "New Horizon" couldn't have been a better choice. I personaly don't mind whether Pluto is or isn't a planet, I want to understand our solar system and how it compares to others. Go NH, Go, tell us what's up there.

Yup, that's been my other big problem (after the whole neigbourhood clearing issue) with all this.

Dwarf Planet: Not necessarily a dwarf and definitely not a planet. Talk about confusing. Worst name ever!

My wife tolerates my space exploration obsession, teasing me about going to JPL websites and the like. She's your basic, educated person for who space is at most a passing thought.

This Pluto thing got her pissed off enough to rant about it. Which is surprising.

Her beefs:
1) What the heck is the "IAU" and who gave them the authority to determine something like this?
2) Historical precedence ought to count for something.

Getting her riled up is an indication of how foolish this decision was.

Now, I'm not an astronomer. But I am a political type, and from my professional perspective this issue was handled incredibly poorly.

First, the IAU did not have to create a set of exclusive definitions. Doing so ensured that the Pluto decision would be a hardball choice over which there could be no compromise. That's a bad situation to be in. The original committee suggestion was quite clever in this regards; by keeping Pluto a planet, while including it in a separate category, the path was laid out for the gradual elimination of it. Without a fight. As the planets of the KBO proliferated, the shorthand would have become: "We have eight classical planets and ### "plutons" beyond Neptune of which we know the most about Pluto." In a generation or two, Pluto and the rest of the planets are separated.

Second, the whole rejection of the committee report was a really bad scene. It looks like a cabal of anti-Pluto types threw out a lot of serious work and imposed their policy preferences over the vocal objections of a significant minority. The small group that actually voted on this only adds to the sense that Pluto was convicted in a kangaroo court.

Third, and this bears on my wife's first point: the IAU has nothing but its internal credibility behind its decisions. By engaging in a hack job on this issue, that credibility has been undermined significantly. That lack of credibility is likely to bear noxious fruit in a host of policy choices: "Well, you all can't even decide what a planet is, when any sixth grader can tell you that! So why should this Congress give you more money?"


In summary, it was exceptionally foolish to allow astronomers, untrained in linguistics, semantics, or politics to have free reign in determining the answer to the Pluto question. The IAU obviously realized this with its initial committee selection. It is most unfortunate that the professional anti-Pluto crowd did not take their advice into account in favor of their ill-considered jihad.

I completely agree and even Mike admits on his website that the definition is flawed.

This is a complete PR disaster for astronomy and science as evidenced by the endless cartoons, polls, etc. So now the public will have even less respect for scientists. As a scientist, I dont see much positive here for science or public understanding of science.

gpurcell's wife is typical of public reaction.

The IAU vote should have tabled this for a later date, given all the internal controversary. Doing nothing or trying again to reach broader consensus would have been better than being hijacked at Prague by a narrow band.

I had thought this as well but did not post it in such a clear and succint way. The effects of the original proposal would indeed be spread out and evolve over time. Even the cultrual planet might diverge from the scientific planet, with Pluto being a cultural planet and not a scientific planet.

And how about having "cultural" bacteria versus "scientific" bacteria? Or "cultural" mammals vs. "scientific" mammals? All in all planet was supposed to be a scientific word. It had only become a cultural one because underfunded science cannot provide much details on what a planet really is so culture filled in.

To use the biological analogy 'Planet' is like 'Bug'

Bug can mean all sorts of things in common english - Bacteria, Virii, small insects etc etc.

In common english - Planet can mean Terrestrial, Gas Giant, KBO etc etc etc.

Perhaps there's an argument to be made for not trying to define the word 'Planet' at all.

Doug

The public does not typically have much understanding of such things as the Kuiper Belt. For them that is pure technobabble. They simply know that Pluto was discovered by an American and has the same name as Disney's cute cartoon dog. They tend to run into a weird "overpersonification" of Pluto defending it from "bullies" and demanding it to be treated like "any other". It was already obvious what Pluto is with the discovery of 1992QB1 in 1992 (the first known KBO). And if that was not enough, discovering Xena - a KBO larger than Pluto did it. Mike Brown - Xena's discoverer and Kuiper Belt explorer understands that. The "public", as well as non-planetary, non-KBO astronomers - don't.

What about "river"? "Mountain"? "Canyon"? Those are all vaguely defined.

I hardly think more funding would shed a lot of light onto this. Maybe whopper projects in Earth-based telescopy to search for more far-out objects.

I disagree. Planet was a word for a category of objects long before science came along.

Definitions are, at some level artificial constructs. There is no "scientific" answer to the question "What is a planet?" because the question itself is not one with truth value. Given a set of criteria, science can determine whether an object matches or fails...but the criteria used are, in the end, subjective.

Very true. If we want to go back to the original definition, a planet is any point of light in the sky that "wanders," i.e., that does not move in the same manner as the stars within the celestial firmament. If we go back to that definition, then any solar system object, no matter how small, that is visible from Earth is a planet.

I guess we could debate whether or not an object must be naked-eye visible to qualify...

-the other Doug

I don't think going back to the original idea devised by the Greeks to be a good idea. All in all the word has certainly evolved and gained some scientific meaning. But the meaning is not complete as we do not know many exotic configurations which might occur in other planetary systems. And by underfunding I mean cancelling such missions as the Terrestrial Planet Finder developed by NASA. But luckily ESA has its COROT mission which is also specifically designed to hunt for exoplanets and it is due to be launched in October 2006