"Pluto is dead" - Mike Brown, It's official Options

[SigurRosFan]

- BREAKING NEWS: Pluto Demoted, No Longer a Planet

- Pluto loses status as a planet

[gpurcell]

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.

[mchan]

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.

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.

[karolp]

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.

[gpurcell]

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.

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.

[dvandorn]

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

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

[karolp]

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

[David]

I consider the (apparent) fact that I am able to discuss this planetary classification issue halfway intelligently to be positive proof that it is not in any sense a scientific question.

[karolp]

I consider the (apparent) fact that I am able to discuss this planetary classification issue halfway intelligently to be positive proof that it is not in any sense a scientific question.

And it won't really be until we find out what a planet REALLY means by exploring other planetary systems and seing what they are like and might be. I particularly find any criteria of circular orbits to be inappropriate and Sol-centered - there are "jupiters" and "neptunes" in eccentric orbits around other stars. But we shall not understand what it really means to "be a planet" until we see more planets around other stars. For now it is just a "distant flavour", not insight. But we ARE intelligent enough to tell a KBO from a planet. And until COROT tells as some more or we discover an "earth" in the Oort Cloud the case appears to be settled.