Part 1, Sat, 26 Aug 2006 15:21:14. Words from Brother Guy Consolmagno, recieved via mailing-list e-mail and re-posted here with his permission. ("Other convention" refers to the fact that the World Science Fiction Convention was happening at the same time.)
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What follows is adapted from a column I wrote for a British weekly, and e-mails sent to the American Astronomical Society, Division for Planetary Sciences board (of which I am a member)...

Never mind the 4,000 astronomers attending dozens of seminars and joint discussions about stars and galaxies in Prague (did you know that new evidence for dark energy has been found?); the news at the triennial General Assembly of the International Astronomical Union (IAU) is the changing status of Pluto.

General Assemblies are different from typical scientific congresses. Rather than being focused exclusively on presenting scientific results, the main point is to decide on all the arbitrary but necessary definitions that let us talk to each other and understand each other's data. For example, were worrying about tweaking the definition of latitude and longitude on the Moon to match the the expected precision of the coming generation of lunar spacecraft from India, China, Japan, and the US.

Likewise, defining what is a planet is both arbitrary and necessary. How do we name the newly discovered objects out beyond Pluto, that rival Pluto in size? (The rules, and the committees, for planets are different than those for comets and asteroids.) Which committee keeps track of their orbits, and assigns names to their surface features? What definition works for planets around other stars?

I sat on earlier planet-defining committees, but always at the last moment our agreements fell apart. The following is the proposal by the most recent committee (this time much smaller, and including historians and journalists as well as scientists and a meeting of IAU's Division III (the planetary scientists' corner of the IAU), a general consensus formed around a slight modification of the original proposal.

To be a planet, an object would have to be smaller than a star, in orbit around a star, but large enough to pull itself into a rounded shape. One then divides the planets in our solar system into the eight largest planets, whose gravity dominates their regions of space; a new class of less dominant, Pluto-like "dwarf planets"; and all the small bits of flotsam and jetsam like comets and asteroids.

More controversial aspects reported in the news coming from the original definition, worrying about double planets and the like, were dropped in the final definition. And all the really tough issues, deciding which committees handle dwarf planets, including naming the new candidates in the outer solar system, will be left to us in Division III.

The process was interesting in its own right. The proposal from the seven-person committee was presented the first week of the meeting, on a Wednesday, published in the meeting newspaper. It merely defined a planet on the basis of gravity overcoming body forces to produce a shape approaching hydrostatic equilibrium. By that, Pluto and Ceres and the new big guys would all be planets. On Friday of that week, during a session of the business meeting of Division III, an open discussion was held where the dynamics people presented an alternative definition that also included as a necessary part of the definition the idea that a planet had to gravitationally dominate its region of space, causing noticeable perturbations on the star and the other big planets, and have "cleared out" its region of the solar system when it was formed.

The resolutions committee of the IAU took these ideas and tried to simplify them so that the general public would get the idea, then published the new version in the conference paper on the following Tuesday. That Tuesday at noon was an hour-long session hosted by the President of the IAU, open to everyone, that was very acrimonious, as the dynamics people felt their ideas were over-simplified. Others had a hard idea understanding those ideas.

That evening, a second session was held, hosted by a member of the resolutions committee who is probably the most famous and well-respected astronomer in the world: Jocelyn Bell-Burnett (who is more famous for not getting the Nobel Prize than most Prize winners are!). She did a masterful job of listening and explaining, and then the new versions of the proposal were prepared for the final General Assembly on Thursday afternoon.

The resolutions were divided into four parts. Resolution 5a is essentially what passed. There was then a vote on 5b, adding the word "classical" to describe the big eight planets. As Dr. Bell-Burnett very cleverly illustrated, the intent of this was to maintain that both Pluto-sized bodies and the big 8 are planets, just different kinds of planets.

The vote on 5a, defining three classes of bodies (planets, dwarf planets, small solar system bodies) passed overwhelmingly.

5b, which would have named planets as "classical planets" and thus included "dwarf planets" as a kind of planet, failed narrowly (by about 50 votes).

Then came two resolutions, to confirm Pluto's "specialness."

6a, noting that Pluto is the first discovered of a new population of bodies in the Transneptunian region, passed handily.

6b, naming this population "plutonian objects" failed by less than ten votes.

To me, the final definition makes scientific sense: my own research shows a distinct difference between small but compact objects like Pluto and the loose rubble piles of asteroids. And one advantage of this definition is its creative ambiguity. In reply to the question, Is Pluto a planet? it will be equally true to say, yes, it's a dwarf planet and no, it's a dwarf planet. That reflects the ambiguity of nature itself.

--Brother "outgoing IAU Commission 16 president..." Guido

(Continued on next rock.)

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"For shame, gentlemen, pack your evidence a little better against another time."
-- John Dryden, "The Vindication of The Duke of Guise" 1684

Part 2, Sat, 26 Aug 2006 15:24:22.
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And the follow-up, based on more e-mails to the DPS committee...

Following this vote and all the press attention (it's August, and the Silly Season) a bunch of planetary scientists in the US who didn't like the fact that their pet resolution failed, have started circulating a "petition" asking that the matter be "reopened." The DPS was asked to take a stand on this... and I commented:

The petition is an expression of unrest, but practically, think about it; what possible change can it effect? The only people who can take any action at all are the executive committee of the IAU, but remember, the result that came out of the IAU was NOT what the executive committee wanted -- thus for them to do anything at all but to quietly accept the vote would be seen, legitimately, as a violation of the IAU's own rules and as the executive committee dictatorially imposing its will, even if it were only to say that the issue was going to be revisited. Believe me, you had to be there to understand the passions on this issue among IAU members... and to be impressed with how well they did, given those passions.

I am reminded of my friends who [female dog] and moan about US politics but in fact are not registered voters. The fact is, dynamicists are more active in the IAU, and their presence won the day. On the other hand, at my Commission 16 meeting at this IAU the entire turnout of scientists who study planets and moons was FIVE PEOPLE. Out of a commission membership of over 200.

The disgrace is not in the IAU, but in the planetary sciences community who for more than a decade now have been studiously ignoring the IAU, refusing to spend the time working on its committees, often even refusing to come to give review talks about matters of interest to the wider astronomical community, too often refusing to attending the GAs (or parachuting in just for the one session they are interested in, without sticking around for the commission meetings and the opening and closing General Assemblies where these matters are voted upon), on the excuse that "I can't be bothered, I'm too busy." Fine. If you can't be bothered to do the scut work year in and year out to make the IAU and its commissions work (and believe me, it's time consuming work of the sort that is noticed only when it isn't done!), then you have no right to let yourself be bothered by what results you end up with when a vote at the IAU doesn't go your way. And you certainly have no right to critique a process that you weren't there to see.

The IAU is important for a number of reasons, not the least of which is that there is a real sense outside the US that the US dominates astronomy, and the IAU goes out of its way to balance this issue. For the Division for Planetary Science of the American Astronomical Society to do anything other than endorse the IAU will be seen as the US attempting to force its will on the world. Yet again.

I will note in passing, having sat on the original (stalemated) 19-member committee to make this definition, I have heard every possible definition; and I have heard every possible rebuttal to every possible definition. You can easily get a majority to agree that "something better" is possible, but you'll never get a majority to agree on what that "something better" is!

Though the IAU didn't end up exactly where I would have liked, either, I can live with what passed and in fact it's much closer to what I would want than I ever expected to get. I am satisfied that the procedure was as fair as the IAU could have made it, and that the final definition is one that will adequately allow the IAU's Division III to get on with its work.

And that, after all, is what was the vote was all about. It's an IAU document for IAU's purposes. The IAU knows (as it said explicitly at the GA) that it can't control the definition of words in all the world's languages, or how the general public uses those words. It can only define terms so as to determine how it goes about distributing its work load to appropriate committees and working groups.

Finally, a point that I think we scientists forget is that a definition is not a computer program. One can (and must) depend on common sense and good will to prevail over inadequate syntax.

Brother "... and incoming DPS chairperson" Guido

__________________
"For shame, gentlemen, pack your evidence a little better against another time."
-- John Dryden, "The Vindication of The Duke of Guise" 1684

And finally, Mon, 4 Sep 2006 19:25:45.
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About the vote in the General Assembly:

As we entered into the hall, those with "member" badges were given yellow cards that we were to raise when a vote was taken.

The "planet" voting was handled this way. All the resolutions had been distributed beforehand so everyone had a clear idea of what was coming up, and what each vote meant.

Resolution 5a: this one split objects in the solar system into three classes, planets, dwarf planets, and small solar-system objects. It was discussed and then taken to a vote, people raising their yellow cards. As the vote was overwhelmingly in favor, no vote count was taken.

Resolution 5b: this added the word "classical" to the first category of planets. It was made clear that the intent of this change would be to include both the large eight bodies and the dwarf bodies together under the umbrella term "planet." There was a vote in favor which was counted, as I recall, and I think it got more than 200 votes in favor; but then when the nays were counted, it was clear that the nays overwhelmed the yeas and so no count was needed.

Resolution 6a noted that Pluto was the first of a special class of trans-neptunian dwarf planets. This passed on a counted vote, 237 in favor, 157 against. (394 total votes).

Resolution 6b explicitly named these bodies, "plutinoids" (I think). It failed, 183 votes in favor, 186 against (369 total votes.)

The vote count on 6a is what is being used as a way of saying that "only 400 people voted" but my recollection of the voting on resolutions 5a and b is that there were many more votes cast in those cases. As the votes got more contentious, more people abstained (note the vote totals for the two versions that were counted.) My recollection, of course, could be wrong.

__________________
"For shame, gentlemen, pack your evidence a little better against another time."
-- John Dryden, "The Vindication of The Duke of Guise" 1684

I thought it was interesting that they should raise the issue of non-voters as something bad, but in the second section raise the issue of possible non-voters.

I know, I know.

I thought this would come up.

The US does dominate astronomy, for the simple reason that it spends more money on it. This is especially true in planetary astronomy, where US astronomers have a great advantage as they get preferential access to the results of all NASA planetary probes. But you can see why non-Americans can find this, shall we say, disconcerting.