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NASA Scientists Propose New Definition of Planets, and Pluto Could Soon Be Back (sciencealert.com)
Rei writes: After several years of publicly complaining about the "bullshit" decision at the IAU redefining what comprises a planet, New Horizons program head Alan Stern and fellow planetary geologists have put forth a new definition which they seek to make official, basing planethood on hydrostatic equilibrium. Under this definition, in addition to Ceres, Pluto and other Kuiper Belt objects, large moons like Titan and Europa, as well as our own moon, would also become planets; "planet" would be a physical term, while "moon" would be an orbital term, and hence one can have a planetary moon, as well as planets that orbit other stars or no star at all (both prohibited under the current definition). The paper points out that planetary geologists already refer to such bodies as planets, citing examples such as a paper about Titan: "A planet-wide detached haze layer occurs between 300-350 km above the surface; the visible limb of the planet, where the vertical haze optical depth is 0.1, is about 220 km above the surface."
That's just the issue: that's not what happened. The IAU discussion was a disaster. Here's the timeline:
2005: The IAU appoints a committee to investigate the issue and generate a proposal. The committee investigated the issue for a year.
The IAU meeting is scheduled from 14-25 August 2006.
16 August: The committee recommends a definition based on hydrostatic equilibrium. No "cleared the neighborhood" nonsense. They publish their draft proposal.
18 August: The IAU division of planetary sciences (aka, the people who actually deal with planets) endorses the proposal.
Also 18 August: A subgroup of the IAU formed which opposed the proposal. An astronomer in the group (aka, someone who studies stars, not planets) - Julio Ángel Fernández - made up his own "cleared the neighborhood" definition. While most of the membership starts to trickle away over the next week, they remain determined to change the definition.
22 August: The original, hydrostatic equilibrium draft continued to be the basis for discussion. There were some tweaks made (some name changes and adjusting the double-planet definition), but it remained largely the same.
Late on 22 August: Fernández's group manages to get to just over half of the attendance at the (open) drafting meeting, leading to a very "heated" debate between the two sides.
22 to 24 August: The drafting group begins to meet and negotiate in secret. The last that the general attendance of the conference knew, they'll either end up with a vote on a purely hydrostatic definition, or (more likely) no vote at all due to the chaos. Attendence continues to dwindle, particularly among those who are okay with either a hydrostatic definition or none at all.
24 August: The current "cleared the neighborhood" definition is suddenly proposed and voted on on the same day. Only 10% of the conference attendance (4-5% of the IAU membership) is still present, mainly those who had been hanging on trying to get their definition through. They pass the new definition.
It's not generally laypeople who are upset about how it went down, it's IAU members. Many have complained bitterly about it to the press. The IAU's own committee of experts was ignored, in favour of a definition written in secret meetings and voted on by a small, very much nonrandom fraction of people, the vast majority of whom do not study planets.
If there's one thing I hate, it's people who pretend that anyone who opposes the IAU definition does so because they're ignorant morons overcome by some emotional attachment to Pluto, when in reality it's been planetary scientists themselves who have been the definition's harshest critics, because it's an internally self-inconsistent, linguistically flawed, false-premise-based definition that leads to all sorts of absurd results and contradicts terminology that was already in widespread use in the scientific literature.
I'll never forget the last thing grandma said to me before she died: "What are you doing in here with that knife?!?"
...for "downgrading" Pluto. He went on to write a snarky book, the title of which -- "How I Killed Pluto and Why It Had It Coming" -- tells you all you need to know about this self-absorbed douche.