[meteorite-list] Pluto Seems Poised to Lose Its Planet Status

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Tue Aug 22 22:30:15 2006
Message-ID: <0a6f01c6c65c$0e6ad0d0$807cd745_at_ATARIENGINE>

Hi,


> Dr. Pasachoff said. "But someone pointed out that
> this definition will hold for all time and that
> it is more important to get it right."

    All time? Is that all way up to the heat death of universe?
Scientists of the future will care no more about our definitions
than we worry about what the scientists of 100 years ago would
think of them.

    100 years ago, Pickering thought the Moon had an atmosphere
and vegetation; Percival Lowell (you know, those canals on Mars...).
A hair over fifty years ago, substantial numbers of astronomical
scientists thought Venus had oceans, rain forests, a decent climate
(although a bit humid) and its clouds were water vapor; most believed
that Mars still had canals; most refused to believe any extraterrestrial
object could or would strike the Earth or any other planet, nor ever
had (except for a few "cranks"); they knew that the craters of the
Moon were all caused by volcanoes, so none of them ever imagined
any other planet would have many if any craters... It's a long list.

    They weren't stupid, just deprived of data we regard as common
now. Are we "moderns" deprived of data? Compared to the future,
we're impoverished.


Sterling K. Webb
-------------------------------------------------------------------
----- Original Message -----
From: "Ron Baalke" <baalke_at_zagami.jpl.nasa.gov>
To: "Meteorite Mailing List" <meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, August 22, 2006 6:44 PM
Subject: [meteorite-list] Pluto Seems Poised to Lose Its Planet Status


>
> http://www.nytimes.com/2006/08/22/science/space/22cnd-pluto.html
>
> Pluto Seems Poised to Lose Its Planet Status
> By DENNIS OVERBYE
> New York Times
> August 22, 2006
>
> Pluto was looking more and more like a goner today as astronomers
> meeting in Prague continued to debate the definition of a planet.
>
> "I think that today can go down as the 'day we lost Pluto,'" Jay
> Pasachoff of Williams College said in an e-mail message from Prague.
>
> Under fire from other astronomers and the public, a committee appointed
> by the International Astronomical Union revised and then revised again a
> definition proposed last week that would have expanded the number of
> official planets to 12, locking in Pluto as well as the newly discovered
> Xena in the outer solar system, as well as the asteroid Ceres and
> Pluto's moon Charon.
>
> The new definition offered today would set up a three-tiered
> classification scheme with eight "planets"; a group of "dwarf-planets"
> that would include Pluto, Ceres, Xena and many other icy balls in the
> outer solar system; and thousands of "smaller solar system bodies," like
> comets and asteroids.
>
> The bottom line, said Owen Gingerich, the Harvard astronomer who is
> chairman of the I.A.U.'s planet definition committee, is that in the new
> definition, "Pluto is not a planet."
>
> "There's not happiness all around, believe me," he added.
>
> The new proposal was hashed out in a couple of open meetings, the first
> of which was described by participants as tumultuous, and the second
> more congenial. Astronomers are supposed to vote on this or some other
> definition on Thursday, but whether a consensus is emerging depends on
> whom you talk to. Some astronomers expressed anger that the original
> definition of planet had been developed in isolation and then dropped on
> them only a week before the big vote. Others continued to question
> whether it was so important to decide the question now at all.
>
> Among its defects, some astronomers say, the newer definition abandons
> any pretense of being applicable to other planetary systems beyond our
> own solar system.
>
> To many astronomers, Pluto's tiny size and unusually tilted orbit make
> it a better match to the icy balls floating in the outskirts of the
> solar system in what is known as the Kuiper Belt than to the
> conventional planets like Jupiter and Mars. The issue has been forced on
> astronomers by the discovery of such a ball even larger than Pluto,
> nicknamed Xena by its discoverer, Mike Brown of the California Institute
> of Technology.
>
> If Pluto is a planet, so should be Xena, Dr. Brown has argued.
>
> The committee's original prime criterion was roundness, meaning that a
> planet had to be big enough so that gravity would overcome internal
> forces and squash it into a roughly spherical shape. But a large
> contingent of astronomers, led by Julio Fernandez of the University of
> the Republic in Montevideo, Uruguay, has argued that a planet must also
> be massive enough to clear other objects out of its orbital zone. Dr.
> Gingerich admitted, "They are in control of things."
>
> So the newest resolution includes the requirement for orbital dominance
> as a condition for full-fledged planethood, Dr. Gingerich said. That
> knocks out Pluto, which crosses the orbit of Neptune, and Xena, which
> orbits among the icy wrecks of the Kuiper Belt, and Ceres, which is in
> the asteroid belt.
>
> "Vociferous objectors have said they could accept this," Dr. Gingerich
> said.
>
> Reached in his office at Caltech, Dr. Brown, who as the discoverer of
> Xena has the most to lose by its and Pluto's demotion, said he thought
> he could live with the new proposal. "It essentially demotes Pluto to
> something other than a real planet, which is reasonable," he wrote in an
> e-mail.
>
> Dr. Gingerich cautioned that there were many things still to be sorted
> out. For example, the International Astronomical Union might consider
> creating a special name for Pluto and other dwarf-planets, like Xena and
> others yet to be discovered, that dwell out beyond Neptune. If it did,
> he said that "plutonians" seemed like a likelier choice than the
> previous suggestion, "plutons." That term was protested by geologists,
> who pointed out that it was already used in earth science for nuggets of
> molten rock that have solidified and reached the surface.
>
> But with two more days before the scheduled vote, there was no guarantee
> Pluto would not make a comeback and the definition of planethood be
> rewritten again.
>
> "Some people think that the astronomers will look stupid if we can't
> agree on a definition or if we don't even know what a planet is," Dr.
> Pasachoff said. "But someone pointed out that this definition will hold
> for all time and that it is more important to get it right."
>
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Received on Tue 22 Aug 2006 10:30:10 PM PDT