SpaceBanter.com - View Single Post - Planetary System Arbitrarily and Needlessly Changed By Bush Administration: Pluto Demoted

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Ryd wrote :

Pluto has been a planet for thousands of years....it was a perfectly
good and usable determination for everyone.

It took the Bush administration to suddenly change that. Why? For some
godforsaken political strategy masterminded Karl Rove, no doubt.

Nope. It is undoubtebly the result of pressures from Al-Qaeda, which
couldn't tolerate an american discovered planet...

Going 'round and 'round on defining Pluto
By Chet Raymo | August 28, 2006

SPARKS FLEW LIKE a meteor shower as the International Astronomical
Union, meeting in Prague, wrestled with the definition of a planet.

At first it looked like the number of planets might be increased to 12,
with the familiar nine joined by Pluto's moon Charon (classified as
part of a double planet); by Ceres, an object about half the size of
Pluto between Mars and Jupiter; and by a newly discovered object beyond
Pluto, UB313. Howls of indignation! Almost no one liked the proposal,
including many astronomers. The idea of a potentially endless stream of
distant, tiny planets waiting to be discovered was politically
untenable.

So the IAU backtracked. Ceres and UB313 reverted to minor planet status
and, to be consistent, Pluto was demoted, too. The number of planets in
the solar system would henceforth be eight, Mercury to Neptune, with no
more likely surprises.

What's going on? Why can't the IAU leave well enough alone? Why did we
waste all that time as kids memorizing the nine planets only to have
our cosmic merry-go-round thrown into chaos?

A tempest in a teapot?

Not really. It's a matter of making language more precise.

Pluto is half the size of Mercury. Ceres is half the size of Pluto. Why
call Pluto a planet and not Ceres? The choice is arbitrary. And what
about new objects beyond Pluto that have been and will be discovered?
Are they planets? Where do we draw a line that is not arbitrary?

A planet, according to the first definition proposed by the IAU, is an
object that orbits a star and is large enough for its own gravity to
give it a spherical shape. That brings Ceres and UB313 into the fold,
and perhaps other yet undiscovered objects in the far, dark corners of
the solar system.

When this definition proved unacceptable, the astronomers needed a
standard that weeds out Ceres and UB313 and closes the door to future
additions. So the IAU's final definition adds the condition that an
object be large enough to have cleared its neighborhood of other major
debris. This denies Ceres planethood -- it is embedded in the asteroid
belt -- and presumably also rules out UB313, out there in the dusty,
cluttered attic of the solar system. But it chops Pluto from the ranks
of planets, too; its orbit swings wildly inside the orbit of Neptune.
And if Pluto goes, so goes Charon.

The great 18th-century botanist Carl von Linné, better known by his
Latinized name Carolus Linnaeus , taught us that nothing is well
described unless well named, and that nothing is well named until well
described. Naming and exact description go hand and hand, and, if
carefully done, reveal patterns implicit in nature itself.

Does a dolphin have more in common with a shark or a Chihuahua? Is a
mouse more closely related to a gecko or an elephant? Common names tell
us nothing about biological relationships. The scientific naming system
pioneered by Linnaeus -- kingdom, phylum, class, order, family, genus,
species -- makes kinship manifest, and paved the way for Darwin's
theory of evolution.

After Linnaeus proposed his new nomenclature for biology, the Frenchman
Antoine Lavoisier set out to do much the same for chemistry. In the
preface to his great work ``Elements of Chemistry," Lavoisier tells us:
``Thus, while I thought myself employed only in forming a nomenclature,
and while I proposed to myself nothing more than to improve the
chemical language, my work transformed itself by degrees, without my
being able to prevent it, into a treatise upon the Elements of
Chemistry."

Lavoisier quotes the philosopher Etienne Condillac : ``We think only
through the medium of words. . . . The art of reasoning is nothing more
than a language well arranged."

That's what's going on with the IAU. Astronomers are trying to get
their language well arranged, trying to settle on definitions that will
facilitate the study of our solar system and planetary systems around
other stars. Exact language has proved itself a royal road to
discovery. Those of us who have become attached to Pluto as a planet
will just have to adjust.

http://www.boston.com/news/globe/edi...efining_pluto/