Definition Trouble

Pity the poor International Astronomical Union.

In the course of kicking Pluto out of the planetary club they made an error in phrasing which turns out to exclude all other planets outside the Solar System. The definition of a planet adopted by the I.A.U. in 2006 specifies that it is a body "orbiting the Sun" -- which of course rules out bodies orbiting other stars. Trouble is, we've now found 429 planets -- or whatever we're supposed to call them -- orbiting other stars.

So now the organization has a difficult choice to make. They can keep the definition as is, thereby excluding a growing number of planets, many of which dwarf anything in the Solar System, and leaving astronomers who study extrasolar planets without a proper term for the things they're observing. Or they can re-open the planetary definition can of worms, with the highly vocal Pluto lobby enlisting schoolchildren and state legislators to lobby for their favorite iceball.

Ah, well, at least they get some public attention. How often do you have intense public debate over decisions about nomenclature made by scientific societies?