Don Sheldon wrote:
I had thought that the definition of "planet" was changed and happend
to no longer include Pluto. Am I mistaken?
The IAU never used to have its own "official" definition of "planet",
it was just a normal English word that everybody had understood for
thousands of years, and there was no need for a technical definition.
When Ceres was mistakenly thought to be a planet there was no need for
a technical definition, and when 50 years or so later people realised
that that had been a mistake they still didn't feel the need for any
technical definition. Then when Pluto was added they still didn't
need a definition.
But when it became increasingly obvious that Pluto ought to go the same
way as Ceres, and for the same reasons, some people objected that there
wasn't an official IAU definition, and who's to say what a planet is
anyway. So they argued about a definition, and tried to come up with
artificial ones that would somehow magically keep Pluto while excluding
Ceres and Xena (yeah, I know, Eris, whatever), and they failed.
The fact remains that had people known in 1930 what we now know about
Pluto, it would never have been called a planet in the first place.
Zev Sero Something has gone seriously awry with this Court's
zev@xxxxxxxxx interpretation of the Constitution.
- Clarence Thomas