Re: Beyond Neptune

From: John Clark (
Date: Tue Jul 03 2001 - 11:09:55 MDT

Lee Corbin <> Wrote:

> I don't get it. I thought that Pluto's existence, like Neptune's,
> had been deduced by pertubative effects on the other planets.

The existence and position of Neptune was indeed deduced by
observing slight variations in the orbit of Uranus. Then, at the vary
limit of what was observable at the time, they thought they saw an
extremely tiny variation in the orbit of Neptune. They figured out
where the next planet must be to produce that effect, pointed their
telescopes in that direction and sure enough there was Pluto.
However it turns out to be one of the greatest coincidences in the
history of science, the mass of Pluto is far to small to cause any
measurable change in the orbit of Neptune. Oh well, they say it's
better to be lucky than smart.

     John K Clark

This archive was generated by hypermail 2b30 : Fri Oct 12 2001 - 14:39:41 MDT