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From: dipper@utastro.UUCP (Debbie Byrd)
Newsgroups: net.astro
Subject: StarDate: February 18 The Discovery of Pluto
Message-ID: <384@utastro.UUCP>
Date: Tue, 18-Feb-86 02:00:20 EST
Article-I.D.: utastro.384
Posted: Tue Feb 18 02:00:20 1986
Date-Received: Wed, 19-Feb-86 03:34:12 EST
Organization: U. Texas, Astronomy, Austin, TX
Lines: 33

This is the anniversary of the discovery of Pluto.  More about it --
right after this.

February 18  The Discovery of Pluto

Around the beginning of this century, the search began for a planet
located beyond the orbit of Neptune.  Irregularities in the orbit of
Neptune sparked the search.  It was believed that some large planet
must be pulling on Neptune -- causing it to stray somewhat from its
otherwise predictable orbit around the sun.

Well, many people tried to calculate the orbit of the unknown planet --
most notably Percival Lowell.  And finally the new planet was found --
on today's date, in the year 1930 -- by Clyde Tombaugh of the Lowell
Observatory outside Flagstaff.  The planet was given the name Pluto,
for the mythological brother of Neptune -- an appropriate name also
since the first two letters are Percival Lowell's initials.

But Pluto's discovery introduced more mysteries than it solved.  For
one thing, Pluto isn't a giant planet, as many people had predicted.
Instead, it's extremely small -- smaller than Earth's moon.  Some
astronomers used to speculate that Pluto was in fact an escaped moon of
Neptune -- until Pluto was found to have its own moon -- discovered
just a few years ago.

What's more, Pluto is so small that it couldn't have caused the
deviations in Neptune's orbit -- which is what caused us to look for it
in the first place!  Today some astronomers are still searching for
another undiscovered planet -- an unknown member of the sun's family
located beyond the orbit of Pluto.

Script by Deborah Byrd.
(c) Copyright 1985, 1986 McDonald Observatory, University of Texas at Austin