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From: dipper@utastro.UUCP (Debbie Byrd)
Newsgroups: net.astro
Subject: StarDate: August 25 On To Neptune
Message-ID: <602@utastro.UUCP>
Date: Sun, 25-Aug-85 02:00:24 EDT
Article-I.D.: utastro.602
Posted: Sun Aug 25 02:00:24 1985
Date-Received: Thu, 29-Aug-85 06:05:55 EDT
Organization: U. Texas, Astronomy, Austin, TX
Lines: 43


On this date in 1989, the Voyager spacecraft may make a first encounter
with Neptune.  More -- after this.

August 25  On To Neptune

Yesterday we talked about the upcoming Voyager 2 spacecraft encounter
with the planet Uranus -- due to take place this coming winter.
Voyager has been in space now for eight years -- and it's showing signs
of old age.  But if it survives past the encounter with Uranus, it will
go on to encounter Neptune.  Closest approach would be on this date in
the year 1989 -- just five days beyond the 12th anniversary of the
launch of Voyager 2.

Neptune has long been regarded as a near twin to the planet Uranus.
There's a great riddle concerning the question of rings for the planet
-- since Neptune is now the only gas giant world NOT known to have
them.  There's evidence that Neptune does have rings.  Voyager 2 would
tell us for sure.

It so happens that Neptune is now the most distant from the sun of all
known worlds in our solar system.  That has been the case since 1979,
when Pluto's orbit brought it closer to the sun than Neptune.  Pluto
will orbit inward from Neptune until the end of this century.

Neptune has two known moons -- large Triton and little Nereid -- and
there are suggestions of a possible third moon from ground-based
observations made in 1981.  The large moon, Triton, is a fascinating
world in itself -- almost as large as the planet Mercury -- with a
possible ocean of liquid nitrogen on its surface!

If all goes well, Voyager 2 will explore distant Neptune and its moons
-- with closest approach on today's date in 1989.



Script by Deborah Byrd.





(c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin