From: "Andy Robertson" 
Subject: Re: (urth) Thoughts on Undines, and other ramblings
Date: Mon, 17 Jun 2002 05:32:34 +0100

----- Original Message -----
From: "Alice K. Turner" 
> One final ramble:  By the end of our series, Severian is but
> one AU from the source of his power, and is probably going
> to have a hard time dying, even of old age.  He may grow really, really
bored.

>What is an AU?


An Astronmical Unit.  The average distance between the Urthand the Sun.
93,000,000 miles and some odd.   It is very easy to determine the size of
the solar system in terms of this unit, with a simple telescope/sextant, but
it was actually not so easy to determine exactly what this unit was until
echo-radar ranging of the planets was available .


    hartshorn




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