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From: Lynn.es@PARC-MAXC.ARPA@sri-unix.UUCP
Newsgroups: net.space
Subject: Re: Gold disk sent out of solar system
Message-ID: <4779@sri-arpa.UUCP>
Date: Thu, 1-Sep-83 13:39:56 EDT
Article-I.D.: sri-arpa.4779
Posted: Thu Sep  1 13:39:56 1983
Date-Received: Sun, 4-Sep-83 23:28:23 EDT
Lines: 26

The gold disks were on the Voyagers (1 and 2), had recordings of sounds 
and sights of earth on them, and are not what you are describing.  The 
gold-anodized aluminum rectangular plaques have the drawings you refer 
to, and were on Pioneers 10 and 11.  

The binary numbers are represented by ones for ones and dashes for zeros.  
They are used in four places on the plaques.  1) There is a one by the 
drawing of hydrogen atoms emitting their characteristic wavelength (21 cm).  
This is to show that this is the time and distance unit for the other 
numbers.  2) There is an eight (1---) next to a dimension (of 8 x 21 cm) 
on a picture of the spacecraft and people.  This gives the size of the 
people and double checks the size units against the spacecraft itself.  
3) There are large binary numbers giving the periods (in units of the 
time period of 21 cm hydrogen) of 14 prominent nearby pulsars.  4) The 
distances from the sun to each of the nine planets is given in weird 
units (approx 0.039 AU). 

The directions and relative distances of the pulsars are given by a 
diagram.  The positions and periods would allow determination of the 
location of our system within several light years and the time of launch 
within a year (because pulsar periods increase with time).  The diagram 
of the planets would allow precise identification of the sun and earth.  
More info on the plaques is in one chapter of "The Cosmic Connection" 
by Carl Sagan.

/Don Lynn