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Path: utzoo!linus!decvax!dartvax!quark
From: quark@dartvax.UUCP
Newsgroups: net.physics
Subject: Re: The \"I Love Lucy\" Problem.
Message-ID: <311@dartvax.UUCP>
Date: Thu, 27-Oct-83 08:03:23 EDT
Article-I.D.: dartvax.311
Posted: Thu Oct 27 08:03:23 1983
Date-Received: Fri, 28-Oct-83 02:18:27 EDT
References: houxy.148
Lines: 19

this is more of an engineering problem (for the hypothetical
receiving civilization) than a physics problem. the I Love Lucy
signal propagates at nearly the speed of light in vacuum. by
further assuming that the initial broadcast 
was/is spherically symmetric with respect to the (point-like
source) earth, it is easy to calculate the photon density per
area of spherical shell after any given time (given in addition
the initial intensity of the broadcast). it's then just a matter
of building a large enough detecting device given the sensitivity
of the materials used in the detector. if i remember correctly,
i or a friend did a calculation some time ago with the result
being that given the relatively low broadcast intensity, it would
be only several tens of light years before the signal lost enough
information to become meaningless.
 
the real problem is, however, that if a civilization did pick up
the signal and saw a few episodes, they would probably assume
that there was no intelligent civilization in this corner of
the galaxy.