From: Eliezer S. Yudkowsky (sentience@pobox.com)
Date: Thu Sep 21 2000 - 23:54:33 MDT
John Clark wrote:
>
> Only a moron would say there is no signal degradation at interstellar distances.
> I am not a moron. Speaking of morons, it would be interesting if somebody could
> come up with a more moronic way to communicate than neutrinos, well lets see,
> gravity waves would be pretty stupid, but perhaps not quite stupid enough. Come on,
> somebody out there must have a stupider idea.
Okay: Shout REALLY LOUD...
"Most people think Star Trek has solved the problem of faster-than-light
travel. I am much more fascinated by Star Trek's solution to the
sound-in-a-vacuum problem."
--Karen Lingel
On a more serious note, are we really sure that neutrinos can't be used for
communication? Suppose you had some way to aim the neutrino beam almost
perfectly, correcting for gravitational influences, so that you can pour a
beam into a 1mm-diameter cup orbiting another star. Suppose that you also
fire off a million neutrinos in a perfect two-dimensional grid, each neutrino
an infinitesimal bit to the side of the previous one, so that at least one
neutrino in the pattern is guaranteed to hit any atomic nucleus inside the
pattern's radius. Fire the beam at a crystal where the atomic spacing is less
than the pattern diameter, and at least one neutrino is guaranteed to hit.
The result could be an interstellar radio that shines effortlessly through any
amount of dust.
I have no idea whether this makes any sense from a physicist's perspective,
but my guess is "NO". The basic assumption seems to be that a really
perfectly aimed neutrino can be deliberately made to be absorbed by an atom,
and I don't know whether the penetrating quality of neutrinos derives from the
improbability of a perfect hit, or the improbability of absorption in any hit
(glancing or otherwise).
Is a detector made of neutronium more likely to get hit? Could you reverse
the patterned-neutrino theory and use patterned neutronium to guarantee a
hit? Or is that just not the way quantum neutridynamics work?
Neutrino-neutronium radio... ought to be a pun here...
This makes a nice little dialogue for a post-Singularity novel:
"You communicate with Andromeda? How?"
"Oh, we send out a sequence of neutrinos; a neutrino strikes
a chlorine atom and turns it into argon, that's a 'one'..."
"But can't a neutrino pass through ten light-years of lead
without being absorbed?"
"We aim them really carefully."
-- -- -- -- --
Eliezer S. Yudkowsky http://singinst.org/
Research Fellow, Singularity Institute for Artificial Intelligence
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