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<div class="gmail_default"
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2016-01-25 17:55, John Clark wrote:</div>
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<div><font size="4">And if it's a Dyson Sphere it's odd we
can't pick up any intelligent radio signals from it; the
star is only 1
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,</div>
480 light years away and the Arecibo Observatory could
detect a similar instrument 50,000 light years away but
we don't hear a peep. People have looked with optical
telescopes
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for</div>
flashes of LASER light coming from the vicinity of the
star and haven't found those either.</font></div>
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Even more compelling is the absence of IR emissions. If it had been
a Dyson shell we should have seen a fraction of the stars luminosity
reradiated in the IR spectrum. Aliens might keep silent for alien
reasons, but it is hard to cheat thermodynamics. <br>
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<pre class="moz-signature" cols="72">--
Anders Sandberg
Future of Humanity Institute
Oxford Martin School
Oxford University</pre>
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