[ExI] Eternity in six hours: intergalactic spreading of intelligent life and sharpening the Fermi paradox
John Clark
johnkclark at gmail.com
Tue Sep 10 14:35:00 UTC 2013
On Tue, Sep 10, 2013 Andrew Mckee <andymck35 at gmail.com> wrote:
>> I think we could probably detect a Dyson sphere with its distinctive
>> infrared signature if it were within several thousand light years of us,
>> and we could see a galaxy of Dyson spheres if there were one anywhere in
>> the observable universe. But we see nothing.
>>
>
> > I wonder how water tight the idea is - that Dyson spheres would emit
> infrared radiation?
>
If the first law of thermodynamics is correct then the amount of energy
emitted from a Dyson sphere into space would be equal to the amount of
electromagnetic energy the naked star would have emitted if the sphere were
not there. And if the second law of thermodynamics is correct then the
frequency of those emitted electromagnetic waves will be shifted downward
from visible light and ultraviolet into the infrared, or perhaps even more
into microwaves.
Incidentally if there were one of our laws of physics that I think even a
civilization a billion years more advanced than ours would find just as
true as we do it would be the second law of thermodynamics. The first law,
the conservation of energy, is just a empirical observation, we've never
seen it violated and use induction to conclude that we never will. But the
second law is not like that, the second law is based on logic. In every one
of Everett's Many Worlds where 2+2 is still equal to 4 the second law holds
true.
> Maybe dark matter is Dyson spheres whose inhabitants have figured out
> perfect or near perfect complete thermal management
We know very little about Dark Matter but one thing we do know is that it
doesn't interact with electromagnetic waves, that's why it's so hard to
detect.
John K Clark
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