[ExI] Alien Civilizations May Only Be Detectable For A Cosmic Blink Of An Eye

[Keith Henson]

"That's why I think, at least in the observable universe, we are alone. "

That's what I thought until the astronomers found almost 2 dozen
blinking stars in a 2000 ly volume around Tabby's Star.  One is most
likely natural; 24 just has to be intentional.  The AIs guess they
have been in space for 3000 years, which gives them a spread rate of
1/3 of C.  The closest one is 511 ly from us.  The biggest dip
corresponds to an object 509 times the area of the Earth.  I posted
the analysis here more than a year ago.



Keith

On Fri, Oct 17, 2025 at 1:20 PM John Clark via extropy-chat
<extropy-chat at lists.extropy.org> wrote:
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> On Fri, Oct 17, 2025 at 3:27 PM spike jones via extropy-chat <extropy-chat at lists.extropy.org> wrote:
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>> <https://www.universetoday.com/articles/alien-civilizations-may-only-be-dete
>> ctable-for-a-cosmic-blink-of-an-eye>
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> That makes absolutely no sense to me! What does AI have to do with it? It makes no difference if the brain that develops Drexler style Nanotechnology is wet and squishy or dry and hard because then they could make a von Neumann probe, and even if they couldn't move them faster than 0.001 C, which they almost certainly could, they could send one to every star in the galaxy in less than 50 million years (a blink of the eye cosmically speaking) and then a blind man in the fog bank could tell that the galaxy had been engineered. But even with our most powerful telescopes we've never seen a hint of such a thing. That's why I think, at least in the observable universe, we are alone.
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>  John K Clark
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