Ancient Stars (and a Thought on SETI)

centauri-dreams.org

17 points·JPLeRouzic··4 comments

Although I generally agree with the notion that the probability of two civilizations meeting each other is extremely low. I think there are factors that can improve it.

Even if a civilization only survives say 1 million years, it can definitely leave something that emits messages for a much longer period of time.

Now if we accept the previous point, and calculate the number of planets that are suitable for creating life, the probability might improve to an acceptable number. It's no longer just a few light years, but maybe a billion light years -- if we believe residues of a dead civilization may survive that long.

How much power would such a device need to be detected above background radiation? Would a power source for it last long enough to improve the odds significantly?

Good question and I thought about it too after submitting the reply. I guess this is a real obstacle.

It need not be active to send a message. If you build a giant diamond cube or some other gigastructure, it could last for billions (?) of years even after the builders have become extinct. You need it to be detectable at interstellar distances, but the message is simply "we were here once." Maybe you could encode your civilization's knowledge on the gigastructure itself for visitors.

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