[ExI] About 3, 000 Years for a Reply From Intelligent Civilizations

BillK pharos at gmail.com
Tue Aug 10 22:47:34 UTC 2021

A new study discusses the possibility that by the time a message is
received by an intelligent species, the civilization that sent it will
be long dead.


Taking their cue from the Copernican Principle, which states that
humanity and Earth are representative of the norm (and not an
outlier), they calculated that if any transmissions from Earth were
heard by an extraterrestrial technological civilization (ETC), it
would take about 3000 years to get a reply.

This conclusion is supported by previous research (conducted with the
help of Dr. Frank Drake himself!) that indicated that within various
parameters, a call-and-answer scenario would take longer than the
average civilization’s lifespan. In other words, any signals we
receive from an ETC (whether they are a response or an attempt to
“start a conversation”) are likely to have been sent by a species that
has since become extinct.

Yes, I have been thinking recently that there are probably only a few
advanced civilisations in each galaxy, spread so far apart that
contact between civs is very unlikely.


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