[ExI] The Milky Way is probably full of dead civilizations

[BillK]

The Milky Way is probably full of dead civilizations
By Rafi Letzter  19 Dec, 2020

<https://www.livescience.com/milky-way-alien-life-map.html>

Quote:
That's the takeaway of a new study, published Dec. 14 to the arXiv
database, which used modern astronomy and statistical modeling to map
the emergence and death of intelligent life in time and space across
the Milky Way. Their results amount to a more precise 2020 update of a
famous equation that Search for Extraterrestrial Intelligence founder
Frank Drake wrote in 1961.

The authors looked at a range of factors presumed to influence the
development of intelligent life, such as the prevalence of sunlike
stars harboring Earth-like planets; the frequency of deadly,
radiation-blasting supernovas; the probability of and time necessary
for intelligent life to evolve if conditions are right; and the
possible tendency of advanced civilizations to destroy themselves.
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This last bit is the most uncertain variable in the paper; how often
do civilizations kill themselves? But it's also the most important in
determining how widespread civilization is, the researchers found.
Even an extraordinarily low chance of a given civilization wiping
itself out in any given century — say, via nuclear holocaust or
runaway climate change — would mean that the overwhelming majority of
peak Milky Way civilizations are already gone.
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The problem is the long timescales.  Can civilisations ever continue for
billions of years?

BillK