[ExI] SETI reviews the Drake equation

Stuart LaForge avant at sollegro.com
Fri Feb 1 18:25:43 UTC 2019

Quoting BillK quoting Seth Shostak quoting Francis Drake:

> Quote:
> And in any case, Drake argues that deliberate colonization might be
> “The spreading of intelligent life from one star system to another
> would probably not appeal to truly intelligent creatures,” he says,
> “once they calculate that, even travelling at, say, only one-tenth the
> speed of light, it takes more than a million times more energy to
> establish a colony around another star than required to establish one
> of the same size near their own. There is plenty of material available
> in the satellites and asteroids of stellar environments, assuming they
> resemble ours, to create a multitude of habitable, planet-like abodes
> right at home.”

Drake seems to imply here that the Great Filter is simple laziness.
That is that, we don't see interstellar civilizations because they
don't want to expend the energy to travel to other star systems. Of
course, such civilizations would be brittle as they would not be able
to survive the death of their own stars. It does fit the observation
of the Great Silence but it doesn't sound as "truly intelligent" as he
suggests. Especially if building a large collection of local colonies
uses up all the energy that would otherwise be available to spread to
other star systems. Being overly dependent on a single star still
counts as "putting all of ones eggs in the same basket" IMO.

Also, it is far preferable to be the colonizers than the colonized. So
why risk another civilization out there being less than "truly

> As for panspermia, he notes that “it would be far more efficient to
> send by radio the data to replicate the creature's DNA, to clone
> duplicates of themselves.”

This is also unlikely to be effective because like any other form of
information, the meaning of DNA sequences are context dependent.
Assuming that the radio message could be recognized by ET as a DNA
sequence at all, it is not at all certain that extraterrestrial life
would use the same "genetic code" as earth life. To a certain extent,
the tRNA codons that allow our DNA to be translated into proteins are
arbitrary and completely dependent on the common ancestry of all
terrestrial life.

So in other words, beaming DNA sequences across the galaxy by means of
radio waves would only be a feasible alternative to panspermia if
panspermia were actually the true origin of life on earth and all life
in the galaxy had a common ancestor. Of course, if panspermia were
true, then what's the point of an alternative that is dependent on the
charity of intelligent aliens to reconstitute an unknown organism
based entirely on its DNA sequence?

I mean would we try to clone an DNA sequence we received by radio from
an ET civilization? That is the premise of the movie "Species" which
was science fiction - horror after all.

Stuart LaForge

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