[ExI] SETI reviews the Drake equation

BillK pharos at gmail.com
Sat Feb 2 00:12:44 UTC 2019

On Fri, 1 Feb 2019 at 19:39, Stuart LaForge <avant at sollegro.com> wrote:
> 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
> intelligent"?
> 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

Our sun is approximately middle-aged and should remain fairly stable
for about another 5 billion years. So I think we can safely put
dealing with the problem of the sun dying fairly far down on our
'To-Do' list. Our species should change drastically way before then
and we may not even still be DNA based life forms.

I agree that beaming DNA data out to nearby star systems seems
pointless to me also. Radio is the fastest method of transmission we
know of, so if AI scout ships are sent out at one-tenth of light speed
it would seem sensible to keep them updated and receive transmissions
back from them.

But I do agree with Drake that there is a plenty of development
potential within our own goldilocks zone to keep us busy protecting
earth and expanding into other local space habitats so that humanity
is not solely based on earth. The risk of asteroid strikes, pandemics,
etc. needs dealing with first.
Interstellar travel is really expensive unless we discover unlimited
power resources. Though unlimited resources plus exponential change
should make far future speculation pretty much an 'anything is
possible' type discussion.  :)


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