[ExI] Scientists discuss why we might not spot extraterrestrial civs

[Keith Henson]

On Sat, Aug 3, 2024 at 7:25 AM BillK via extropy-chat
<extropy-chat at lists.extropy.org> wrote:
>
> n Sat, 3 Aug 2024 at 00:21, Keith Henson <hkeithhenson at gmail.com> wrote:
> >
> > On Fri, Aug 2, 2024 at 1:39 PM BillK via extropy-chat
> > <extropy-chat at lists.extropy.org> wrote:
> >
> > snip
> >
> > > A "Surely a society that can place enormous
> > structures in space would be able to access nuclear fusion or other
> > space-efficient methods of generating power."
> >
> > That's silly.  They have a star, and thermal power plants will let
> > them capture 40 to 60%
> >
> > Keith
> -----------------------------------------------
>
>
> I'm not sure what you are trying to say. Why is it silly?

If you are in space, building a fusion energy source is just silly.
You have a star for energy.

> To build a Dyson sphere will require tremendous resources in material
> and energy.

It is possible to build a Dyson sphere, but I don't think it makes
sense.  Orbiting structures do.

> It will be at least another 1,000 years before humans can even
> consider a huge project like that.

We are considering it right now.  As you know, I think we can see one
crossing the disk of Tabby's Star.

> At present, we are installing solar panels and batteries everywhere to
> supply energy (and these are improving every year).
> Within ten years we will have advanced AI and in probably 20 years,
> fusion energy power plants will be developed.

Fusion plants *might* make sense on the surface, but if we or our AI
descendants move into space, no.  The big problem is getting rid of
the waste heat.  Which is why you will find them in the computational
zone rather than the habitable zone.

> What other energy
> sources might be developed in 100 or 1,000 years?

Not likely.  We understand energy.

> Anti-matter engines?  :)

Just no.

> If by then we already have developed enough energy sources on Earth,
> why would we want to dedicate the whole planetary resources to building a Dyson
> sphere?
> This logic applies to every developing civilisation. That is what the
> scientist from NASA Goddard and American University is referring to.
> It seems a very reasonable idea to me.

Regardless of whether what we see at Tabby's Star is aliens, it got me
thinking about where a civilization would move to in a star system.
You want cold to run computers at low error rates, but you need energy
as well.  It turns out that the equilibrium is around 5 AU for our
system.  The other factor is the speed of light,  The place should be
as small as possible for communications.

Keith

> BillK
>
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