[ExI] Fermi Paradox and Transcension

[spike]

-----Original Message-----
From: extropy-chat-bounces at lists.extropy.org
[mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of Keith Henson


>>...  If it is absorbing a significant portion of the energy of the star,
it is either jet off somewhere or cook.

>...That I really don't understand.  If you were to enclose the sun in a one
AU Dyson shell, the equilibrium temperature on the outside would be around
127 deg C.

Ja, but portions of the inner layers of an MBrain get warmer than that.  I
have tried to model this a few different ways, and I end up with a
surprising result: an MBrain cannot collect a large portion of the energy
from a star.  Otherwise the inner nodes cannot reject sufficient heat to
stay in the temperature range in which electronic devices we know today
would work long term.  The problem is that I don't trust any of my models.
I need to create a digital model with actual numbers on attitude
determination and control, see what our worst cases are.

>>... I don't know of an online explanation of that concept.  I might need
to write one.

>...I would like to see that.

Me too.  I need to finish writing up proposals (Three down, 16 to go.)

>...If you are trying to think fast, your physical layer needs to be as
small as you can get it... Keith

Ja, and its temperature goes up linearly as the inverse of the radius of
orbit, all else being equal.  The problem is that all else is not equal when
you start moving inboard closer to the star.  I am surprised at how
complicated this question becomes, but it explains why there aren't already
a jillion thermal models out there on the web.  Rather than materials
availability, manufacturing or lifting the finished nodes to interplanetary
orbit, heat management may be the biggest technical hurdle for an MBrain.
Either that or I am missing something fundamental.

Parting shot: if an MBrain is mostly transparent and relies on a mostly
unobstructed view of cold space for heat rejection, such that we could see
through an MBrain without much loss of light, and if it is fundamentally
necessary that all MBrains must be constructed this way, this would explain
why we haven't seen the signature of one anywhere.  We would be looking for
a large cool object, when in fact an MBrain would be a dense hot object with
a nearly invisible misty haze around it that would look a lot like a dust
ring.  If we go with the Outback Postcards explanation for why we don't get
signals from the MBrains (because the interesting stuff is all happening
right there and they don't care about anything out here, and don't bother
sending postcards to Aborigines during wicked cool technical talks) and
MBrains must be mostly transparent, the universe could be filled with
MBrains and we wouldn't know it.

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