[ExI] Tabby's star

Tue Dec 13 17:00:59 UTC 2016

From: extropy-chat [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of John Clark
Sent: Tuesday, December 13, 2016 7:18 AM
To: ExI chat list <extropy-chat at lists.extropy.org>
Subject: Re: [ExI] Tabby's star

On Mon, Dec 12, 2016 at 12:07 PM, spike <spike66 at att.net <mailto:spike66 at att.net> > wrote:

> >…If we gather all the metals available in the system into one big lump, we end up with a sphere perhaps thrice to five times the diameter of the earth…

>…I think the consensus is Jupiter does a rocky core and its between 12 and 45 times earth's mass…   John K Clark

Ja I heard Saturn might have a core as well.  I will settle for anything that gets the total rocky mass to anywhere between 1E26 and 1E27, then pick your favorite order of magnitude.  My guess is 27 is the right OoM.

Step one in any engineering exercise is the bound the problem.  Having all the rocky mass together in one lump is one extreme which trades away everything for proximity: latency is minimized.  With that solution, it maximizes heat control problem, since every bit that is flipped way down below the surface needs to have the resulting heat hauled all the way up to the surface and radiated away.

We can imagine splitting the mass into two closely-orbiting masses, or ten perhaps and see that in exchange for accepting some additional latency, we get more surface area, more access to cold space for radiating heat, less wasted matter which is under too much pressure to make computing material.  It is easy enough to imagine a stable orbit with those ten spheres, or a hundred earth-sized spheres orbiting in a plane evenly spaced 3.6 degrees apart at 1 AU, so latency about 30 seconds between them, about half an hour latency between to two nodes opposite the star assuming relayed transmission.

Now we can repeat the thought experiment assuming 1000 rocky masses, each with about a Mercury mass, about 3 seconds latency between two adjacent nodes, 10k masses with about a lunar mass each, and so on.

With that thought experiment, it quickly becomes clear that (from my understanding of what computronium would be for) the solution assuming FERP is getting better as we divide the masses by ten and multiply their number by one OoM.  We can also clearly see there is a logical endgame: at some point the individual nodes get too small.  But starting at one big rocky lump and working down is helpful.

Starting at dust-sized particles and moving up is more difficult methinks, but I am listening if someone here has the expertise to start imagining a reasonable scenario starting on that end.

spike 

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