[ExI] Tabby's star
spike66 at att.net
Mon Dec 12 17:07:56 UTC 2016
From: extropy-chat [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of spike
Subject: Re: [ExI] Tabby's star
From: extropy-chat [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of John Clark
>…John we have a lot of work to do on your notion of the information content of a volume of space being a function of the surface area of the sphere. That in itself has some profound consequences. As the sphere scales up, the information content increases as the square while the latency increases linearly. That observation requires deep thought…spike
OK we are ready to do a thought experiment.
In marketing, we have a price-point curve where the endpoints are zero: set the price of your product too high, your profit per sale is high but you make nothing because your competitor eats your lunch with a lower price. Set the price too low and you make nada because your profit per sale goes to nothing.
Let us do a thought experiment from the point of view of a lifeform which figured out how to get out into space from a deep gravity well, figures out how to do advanced nanotech to make optimal computing devices or anything else it wants to make. Assume away all engineering problems: this thought experiment allows fantasy engineering but not fantasy physical constraints, including known laws of thermodynamics. I anticipate future thought experiments with those conditions, so I propose the term FERP for fantasy engineering, reality physics.
Given that, we can create something analogous to a marketing price-point curve where we balance computational energy efficiency with latency in a planetary system.
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. Last I heard, it is still unknown if Jupiter has a rocky core, so there is plenty of uncertainty in this analysis, so let us assume all the metals combined, throwing away the hydrogen and all noble gases but sweeping up all the Oort cloud, asteroid belt, possible rocky cores of gas giants, small debris, ice, dust, everything else here, makes a rocky core 4 earth radii and 200 earth masses to get us to about 1e27kg.
This is very clearly not the best arrangement for maximum computing efficiency under any FERP scenario I can imagine: way too much mass is too hot and under too much pressure to compute.
OK so let us imagine the other extreme, where all that E26kg of metal is widely separated into a cloud of the smallest practical unit of computing we can imagine. What is that? John? Is there some kind of 4 bit processor with about 32 bits of memory we could imagine as the lower extreme? I would estimate its mass at 1E-23kg, since we would need at least a few hundred atoms I would think to make such a device, even with the most extreme F in our FERP.
In that scenario we get about 1E50 processors in orbit, each small enough to be practically useless. With that many processors we need a lot of space, so our latency hit is enormous, particularly considering that processors that small don’t do much. Therefore they would be heavily dependent on communications with the others.
So far still ignoring thermodynamic considerations, we have bounded the problem of making optimal use of the metal and energy available in any star system, ja? Our unit of computing is somewhere between 1E27 and 1E-23kg.
Oy, that’s a lot of verbiage for bounding an optimal solution somewhere within 50 orders of magnitude.
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