[ExI] Von Neumann Probes

[John Clark]

On Wed, Jan 28, 2026 at 7:40 AM Jason Resch via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

*> Earlier you insisted energy consumption (i.e. power) was all important
> for running non-reversible computations (which it is).*


*Yes.*


> *> And this was your reason for concluding it was obvious ETI would build
> Dyson swarms.*


*Yes.*


> * > Now, when I show there were better ways, you seem to forget this, *


*You are absolutely correct, I have forgotten that. I don't know what
you're talking about.  *

*> and retreat to citing an unrelated fact we all agree on.*


*So we both now agree that your comment about Black Holes improving the
efficiency of a solar heat engine by many billions of times was silly?  *

*> I have to conclude you're just trolling at this point*


*Just a few days after I first joined this list in 1993 I was accused of
being a troll, so I guess I'm the oldest living troll in the world. Either
that or the accusation of being a troll is the only rebuttal that somebody
can think of.  *

* John K Clark*










>>>
>>>>> *> Ite not a "slight improvement." It's an efficiency improvement of
>>>>> many billions of times. Even a small black hole (a few meters across, with
>>>>> the mass of Jupiter) is 10^-8 degrees, so close to a billion times colder
>>>>> than background radiation. A galactic center black hole can be a trillion
>>>>> times colder than the background radiation. So it is not a "slight
>>>>> improvement in efficiency," it's equivalent to being able to perform
>>>>> billions or trillion of times as many non-reversible computations for the
>>>>> same expenditure of energy.*
>>>>>
>>>>
>>>> *Nope, you'd barely increase the efficiency at all. The Carnot
>>>> Efficiency (X) depends entirely on the temperature of your heat source (Th)
>>>> and your cold sink (Tc), formula is: *
>>>>
>>>> *X=1- Tc/Th*
>>>>
>>>> *The surface of the sun is at 5,800 K and the CMBR is at 2.7K, and
>>>> you're right that a Black Hole with the mass of Jupiter would have a
>>>> temperature of about **10^-8 K, so let's plug in some numbers: *
>>>>
>>>> *If we use the CMBR as the cold sink then*
>>>>
>>>> *X= (1-(2.7/5800) = 0.99353 efficiency *
>>>>
>>>> *If there was something that was just twice as efficient then you'd
>>>> have something that was nearly 200% efficient, in other words you'd have a
>>>> perpetual motion machine. And you were talking about something that was
>>>> many billions of times more efficient.   *
>>>>
>>>>
>>>> *Now let's look at what would happen if we used a Jupiter mass black
>>>> hole for the cold heat sink:*
>>>>
>>>> *X = 1 - 0.00000001/5,800 = 0.9999999999983 efficiency *
>>>>
>>>> *To summarize, if you use empty space as your cold heat sink you'd only
>>>> lose about 0.047% of your energy, and I think that's pretty damn good. If
>>>> you use a Jupiter size black hole as your cold sink you'd lose about
>>>> 0.00000000017% of your energy. Doesn't  seem worth all the trouble to me,
>>>> and I wonder where you'd get the vast amount of energy necessary to
>>>> compress Jupiter into a black hole. I think ET should be more concerned
>>>> with trillions upon trillions of suns radiating all that nice juicy energy
>>>> uselessly into infinite space. *
>>>>
>>>
>>> *> Now work out the number of non reversible computations that can be
>>> performed under the two efficiencies you calculated.*
>>>
>>
>> *The maximum number of bits any physical object can compute depends on
>> how massive it is. No computer, regardless of its serial or parallel, can
>> compute more than 1.36*1^50 bits per second per kilogram.*
>>
>
> You are avoiding my question.
>
> Earlier you insisted energy consumption (i.e. power) was all important for
> running non-reversible computations (which it is). And this was your reason
> for concluding it was obvious ETI would build Dyson swarms.
>
> Now, when I show there were better ways, you seem to forget this, and
> retreat to citing an unrelated fact we all agree on. I have to conclude
> you're just trolling at this point, or suffering some severe form of
> cognitive dissonance.
>
> Jason
>
> P.S.
> You have also forgotten the 4X improvement over Bremmermann's limit as
> shown by Margolus and Levitin, which you earlier acknowledged when you said
> "4E/h"
>
>
>
>> *John K Clark*
>>
>>
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