[ExI] Von Neumann Probes

[Jason Resch]

On Tue, Jan 27, 2026, 9:27 AM John Clark <johnkclark at gmail.com> wrote:

> On Tue, Jan 27, 2026 at 8:03 AM Jason Resch via extropy-chat <
> extropy-chat at lists.extropy.org> wrote:
>
> *>> So ET is so obsessed with wringing ever last joule of energy out of
>>> their heat engine that they **think** the 2.7 degree temperature of the
>>> Cosmic Microwave Background Radiation isn't cold enough so they use a LARGE
>>> black hole as a heat sink instead to slightly improve the efficiency of
>>> their heat engine.*
>>>
>>
>> *> 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.

Jason


> *John K Clark*
>
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.extropy.org/pipermail/extropy-chat/attachments/20260127/dd4e5ac2/attachment.htm>