Talk:Matrioshka brain

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Efficiency
The nested Matrioshka brain is indeed the most energy efficient, but it's actually close to the worst mass-efficient implementation. The larger, outer shells have most of the mass, but tap very little power, and perform very little computation compared to the inner shells (though you get better computation-per-unit-power due to reduced thermal noise).

For best mass efficiency, you'd use a single Dyson sphere that was as small as possible will still having a cool enough outer surface to have a reasonable Carnot efficiency (assuming you're running a heat engine; this is limited by the maximum temperature of your inner surface material and your working fluid, and gives you something with a radius anywhere from Mercury's orbit to Venus's, depending on what your efficiency threshold is).

A photovoltaic Matrioshka brain could have better efficiencies, though its computation efficiency might be lower. This is governed by the requirement that your working voltage be at least 4kT in order to be reasonably noise-resistant (if you're using electrical computing elements).

Actually, I should probably just add all of this with a bit more detail to the article later.

[Chris]


 * Actually, most of the mass goes into the radiators and cooling fluid (not the energy collectors, computational units or communications interfaces). As the design for the MBrain calls for probably 5-10 layers constructed using all of the available materials in orbits ranging from within Mercury to outside Pluto the factors Chris points out *are* taken into account. The multi-layer design is optimized by function depending upon each layer's operating temperature (energy density) and materials availability.  This probably means that most of the computation is done in the inner layers while most of the information storage is done in the outer layers (presumably using caching methodologies to minimize information retreival delays).  The architecture evolves over time (in the early years) as the planets are disassembled and various elements move moved to orbits where they are most useful.  For example iron could be used as a liquid coolant for the most high temperature layers, as radiator material (esp. when combined with oxygen) for the intermediate temperature layers and as an information storage material (using its magnetic properties?) in the coolest outermost layers.  Getting the optimal location for all of the available material depends upon the material designs of the specific layers and the computing architectures which are in turn determined by what the MBrain wants to "think" about and how it goes about doing so.


 * I suspect during the early evolution of the MBrain there is a movement of the most useful elements (C,N,O,Al) into the inner solar system and some of the heavier elements (Fe,Co,Ti) to the outer solar system. The picture gets quite complex as while W is a very high temperature material it isn't very abundant.  Many carbides (SiC), nitrides (Si2N3), and oxides (Al2O3) have high melting points and could be relatively abundant if you move the outer solar system material inward.  It is a reasonably complex problem once you take solar system element abundances and the physical properties of various elements and compounds into account (which I have done).  Combine that with the relatively unlimited nature of computing architectures and it becomes horrendously complex.


 * The rate of evolution changes significantly after one has disassembled all of the planets because then one has to start the disassembly of the Sun itself. That takes a long time due to the massive energy requirements of lifting material out of the Sun's huge gravity well.  One wants to separate out the heavier elements and probably put the H & He back into the Sun.  This not only lengthens the lifetime of the sun (by reducing the fusion rate) but gives you the heavier elements for construction purposes without having to breed them (which is an expensive and somewhat messy process).  Decreasing the diameter & temperature of the Sun also allows you to move the computational nodes inward within the solar system thus decreasing the inter-computational node information transmission time.


 * Please do not quote any of this in the Wiki entry directly as it would tend to make the top level entry quite long (which is probably undesirable) and the information is semi-speculative (i.e. not really "verifiable") on my part. Thanks


 * If any wiki authors would like to contact me directly with questions, they may do so at Robert.Brad__REMOVE-THIS__bury at gmail.what-you-would-expect.


 * [Robert]

Is there any way at all to guestimate a resonably plausable number for the computational capacity of one of these. I suppose a crude way would be to assume the entire output of the sun being used as efficiently as possible for computation and then multiplying that number by a an efficiency factor of anywhere from 99.99% to 0.000001%


 * There may be a hand-wavy upper limit:   5.0 * 1050 instructions per  second kg, mass available, 450 Earth masses (1 earth mass = 6 * 10 24 kg) 1.35 x 10 78 ops per second. Compare with some hand-wavy figures for all previou s electronic calculations ever - proxied by an up-scaling of what we have now, suppose we have 10 billion computers all running at 10 Ghz (1 op per cycle), and they have all been around 10 years that's 10^20* 10*=365.25* 86400≃3.1* 10 28 operations ever. Rich Farmbrough, 09:20, 1 March 2011 (UTC).

There was a small error in the description of the physics in the article. To be in equilibrium, each sphere must radiate exactly as much energy as it receives, thus it cannot give off "less heat". It may radiate at a lower temperature. The total heat energy would be the radiation temperature summed over the surface area. For there to be a temperature differential, a given layer must have some non-trivial thickness. Alternately, it could use something besides temperature difference to drive the computation (such as photovoltaics).

Frothga (talk) 14:48, 26 August 2020 (UTC)

Improper Links
It looks like I goofed! Sorry. I "updated" the link to the Matrioska Brain "homepage" to point to the only working copy of the page I could find of the material on the Web, and didn't update the description of the link. My severe bad - as this implied the site belonged to Robert Bradbury when it did not. The page's original author has objected, so I've changed the URL to the orginal URL, even though this url still is not functional.

I will check occasionally, but if the "main" page doesn't go back up within the next couple of days, I'll just take the link out rather than either point to a resource the author does not wish to be associated with or leave a dead link in the article.

Beowulf314159 18:58, 21 January 2006 (UTC)

Further Link Updates
Due to ISPs now blocking some ports it may take some time before the original Matrioshka Brain Home Page URL can be fully restored. In the meantime the URL with an alternate port should work http://www.aeiveos.com:8080/~bradbury/MatrioshkaBrains/index.html

Robert


 * Thanks, I've updated the main article with the new link - Beowulf314159 12:51, 25 January 2006 (UTC)

A Name Correction: *Ray* Bradbury
This article says, "The term Matrioshka Brain was invented by Robert Bradbury...". Do you really mean Ray Bradbury? If so, please consider correcting it. I'd also like to see a reference to the article or story in which he coined the term.

Thanks,

Roy Beatty —The preceding unsigned comment was added by Rrbeatty (talk • contribs).

Look Again
Did you miss Mr. Bradbury's fairly lengthy post on this discussion page? Or did you just not read the signature? He is a distinct entity from Ray Bradbury.

209.115.173.21 06:58, 14 December 2006 (UTC)

This is Robert, and I am not going to bother with the Wikipeida formatting requirements. It is my current understanding, given the Bradbury Memorial, and my father (Rudolph Bradbury)'s pursuit of the family geneology that I am Norris E Bradbury's 5th cousin twice removed and Raymond Douglas Bradbury's 6th cousin twice removed. We are likely related but not one in the same. —Preceding unsigned comment added by RobertBradbury (talk • contribs) 17:13, 2 November 2007 (UTC)

Possible References
Re: Reference requirement. If one looks at the Matrioshka Brain Home Page (http://www.aeiveos.com:8080/~bradbury/MatrioshkaBrains/index.html) you will find there a list of references. The "Further Information" section cites a number of background papers, most of which are extensively referenced and the "Papers & Posters" section contains a list of papers/posters which have been reviewed in public forums. In approximately a decade of promoting the ideas I have never had anyone claim they are "impossible". The worst criticism I have received thus far was the refusal of prominent astrophysicists involved in gravitational microlensing observations to even consider the possibility of Matrioshka Brains explaining some of their observations. (If they haven't seen one, which is currently very *hard* with respect to Matrioshka Brains and Jupiter Brains, then they refuse to consider them (though they will consider *dark* matter!))  Of a more academic nature are the "Life at the Limits of Physical Laws" publications (they are in the OSETI III conference proceedings) and Milan Cirkovic's paper with my minor contributions, published in the peer reviewed New Astronomy Journal. In addition, my "Under Construction" chapter in Year Million, was subject to editorial review. While fictional in nature, it describes in detail a plausible construction path for a Matrioshka Brain in our solar system. There are several other chapters in that book which also discuss Matrioshka Brains. One may also want to review publications by Milan Cirkovic at ArXiv.org, several of which are about the Fermi Paradox and/or SETI, which in part were due to Milan's detailed exploration of Matrioshka Brains and Jupiter Brains and their possible existence. Milan is a hard core astrophysicist as can be concluded by reviewing his publication list on ArXiv.org.

Robert (talk) 12:18, 17 May 2009 (UTC)

Science Fiction?
I wonder - should this article not be placed in the context of Science Fiction? The concept is something purely fictional, right? In the article it sounds a bit like this is a realistic if hypothetical possibility. — Preceding unsigned comment added by 91.39.111.98 (talk) 22:13, 20 November 2011 (UTC)

We need a Wikipedia article on this Robert Bradbury
I just deleted a link in the article that indicated that the Robert Bradbury in question was the movie director that died in 1949 after directing many low-budget Westerns; he directed John Wayne as a singing cowboy in the 1920's, and made his last film just before the second world war. I doubt that he had much to say about computer architecture.

I would be glad to write an article about the Robert Bradbury who originated the concept of Matroishka brains, but I cannot find any material on the internet other than that written by Mr. Bradbury about the concept of Matroishka brains...nothing concerning who he is, his credentials, etc.

Any help from anyone who knows this person, or from Mr. Bradbury himself, would be appreciated. Ormewood (talk) 15:16, 27 July 2014 (UTC)


 * Help from Mr. Robert J. Bradbury would be most interesting if delivered personally, since he died 2.5 years before you posted that. His dates are 1956-2011; some info on him can be found in the obituary link I give below. Schissel | Sound the Note! 03:25, 19 April 2017 (UTC)

Citation Really Needed?
Since this page describes a purely hypothetical structure (it even says so in the first sentence), do the "citation needed" tags actually make sense? Especially, this one:


 * The ideal mechanism for extracting usable energy as it passes "through" a shell or component, the number of shells (or orbital levels) that could be supported in such a manner, the ideal size of the shells to be constructed, and other details, are all issues of speculation.[citation needed]

Does the fact that details of a hypothetical structure are "issues of speculation" really require a citation?

Tom (talk) 18:31, 22 October 2015 (UTC)
 * Yes, required. Wikipedia describes speculations of respectable author, not of every kook. - üser:Altenmann >t 05:52, 23 October 2015 (UTC)

That's pretty weird. "Hey you know this thing we already told you is hypothetical? We need citations to say that it's also only speculative. With no citations, this hypothetical thing might well exist" Tom (talk) 20:28, 23 October 2015 (UTC)
 * Did you read what I wrote? The "hypothetical" thing has an author: the author of the hypothesis. Once the  hypothesis is set, its consequences are either issues of logical  derivation or of speculation. And we need a reference which writes how the mechanism in question is to operate: will it be a pure guesswork (speculation) or we there are logically concluded possibilities. Without citation, either way it will be an opinion of a wikipedian, i.e., wikipedian's original research inadmissible in wikipedia.   - üser:Altenmann >t 00:46, 25 October 2015 (UTC)

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Bradbury
Apparently Robert J. Bradbury was born 1956 and died 2011 (https://groups.google.com/d/topic/alt.obituaries/CYtg9ajaphw ) (so of course not to be confused with filmmaker Robert N. Bradbury.) Schissel | Sound the Note! 03:24, 19 April 2017 (UTC)

Capitalization question
Should it be "Matrioshka brain" or "matrioshka brain"? -- Ahiijny (talk) 21:09, 15 March 2019 (UTC)

The word comes from Matryoshka, which is a proper name and is capitalized when discussing the dolls. Matrioshka is the spelling that Bradbury used in his paper, but it still stands as a proper name being used as an adjective, so it gets capitalization. Note that Bradbury capitalized all uses of it in the paper... but Bradbury also capitalized Brain in all uses, but I'm not willing to carry that through into common usage. AristosM (talk) 19:22, 25 March 2020 (UTC)
 * It comes from the doll type "matryoshka", which is of course not a proper name and thus not capitalized. — Mikhail Ryazanov (talk) 19:31, 17 February 2022 (UTC)

Would not work as intended
This concept would not really work. While it is true that it would be able to use up all energy from the star in the center, at the same time it doesn't make sense to have more than one Dyson Shpere in a Matryoshka configuration. For energy to be usable, you not just need an energy source. You also need an energy sink. In a single Dyson Sphere this is obviously perfectly fulfilled, as there is a star in the center and cold space around it. But with another sphere around it, the one inside is insulated from the cold space outside. So there ist less difference between energy source and energy sink, which means less usable energy. So it would not work as efficient, or wouldn't work at all after a while, when the space between the two spheres slowly heats up to the temperature within in the first sphere. This applies even more to a configuration with many nested Dyson Spheres. It acually is a method to reduce the usable energy difference for each sphere, making all spheres overall less efficient. Apart from the technological stupidity, this is a perfect example for Zeerust ("Zeerust: The particular kind of datedness which afflicts things that were originally designed to look futuristic." — The Meaning of Liff). Computers don't need heat. They need to be cooled! Also Computers don't work better when they are gigantic. The smaller a computer is, the better! Imagine how slow a computer would work in the scale of a Dyson Sphere, when each signal, even when travelling at the speed of light, still needs hours to get to the other side of the computer. --TeakHoken212.185.209.22 (talk) 13:57, 20 February 2024 (UTC)