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Is the Universe its own Largest Computer? 616

missingmatterboy writes: "If the universe is simply a giant calculating machine, how big is it? Seth Lloyd, who two years ago worked out the theoretical maximum possible power a laptop computer could posess, has now "estimated how much information the Universe can contain, and how many calculations it has performed since the Big Bang." His conclusion: you'd need about 10^90 bits, with something like 10^120 manipulations of those bits, to express the universe since time began."
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Is the Universe its own Largest Computer?

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  • by A nonymous Coward ( 7548 ) on Monday June 03, 2002 @12:54PM (#3632350)
    ...42!
  • wouldn't the calculation of it just add to the total number of calculations that the universe has made?
    • CPUs always do something, even if it's just look for something to do when "idle". Unless it uses the STOP / WAIT instruction to wait for something to wake it up. Maybe that's what the big bang was...
  • by LinuxDeckard ( 457253 ) <linuxdeckard AT netscape DOT net> on Monday June 03, 2002 @12:56PM (#3632375) Homepage
    I guess the fact we don't have weekly big-bangs indicates the universe doesn't run a certain OS out of Redmond :)
  • I only got 10^90 - 1 bits and 10^120 -2 calculations.
    Back to the drawing board..
  • by flewp ( 458359 ) on Monday June 03, 2002 @12:58PM (#3632394)
    If one plans on estimating the calculations (apparently changes) the universe has performed, how can you even make a guess when we still don't even know precisely how old the universe is, and how much matter there is?

    And also, why does everything have to be made into a computer of some sort? DNA, and now the whole universe?
    • by 2nd Post! ( 213333 ) <gundbear.pacbell@net> on Monday June 03, 2002 @01:05PM (#3632474) Homepage
      As far as I can recall, one of the basic premises of entropy and information theory is that *everything* can be expressed in bits.

      If everything can be expressed in bits, then everything is computable.

      A stupid question is whether the universe is a determinstic Turing machine or not, or whether it is by very nature indeterministic :P

      It's not that something has to be made into a computer so much as redefining one's perspective of what a computer is to accomodate the realities of the universe; that DNA is a storage mechanism, with RNA and DNA replication and protein synthesis being complex computation processes. Or that the universe is really expressible as a bunch of states (read his article, and you'll see that), and as such the traversal from state to state is no more complex than following a state diagram in a really big state machine...

      Which is just a computer, doncha know?
    • by geojaz ( 11691 )
      And also, why does everything have to be made into a computer of some sort? DNA, and now the whole universe?

      Simply, humans are simple and by comparing phenomena to computers or whatever it makes it a little easier for us to comprehend. Look at Wolfram's "new" book [amazon.com].
      The real question is at what point does the model become the real thing...
    • by aralin ( 107264 ) on Monday June 03, 2002 @01:11PM (#3632536)

      And also, why does everything have to be made into a computer of some sort?

      Maybe because its so much easier to think about God as a fellow programmer?

    • And now we have the two magical exponents we've been waiting so long to discover. Just THINK of the uses we can put this to! Please, please think of some, because I sure as hell can't.

      Ryan
    • "why does everything have to be made into a computer of some sort? DNA, and now the whole universe?"

      Well, that's a complicated question. Computation is the manipulation and/or transformation of symbolic information. Since this is basically how human beings interact with the universe, it makes sense that we would try to understand it in that context. It would make little sense for us to measure our universe in terms of the correctness of its shape, since we don't have a point of reference for that.

      I'm of the opinion that this is not terribly interesting because there are probably much larger symbols involved in the universe's "execution". I'm not sure I'm in the "10 lines of code" camp, but certainly it is attractive to presume that there are formulae -- which are simpler than the universe as a whole and which can take less starting information than the state of the entire universe -- that describe the iteration of the universe. We shall see....
    • And also, why does everything have to be made into a computer of some sort?

      Why does everyone think that just because it doesn't come in a beige box that it isn't a computer. Why just look at me for example.... No. Wait. I'm kinda beige. Bad example.
    • by texchanchan ( 471739 ) <`ccrowley' `at' `gmail.com'> on Monday June 03, 2002 @02:09PM (#3633034)
      Re,
      "...why does everything have to be made into a computer of some sort?"

      Because computers are the hot new technology. In the 1700s, say 250 years ago, things were described in terms of air pumps. Even thought was described using a model of a lot of little air pumps in your brain. That was because they were new, hot technology.
  • It's not (Score:2, Funny)

    by Bake ( 2609 )
    The Universe is not the Universe's largest calculator. That title belongs to Earth. Everybody knows that who has read the Hitchhiker's Guide.
  • His conclusion: you'd need about 10^90 bits, with something like 10^120 manipulations of those bits
    And as everyone knows the answer is 42.
  • by tps12 ( 105590 ) on Monday June 03, 2002 @12:59PM (#3632408) Homepage Journal
    Like many of the other socially handicapped computer geeks here on slashdork, I was excited about this whole concept. The Universe as a giant computer is an extremely cool idea, IMO.

    But then I reconsidered. After all, if the whole galactical starscape that spreads before us as we gaze into the night sky is in the end a really gigantor computer, then, well, the Athlon by my desk starts to look pretty puny.

    All of a sudden, when faced with the sheer computatorial power represented by the glorious heavens above, things like "operating system," "information superhighway," and "porn" start to stop meaning so much.

    In a world where we're all part of a gigantical computer, who gives a shooting starfuck about Linux?
  • Well... (Score:4, Funny)

    by Have Blue ( 616 ) on Monday June 03, 2002 @01:00PM (#3632411) Homepage
    ...if the universe has performed 10^120 operations and it's about 20 billion years old, it's running at about 4*10^90 gigahertz. Imagine a Beowulf cluster of those!
  • by cybrpnk2 ( 579066 ) on Monday June 03, 2002 @01:00PM (#3632415) Homepage
    The article implies there hasn't been enough time for each bit/particle in the universe to have been "flipped" more than once, which further implies that the universe is NOT a computer. However, the number of particles mentioned is that in out 3D/4D (space / spacetime) universe. With superstring theory postulating extra dimensions up to 10 or 11 all "curled up" out of our sight, maybe this is where extra particles/bits are located to support the universe as a computer?
  • I want a beowulf cluster of those.
  • by Liora ( 565268 )
    that information was already obsolete at press-time, given continual universal expansion.
  • In refence to using "pings" to perform calculations, and using the game of life to generate prime numbers...

    it would be neat if we could use the universe as a copmuter to play a huge interactive game like The Sims.

    Maybe one day.
  • by Synn ( 6288 )
    Wonder if I can file a patent on it and make everyone pay me licensing fees for existing.
  • by PissingInTheWind ( 573929 ) on Monday June 03, 2002 @01:03PM (#3632449)
    If I was God, I think I would have only written a few Lisp macros to build it all.

    That would explain too why evolution takes millions of year... though it would explain too why it simply works.

  • To simulate the Universe in every detail since time began, the computer would have to have [10^90] bits - binary digits, or devices capable of storing a 1 or a 0 - and it would have to perform [10^120] manipulations of those bits. Unfortunately there are probably only around [10^80] elementary particles in the Universe.

    So... there are only 10^10 bits of unique information to be bookkept for every elementary particle? I find this intuitively inadequte. The precision needed just for locating the particle in the vastness of the universe is immense. Not to mention derivatives of this value wrt time...

    Of course, we could see a lot more improvement if we used quantum computing.

    Oh, wait - that's already been done! We're part of it.

    • So... there are only 10^10 bits of unique information to be bookkept for every elementary particle? I find this intuitively inadequte.

      I think there are two points to this:

      * it is a reasonable, probably correct, conclusion to draw that a classical, finite state binary computer could not be constructed within the universe that would be capable of running the universe on itself ... at least not within the lifespan of the universe itself AND with the computational resources of the universe itself (remove either of those two constraints and it might well be possible ... remember than any simple turing-complete machine can emulate any other turing complete machine of arbitrary complexity and power, provided your willing to trade off time against computational capacity). Since the question is whether or not we can do this within the confines of this universe, those limitations are, at least as long as we don't know how to tunnel out of this universe or access whatever underlying structure might contain it, very reasonable.
      * your intuition is correct as far as it goes, but you are not accounting for changing states encoded in the calculation (but not stored to media). Storage requirements would likely be much greater if you wanted to take a snapshot every, say, planck-time unit (~10-64 sec). But if your goal is simulation, not archival, the numbers given might be adequate, assuming their underlying assumptions are correct.

      Of course, we could see a lot more improvement if we used quantum computing.

      I think you touch on something interesting here (in addition to the obvious fact that we are, in fact, embedded in a quantum universe/computer) ... with quantum computing it may become possible to emulate the universe without using so much storage and/or computational power, depending on what sorts of shortcuts quantum algorithms may allow for. Intuition tells me that won't fly, but intuition is a dangerous thing to use when dealing with QM, which at its heart is quite alien to our "common-sense" yet nevertheless demonstrably true. It is possible that the way eigenstates collapse in nature is not the most efficient way they can collapse, particularly when looked at from a computational perspective. Fun speculation for a good SF story if nothing else. :-)
  • Moore or less... (Score:5, Interesting)

    by jolshefsky ( 560014 ) on Monday June 03, 2002 @01:07PM (#3632496) Homepage
    According to Moore's law, the typical desktop computer should be able to simulate the universe in less than 600 years.

    (18 months per double; 10^120 =~= 2^399; 1.5 years * 399 = 598.5 years)

    • by gosand ( 234100 ) on Monday June 03, 2002 @02:19PM (#3633118)
      According to Moore's law, the typical desktop computer should be able to simulate the universe in less than 600 years. (18 months per double; 10^120 =~= 2^399; 1.5 years * 399 = 598.5 years)

      Hmm, wonder what it will be able to calculate in 601 years...

      Actually, in 600 years, there will 600 more years worth of calculations to do. Including the simulation in question. Ouch, that hurt.

      • No problem (Score:3, Insightful)

        by Dada ( 31909 )
        Just wait for the next generation of computers then: they will be able to simulate the whole history of the universe, plus those 600 years, plus another 13 *billion* years more :).
  • by eaeolian ( 560708 ) on Monday June 03, 2002 @01:07PM (#3632499)
    ...as ultimately flawed as any other analogy. The universe isn't a computer, it's a universe. Analogies like this can be useful in understanding some aspects of the universe, but I doubt it's a "be all, end all" view of things.

    Then again, I'm hardly a cosmologist, so YMMV.

    Mike

    • I beg to differ (Score:3, Insightful)

      by SIGFPE ( 97527 )

      Analogies like this

      It's not an analogy. It's a perspective. From a certain point of view the universe might look exactly like a computer. If it does then it might as well be a computer because you can treat it exactly like one. This doesn't preclude the possibility that there might be other points of view too.


      There is, of course, the possibility that it's not a valid point of view. But that needs more arguing than simply "the universe isn't a computer".

  • I wish that article had given more detail. It seems to me that things like motion and time would not be able to accuratly be coverted into a digital representation and still be accurate enough to represent the entire universe. Wouldn't you have to calculate it with a vector based system? If he wasn't using a vector system then that number 10^90 or whatever it was would probably be significantly smaller.

    So if we are currently a part of a giant algorithym, if we ever actually create a computer capable of simulating the whole thing, would the first person to do it be able to patent it? Also, in order to figure out what happened at creation you would have to reverse engenier the whole thing. Wouldn't that be a DCMA violation?

  • His conclusion: you'd need about 10^90 bits, with something like 10^120 manipulations of those bits, to express the universe since time began.
    OK, that gives us some idea as to just how much RAM V'GER had.
  • How many FPS can you get on this computer while playing Counter Strike or Doom 3?
  • 256 bits (Score:3, Insightful)

    by yamla ( 136560 ) <chris@@@hypocrite...org> on Monday June 03, 2002 @01:14PM (#3632570)
    I guess 256 bits of encryption (where each possible combination results in a strong key) will never be brute-forced, then.
  • But how fast is it?

    ...with something like 10^120 manipulations of those bits...

    Let's see, the universe is about 15 billion years old. 10^120 floating point operations divided by..mumble..mumble..mumble.. That comes out as roughly 2 * 10^101 flops. If the graphics resolution is about... PI multiplied by 15 billion light years by..mumble..mumble..OH WAIT, it's in 3D..mumble..mumble..HEUREKA!

    The graphics performance comes out as EXACTLY 42 FPS.

    Hmm. Not too impressive, really.
  • by E1ven ( 50485 ) <e1ven@e1ven . c om> on Monday June 03, 2002 @01:16PM (#3632593) Homepage
    With calculating power like that, you /might/ be able to run Doom III at the highest settigs ;)
  • by crovira ( 10242 ) on Monday June 03, 2002 @01:17PM (#3632597) Homepage
    According to some theories, the universe is an 11 dimensional finite state machine with a cycle time of 1x10-63second ... Plankt time.

    It would seem to be guided by an irrational number calculation something very much like Mandlebrot's x=1/xi but in 11 dimensions.

    A VERY simple calculation with chaotic consequences.
  • That's like saying that a physicist is an atom's way of finding out about atoms, or that mathematics is the language of the universe. Physics and Mathematics are only approximations used to build models which explain most aspects of the way our world works. We're getting better, but they're our language, not nature's.

    Unless, of course, it was all instigated by one intelligent being; Possible but unlikely.

  • sometimes it seems like it must be a beta relase
  • by iaamoac ( 206206 ) on Monday June 03, 2002 @01:22PM (#3632644)
    1. ...the expansion of the universe is similar to never de-allocating memory?

    2. ...the rapid expansion phase at the beginning was someone trying to overclock the universe?

    3. ...the big crunch comes when MS figures out how to write software for the univsersal computer?

    4. ... the CPU manufacturers are right around the corner to making a computer more powerful than universe.

    5. ...all the weird stuff at the quantum scale is caused by dereferencing a NULL pointer.

    Iaamoac

  • One idea that's been floating around in my head for years is that someone should get a supercomputer (or a big Beowulf cluster) and try to run their own sim-universe.

    Of course, it'd have to have simplified rules (we don't yet know all the rules to out own universe), and it'd probably have to be with a smaller number of bits (quarks?). But I wonder what kind of results we could get. It'd probably take a bit of tweaking to get the physical laws set up right so that stars form and function, or maybe even planets form (at least gas giants).

    Is this project too big to even think about right now?
  • "googol" = 10^100
    universe = 10^90 bits
    Therefore, the entire universe can be found at Google [google.com].

    d, disappointed that "googol" is not spelled "google".

    p.s. the word has now lost all meaning to me. google google google. nothing.

  • So since i am part and even this message is part of its computations it doesnt really matter what i do, maybe i should buy a gun and kill some people..

    Damn people who say crap like this should be shot, cause they only point out how non important our lives really are.

    Hope these words get used correct in the computation and that they are not some syntax errors.
  • The universe could have been created by a controlled explosion where a matter/antimatter universe pair were created simultaniously, perhaps with a controlled beginning. Black holes could be used as output devices, spitting out vast streams of data that a higher intellegence could be collecting and analyzing.

    But what kind of program? Perhaps its something as trivial as a complex "Game of Life" scenario. Perhaps the universe itself is trivial in the grand scheme of things. Perhaps it represents a single CPU in a vast SMP system of trillions upon Trillions of other processors. Imagine the framerate on THAT monster. :)

    -Restil
  • The ambient temperature of the universe from background radiation is 2.7 degrees Kelvin. Find yourself a handy dandy superfluid helium heat sink that fits nicely around the galactic core... any high school kid can figure out how to do that, and you can lower that to 1.7 degrees Kelvin! I haven't tried it yet at home, but I bet you could pull another 12^100 manipulations out of it over the next trillion years!

    I hear that Intel finally plans to release their new line of Higgs Boson based universe macroprocessors next year, and that will of course leave all of these benchmarks in the dust, but I'm sure some hobbyist will find a way to overclock those universes as well. AMD has tried to do some tesseract-based preemptive processing, but the Matrix System Agents doesn't think that extra juice is needed to continue fooling the human batteries that the universe is just one big number crunch, so they may lose market share. ;-P
  • Isn't the Universe an analog sytstem?

    It's nice that he decided that changes in quantum state are equivilent to 'bits', the changes in the universe also happen without a quantum state change. He also doesn't acount for the movement of sub-atomic particles, or even the number of quantum states of each paricle. These 'bits' in his formula could not be binary for sure.

    Hence it seems to me his equation is flawed in attempting to express the universe as a digital computer. Perhaps he should re-state the problem and look at the universe as an analog computer like it really is.

  • Tonight at 9:00 PM (Eastern Time) Discovery Channel (Channel 42) features a one hour program on the origins of the Universe.

    In this feature, of which 21 minutes is devoted to NCSA produced visualizations, which includes the spectacular rendition of a flight from earth to the massive black hole on the center of our galaxy.

    21 minutes of NCSA rendered graphics...yummm..

    So dont miss it, even if you werent a space geek. Being a graphics fan would do fine.
  • worked out the theoretical maximum possible power a laptop computer could posess

    I didn't read about this, but it seems that unless he absolutely and rigidly defined what a laptop is (which I don't think is necessarily definable considering what a "portable" from 30 years ago was and therefore what it might mean in another 30 years) he is going to feel very silly and very wrong in a short while.
  • There are numerous researchers who have said that the multiverse (of which our universe is of course just a tiny part) has a total information content of essentially zero.

    Those of you with too much time on your hands may enjoy Schmidhuber's 1996 paper, A Computer Scientist's View of Life, the Universe, and Everything [idsia.ch].

    And check out the Everything List archives [escribe.com] too.

  • --| THE TRANSITION FROM THE EMPIRICAL TO THE IDEAL |---

    We take hold of a warm object, for example. The scientist will tell us: What you are calling the heat or warmth is the effect on your own nerves. Objectively, there is the movement of molecules and atoms. These you can study, after the laws of mechanics. So then they study the laws of mechanics, of atoms and molecules; indeed, for a long time they imagined that by so doing they would at last contrive to explain all the phenomena of Nature. Today, of course, this hope is rather shaken. But even if we do press forward to the atom with our thinking, even then we shall have to ask - and seek the answer by experiment - How are the forces in the atom? How does the mass reveal itself in its effects, - how does it work? And if you put this question, you must ask again: How will you recognize it? You can only recognize the mass by its effects.

    The customary way is to recognize the smallest unit bearer of mechanical force by its effect, in answering this question: If such a particle brings another minute particle - say, a minute particle of matter weighing one gramme - into movement, there must he some force proceeding from the matter in the one, which brings the other into movement. If then the given mass brings the other mass, weighing one gramme, into movement in such a way that the latter goes a centimetre a second faster in each successive second, the former mass will have exerted a certain force. This force we are accustomed to regard as a kind of universal unit. If we are then able to say of some force that it is so many times greater than the force needed to make a gramme go a centimetre a second quicker every second, we know the ratio between the force in question and the chosen universal unit. If we express it as a weight, it is 0.001019 grammes' weight. Indeed, to express what this kind of force involves, we must have recourse to the balance - the weighing-machine. The unit force is equivalent to the downward thrust that comes into play when 0.001019 grammes are being weighed. So then I have to express myself in terms of something very outwardly real if I want to approach what is called ÒmassÓ in this Universe. Howsoever I may think it out, I can only express the concept ÒmassÓ by introducing what I get to know in quite external ways, namely a weight. In the last resort, it is by a weight that I express the mass, and even if I then go on to atomize it, I still express it by a weight.

    I have reminded you of all this, in order clearly to describe the point at which we pass, from what can still be determined Òa prioriÓ, into the realm of real Nature. We need to be very clear on this point. The truths of arithmetic, geometry and kinematics, - these we undoubtedly determine apart from external Nature. But we must also be clear, to what extent these truths are applicable to that which meets us, in effect, from quite another side - and, to begin with, in mechanics. Not till we get to mechanics, have we the content of what we call Òphenomenon of NatureÓ.

    All this was clear to Goethe. Only where we pass on from kinematics to mechanics can we begin to speak at all of natural phenomena. Aware as he was of this, he knew what is the only possible relation of Mathematics to Natural Science, though Mathematics be ever so idolized even for this domain of knowledge.

    To bring this home, I will adduce one more example. Even as we may think of the unit element, for the effects of Force in Nature, as a minute atom-like body which would be able to impart an acceleration of a centimetre per second per second to a gramme-weight, so too with every manifestation of Force, we shall be able to say that the force proceeds from one direction and works towards another. Thus we may well grow accustomed - for all the workings of Nature - always to look for the points from which the forces proceed. Precisely this has grown habitual, nay dominant, in Science. Indeed in many instances we really find it so. There are whole fields of phenomena which we can thus refer to the points from which the forces, dominating the phenomena, proceed. We therefore call such forces Òcentric forcesÓ, inasmuch as they always issue from point-centres. It is indeed right to think of centric forces wherever we can find so many single points from which quite definite forces, dominating a given field of phenomena, proceed. Now need the forces always come into play. It may well be that the point-centre in question only bears in it the possibility, the potentiality as it were, for such a play of forces to arise, whereas the forces do not actually come into play until the requisite conditions are fulfilled in the surrounding sphere. We shall have instances of this during the next few days. It is as though forces were concentrated at the points in question, - forces however that are not yet in action. Only when we bring about the necessary conditions, will they call forth actual phenomena in their surroundings. Yet we must recognize that in such point or space forces are concentrated, able potentially to work on their environment.

    This in effect is what we always look for, when speaking of the World in terms of Physics. All physical research amounts to this: we follow up the centric forces to their centres; we try to find the points from which effects can issue, For this kind of effect in Nature, we ate obliged to assume that there are centres, charged as it were with possibilities of action in certain directions. And we have sundry means of measuring these possibilities of action; we can express in stated measures, how strongly such a point or centre has the potentiality of working. Speaking in general terms, we call the measure of a force thus centred and concentrated a ÒpotentialÓ or Òpotential forceÓ. In studying these effects of Nature we then have to trace the potentials of the centric forces, - so we may formulate it. We look for centres which we then investigate as sources of potential forces.

    Such, in effect, is the line taken by that school of Science which is at pains to express everything in mechanical terms. It looks for centric forces and their potentials. In this respect our need will be to take one essential step - out into actual Nature - whereby we shall grow fully conscious of the fact: You cannot possibly understand any phenomenon in which Life plays a part if you restrict yourself to this method, looking only for the potentials of centric forces. Say you were studying the play of forces in an animal or vegetable embryo or germ-cell; with this method you would never find your way. No doubt it seems an ultimate ideal to the Science of today, to understand even organic phenomena in terms of potentials, of centric forces of some kind. It will be the dawn of a new world-conception in this realm when it is recognized that the thing cannot be done in this way, Phenomena in which Life is working can never be understood in terms of centric forces. Why, in effect, - why not? Diagrammatically, let us here imagine that we are setting out to study transient, living phenomena of Nature in terms of Physics. We look for centres, - to study the potential effects that may go out from such centres. Suppose we find the effect. If I now calculate the potentials, say for the three points a, b and c, I find that a will work thus and thus on A, B and C, or c on A', B' and C'; and so on. I should thus get a notion of how the integral effects will be, in a certain sphere, subject to the potentials of such and such centric forces. Yet in this way I could never explain any process involving Life. In effect, the forces that are essential to a living thing have no potential; they are not centric forces. If at a given point d you tried to trace the physical effects due to the influences of a, b and c, you would indeed be referring to the effects to centric forces, and you could do so. But if you want to study the effects of Life you can never do this. For these effects, there are no centres such as a or b or c. Here you will only take the right direction with your thinking when you speak thus: Say that at d there is something alive. I look for the forces to which the life is subject. I shall not find them in a, nor in b, nor in c, nor when I go still farther out. I only find them when as it were I go to the very ends of the world - and, what is more, to the entire circumference at once. Taking my start from d, I should have to go to the outermost ends of the Universe and imagine forces to the working inward from the spherical circumference from all sides, forces which in their interplay unite in d. It is the very opposite of the centric forces with their potentials. How to calculate a potential for what works inward from all sides, from the infinitudes of space? In the attempt, I should have to dismember the forces; one total force would have to be divided into ever smaller portions. Then I should get nearer and nearer the edge of the World: - the force would be completely sundered, and so would all my calculation. Here in effect it is not centric forces; it is cosmic, universal forces that are at work. Here, calculation ceases.

    Once more, you have the leap - the leap, this time, from that in Nature which is not alive to that which is. In the investigation of Nature we shall only find our way aright if we know what the leap is from Kinematics to Mechanics, and again what the leap is from external, inorganic Nature into those realms that are no longer accessible to calculation, - where every attempted calculation breaks asunder and every potential is dissolved away. This second leap will take us from external inorganic Nature into living Nature, and we must realize that calculation ceases where we want to understand what is alive.

    (Rudolf Steiner, The Light Course, Lecture 1)

    Light Course, Lecture 1, Rudolf Steiner [earthlink.net]

  • Warning: Do not read if you are not Zaphod Beeblebrox.

    Okay, 10 ^ 80 fundamental particles. That's a lot.

    Then, 10 ^ 90 bits, or 10 ^ 10 bits per particle.

    Those 10 ^ 10 bits each particle possesses, can express a meager 2 ^ 10 ^ 10 = 10 ^ 3 billion or so possible values (since 2 ^ 10 = 10 ^ 3). Let's assume that the universe is a cube, with a "resolution" of 10 ^ -24 meters (electrons don't really have a radius, but when you try to measure it all you can say is that it's less than 10 ^ -18 meters, a millionth of that seems safe.)

    So, 10 ^ 3 billion numbers can represent positions on three dimensional axese 10 ^ 1 billion "units" long - that's the cubed root.

    Even if our pixel is only 10 ^ -24 meters across, we only lose 24 (to meters) and 16 (to light years) decimal orders of magnitude, so that's describes a cube 10 ^ (1 billion - 40) light years on a side.

    Realizing that my overclocked, water cooled Duron, which I had thought was so l33t, is nothing compared to the infinite cosmos upon which it is only a tiny speck, I go insane, and start thinking about relativity.

    Okay, to say that events that occur at different points in space is actually meaningless. Relativistically nonsensical. It's may be a requirement at the quantum scale, or it may fuzz out somehow from the heizenberg uncertainty principle (which applies to time as well as space,) but anyway - with no real concept of simultaneity shared by different bits of the great computer, how does the universe get anything done? Maybe, the universal background radiation isn't just something we use as a clock, maybe it REALLY IS A CLOCK - a synchronizing pulse.
  • then everything looks like a nail.

    If the universe is a computer then everything must be a calculation. Funny I thought I was more than that.
  • Human Free Will (Score:3, Insightful)

    by rarose ( 36450 ) <rob@@@robamy...com> on Monday June 03, 2002 @01:45PM (#3632856)
    Nobody has mentioned yet this little nugget: If the universe is a computer then we are but small little threads of the Earth process. And we have no such thing as free will... just private member variables that we're not aware of.

  • Is there a version control system in place? I want check out a previous version and get my old girlfriend back...
  • Data compression (Score:3, Insightful)

    by Rorschach1 ( 174480 ) on Monday June 03, 2002 @01:46PM (#3632869) Homepage
    I've thought about this before, and came to the conclusion that if I ever build my own universe I'm going to need to use data compression of some sort, and kind of fudge the details. I mean, who cares exactly where an electron is, as long as it statistically behaves like it should?

    The scary thing is, the more I've learned about quantum mechanics, the more it looks like that's how the universe works.
    • if I ever build my own universe I'm going to need to use data compression of some sort, and kind of fudge the details. I mean, who cares exactly where an electron is, as long as it statistically behaves like it should?


      Exactly. And I wouldn't waste effort calculating the position of every single electron at every point in time either; I'd just wait until a measurement was taken on it and then compute where it should be. And depending on the formulas I used, this could confuse the simulated scientists in my universe, who would be wondering how electrons could pass through two slits simultaneously, but only when they weren't looking. Wait a minute...

  • by RyanFenton ( 230700 ) on Monday June 03, 2002 @01:47PM (#3632872)

    For instance, gravity seems to have a universal effect. It diminishes over distance, but ultimately never stops having an effect. Thus, for every movement, you'd first need to look at all elements of the "gravity map" to determine your precise gravity vector, then you'd need to update the "gravity map" with your movement. This would seem to have at least an N^2 effect. The universe doesn't seem at least to kludge on things like this.

    Many forces act like this, which would tend to make the exponent on the number of bit manipulations required blossom much faster than predicted. Take a look at raytracer graphic design to see how messy reality can be when you introduce more than a couple elements into a scene, much less of course a universe. If one is going for a true simulation of reality, at least force by force, particle by particle, I believe it's going to be more complex than this estimation.

    :^)

    Ryan Fenton
  • by dpbsmith ( 263124 ) on Monday June 03, 2002 @01:51PM (#3632898) Homepage
    1) Yeah, but it's an ANALOG computer. How passe!

    2) Except, it isn't even an analog computer, because there is no analogy involved; no abstractions, nothing representing anything else in a simpler, faster, cheaper or more convenient way.

    Remember the map of England in Lewis Carroll's "Sylvie and Bruno?" Well, I'm not sure I remember it, but, IIRC it was at a scale of one inch to the inch, so it was extremely accurate, but very annoying when unfolded and spread out.
  • by SiliconEntity ( 448450 ) on Monday June 03, 2002 @01:52PM (#3632904)
    A preprint is available online from the quantum physics archive [arxiv.org]. PS and PDF formats.

    BTW he is only talking about the observable universe in considering its computational capacity. For all we know the entire universe is infinite, but we can only see a finite bubble about 13 billion light years in radius. That's the part Lloyd is considering.

  • Hash functions (Score:3, Interesting)

    by XNormal ( 8617 ) on Monday June 03, 2002 @02:07PM (#3633020) Homepage
    10^90 is about 2^300 bits

    10^120 is about 2^400 operations

    Now, can anyone explain to me why anyone would need a cryptographic hash function with a 512 bit output? [nist.gov]

A man is known by the company he organizes. -- Ambrose Bierce

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