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Science

Time Doesn't Exist 375

Posted by Hemos
from the i-am-a-travellor-of-both-time-and-space dept.
Meshula writes "An interesting article suggesting that time is an illusion of perception has appeared at New Scientist. "...quantum mechanics supports it. In 1929, the British physicist Nevill Mott and Werner Heisenberg from Germany explained how alpha particles, emitted by radioactive nuclei, form straight tracks in cloud chambers. Mott pointed out that, quantum mechanically, the emitted alpha particle is a spherical wave which slowly leaks out of the nucleus. It is difficult to picture how it is that an outgoing spherical wave can produce a straight line," he argued. We think intuitively that it should ionise atoms at random throughout space. Mott noted that we think this way because we imagine that quantum processes take place in ordinary three-dimensional space. In fact, the possible configurations of the alpha particle and the particles in the detecting chamber must be regarded as the points of a hugely multidimensional configuration space, a miniature Platonia, with the position of the radioactive nucleus playing the role of Alpha. " It's worth a read. "
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Time Doesn't Exist

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  • "Down among the dancing quanta
    Everything exists at once"

    (from Transverse City)
  • so how do I go about ignoring this whole thing we call "time" and go back and get a '57 Chevy right off the production line?

    I mean, theory is great, don't get me wrong, but I want practical, like a car with damn big fins on it.


    Felix.
  • This actually came from Julian Barbour "The End of Time" on The Edge, Sept. 21. More there than in the article. http://www.edge.org/
  • I don't think this guy is a kook at all. From a cursory review of the sci.physics tree on deja.com he appears to be taken seriously. Are any of you actually physicists or merely opinionated. I seriously doubt that the majority of people calling Julian Barbour's reputation into question here are in any way qualified to make that judgement (not speaking specifically about the above AC just calling into question the reputation's of those who are casting aspersions). In the interest of full disclosure I am not a physicist and am in no way qualified to judge this man's ideas.
  • Wasn't that strange? I wondered if anyone else would notice that. I think he had to have imitated sagans vocal style on purpose. Or else sagan was an agent of the matrix.
  • I'm not sure if I understand exactly what you mean in your argument against the article, but:

    "One solution to this has been to say that the wave collapses in =this= universe, but that there are as many universes as possible states."

    Doesn't this statement match perfectly with the author's idea that our universe is just a certain state amongst many other states, given by a probability cloud? You seem to agree with him that there are many states, of which our percieved universe is only one. He is just saying these myriad states are given by a probability cloud, and that was we percieve as time in /your/ universe moving forward, is actually instantaneous recalculations of new states. These seem to be reconciled with each other, to NOT contradict each other.
  • Oh yeah?!

    3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 8... (101 decimals from memory)

    Geekier than thou! ;-P

    /Dervak

  • At some point it becomes impossible to think about physics questions without being struck by the philosophical implications. However in this particular case the question of whether time is "real" or merely an exercise in human perception has been a batted around for a long time.

    Think for a moment about a mechanical computer. One that perhaps even happens to be sentient. This computer works by a complex gear mechanism that is driven by being moved forward on a track.

    So as the black box moves forward along the track, the mechanical action drives a complex gear train that allows it to think. Since it thinks, it perceives itself, and it perceives itself to exist in a single dimension. It thinks that "right now" is the present, what it will think when it is a mile down the track as the future, and what it thought when it was a mile back as being in the past. Furthermore, a mechanical interlock prevents it from rolling backwards, or travelling back in time.

    An outside observer can tell that "time" is just an illusion of the machine's motion down the track. However, because of the inherent nature of the machine, to it time is an inescapable quality of existence.

    We are that machine. The track is the chemical reactions that take place in our brain and allows us to think. These chemical reactions are, thanks to thermodynamics and entropy, non-reversible. They only work as me move forward in time and that defines the nature of our existence.

    BTW: This was not my original idea, go read Bertrand Russell

    For the glib take on the above read Slaughterhouse Five by Kurt Vonnegut
  • I have held to this theory for quite some time now.. The only difference is that instead of saying time does not exist, I re-define time to fit the theory.. Length, Width, Height, Time... its not Rocket Science. hehehe... he said "time".. hehe.. My High School Physics teacher taught this theory..
  • It's beyond the realm of quantum mechanics to prove whether or not time exists. QM just assumes time is constant.
    With QM in its current state, we'll never be able to prove whether Julian's Theory is true, solely because of the initial assumption that QM makes. If QM assumes time is constant, how can it be used to show it doesn't exist?
    We know for a fact that time is NOT constant. Time is warped by such things as acceleration and gravity.
    This is the primary reason that Quantum Mechanics and Relativity are fundamentally incompatible theories. QM explains the probabilities that occur in the interactions between particle-waves, but it does not begin to explain what "time" is, or what "gravity" is! Relativity shows us that time and gravity are very connected. What we need here is *GASP* a Grand Unified Theory!
    So far, Superstring Theory is the closest thing yet, because it's compatible (so far) with both quantum physics and relativity.

    An excellent book on this subject is "The Elegant Universe" by Brian Green. You'll find that time does exist, as one of eleven dimensions, but the notion of space-time needs to be changed.

    On a more philosophical note... time MUST exist, in the same way that everything else "exists." It can be argued that space and time are merely a matter of perception, so that if something is perceived, that's all that's required for existence. As morpheus said, "How do you define 'real?'"

    Does it really change anything as far as we're concerned to prove that time doesn't exist? It's just a theory. Theories are just there to make sense of observed behavior. Superstring theory is one of those, although so far nobody's been able to come up with an experiment to test it. So right now, it just works... in theory. Or something.


  • Time is just another spacial dimension.. We already know (if we believe Einstein) that space can get warped pretty good by this kind of stuff (and gravity as well).
  • In fact, I just traveled 30 seconds into the future waiting for /. to respond.
  • Why would it have to start anywhere? So you can set your absolute time clock? If it exists at all, time is certainly relative.
  • In other words, your "many universes" still presuppose some absolute time, through will all universes travel in parallel. The author, from what I can tell is saying that, although there ARE an infinity of universes/states, they do not move in time "independently" of each other, but instead are just probabilities paths. There is nothing preventing THIS universe from becoming ANOTHER universe in your scheme, because according to him all universes/states are just probabilities, and one can /possibly/ move from any state to another.
  • Now does not exist. Now is simply something invented by humans, and the definition of now changes for every person. For example: "Right Now, humans use airplanes to fly" ....

    What the hell am i looking at? When does this happen in the movie?" "Now, your looking at now sir, everything that's happens now, is happening now." "What happened to then?" "We past then." "When?" "Just now." "We're at now, now" "Go back to then." "When?" "Now." "Now?" "Now." "We can't." "Why?" "We missed it." "When?" "Just now." "When will then be now?" "Soon." "How soon?"

    Ender

  • From which school did Einstein earn his PhD?

    Not saying this guy isn't a crackpot, I just think that giving him that label due to the lack of a PhD is taking the easy way out. :)
  • i completely believe you... but the point was, is that this isnt a "new" or "revolutionary" concept. You pointing out that it's been around longer than augustine, emphasizes this point.

    I find it amazing that people are still working on this, when it has been solved years ago...
  • For an "independent theoretical physicist", he sure doesn't know his math. "Dimension" is not necessarily synonymous with "number of coordinates". Triangle-land WOULD be 3-dimensional if it weren't for the "geometrical restrictions" that the author carelessly dismisses -- for example, (1, 2, 3) is not allowed in triangle-land.

    In fact, 2 vectors are all we need to represent all possible triangle configurations. If we have 2 vectors, x and y, then one side has length ||x||, one has length ||y||, and the 3rd side has length ||x-y||. Therefore, triangle land is spanned by the vectors (1,0) and (0,1), and thus it has dimension 2.

    Because of these pesky geometrical rules, the configuration space for a finite number of particles is not quite "hugely multidimensional", but is actually "3-dimensional".
  • I think you are missing the point of the article. It is trying to point out that time may not actually exist. That time, as we perceive it, is only a series of previous probabilies in this probability space called the Universe.

    The arrow flying towards you will continue on it's path because there's a high degree of probability that it will do so. There is a transition over the multidimentional space surrounding you and the arrow because of these probability waves.

    You perceive the differences (as he mentioned in the article) and say one happened in the past and the other in the present. You can even calculate with a high degree of accuracy (but not complete accuracy) that the arrow will strike a certain place on the target (hopefully now you). These perceived differences are time to you and me, cause we're 3-dimentional beings.

    Now, the whole argument with the Alpha particles was that Heisenberg thought that all probabilities occur at a quantum level. So there would be a spheroidal wave emitted from the atom. However, there isn't, because we only see on track in the cloud chamber (notice, this is at the atomic level...not something as big as an arrow). The solution was to view the emition of the alpha particle as occuring in n-dimensional space. We see our 3-dimensional view of it and, for us, it looks like a straight line cause that's what where the probability is greatest for us.

    As he mentioned, it would be nice to get rid of time altogether, since it seems to break down when we get back to Time 0 (the Big Bang). I'd like to see the math of this...
  • This reminds me of something I was thinking about awhile ago.
    I don't have the exact details as my physics book is not handy -- but I was studying the general relativity equations, and I decided to calculate what the distortion of time was for a particle of light in a vaccuum. Of coursre, light moves at the speed of light, c. So if you plug in c and solve the equation, you get division by zero. But if you take the limit of this value, you notice that it is approaches infinity. The divide by zero error is just a minor inconvenience that our mathematics model imposes.
    So, I concluded that from the point of view of light, time is stopped eternally.
    Interesting. It made me envision the universe as a static thing that I am moving through frame-by-frame, and envision conciousness as the entity that was guiding me through the universe, frame-by-frame.
  • Bzzt! If Schroedinger's equation is a pure diffusion equation -- meaning that given a start point for where a particle is, it's eventual location spreads over time. By your argument, all matter would have diffused to everywhere in the Universe by now, and there'd be no way to distinguish between your monitor, your keyboard, and your navel.

    The collapse of the wavefunciton isn't some sort of "Please save us from this craziness" cry for help that frightened physicists in the '20s postulated, it's a necessary part of the model to come close to matching reality.


  • There never was, there isn't and there never will be anything else but the present. Things change, not time. Thins change in the present. People get old in notime. The beginning and the end of the world is now.
  • It certainly seems more reasonable than the Copenhagen Interpretation. BTW, I remember also reading about another collapse interpretation that also did away with the observer/measurer; the basic idea was that the Scroedringer equation described the average/longer term wave behaviour, but that it masked shorter term fluctuations that included a very low probability of (spontaneous) collase. For entities at the level of subatomic particles, this doesn't really change much, but on a classical scale the probability of some wave collapsing in a very short time becomes almost certain, and causes the collapse of the entire thing...

    Thanks for the link - I'll finish reading it.
  • by Anonymous Coward
    M$ is phasing out the whole Time and Date nonsense with windows 2000. that's why in a recent interview when asked if windows 2000 would ship on time, steve ballmer said "That's not an issue."
  • If this is correct, then several hard questions like, "if I traveled back in time and met myself, would I remember having done it before I left," "...could I become my own father," "... if I killed myself, would I cease to exist" etc. become very easy to explain.

    You would remember having met yourself, since returning to any point that you had previously passed through defines that point as a place where there are two of you: you the way you remember yourself and also the "time traveller you" with the memory of yourself being that way. It's not hard to see why this is a requirement: if you weren't in two places at once when you got to that point the first time, then you can't actually arrive back at the same point.

    It also wouldn't be inconsistent to become your own father - simply returning to the old path through platonia at a previous point and marrying your mother while continuing along the same path would be sufficient. Of course, your father would have to remember being you, and you'd have some severe deja vu to deal with as you raise yourself.

    This brings up other problems, though. This means that time travel as we have typically conceptuallized it would be extremely difficult. To re-enter history where you remember it you would have to exactly match your velocity through platonia (direction and speed - there's no guarantee that once you start time travel that you're travelling at the same speed as the rest of us!), or else you will end up in a different reality than the one you experienced first. This is how you would explain killing yourself in the past - the positions in platonia where you had killed yourself are in a different location than where you experienced it before (ie. living to travel back in time) and the time travelling version of you would continue on its way, wondering why he still existed. The path you follow through platonia would look like a loop with just a few points of intersection, after which the paths diverge again. This could become very confusing if you ever returned again to another point in platonia further along your original path of travel; you'd wonder why you weren't dead anymore and if feeling guilty were justified.

    Logical extensions to this "time-travel" (if it can be called that anymore) scenario include the possibility of travelling to a "place" where you don't remember your past anymore, or to another "place" where people remember you doing something that you never did and won't ever remember doing. They might even have proof that you did it! For example: in their memory you committed a crime, they caught you on tape, and you left to go time travelling, and then the "real" you comes time travelling into their police station - bad luck. This follows from the assumption that there is no place in platonia that you couldn't theoretically go, provided that you exist at that point.

    You would need a good map of platonia to do this successfully; I don't think I 'd want to try for it otherwise. Too much opportunity for confusion. To be honest, though, I find this both appealing and horrifying from a religious standpoint. My religion teaches that God sees all of time spread out before Him from eternity to all eternity; if He did have a complete map of platonia then it would be easy for Him to be able to make that claim. On the other hand, having Him "know the end from the beginning" as other scriptures suggest implies that He perhaps controlls our path through the infinite possibilities, which contradicts the notion that I am free to do what I want or accountable for my actions. This discussion can become very interesting extremely quickly. I'll probably spend a good bit of time thinking about this in the near future... assuming that I can really call it that ;^)
  • For many years my dad would finish work at 5pm yet he'd be home by 4:45! Take that!!

    --
    Let's not all suck at the same time please

  • Oh YEAH! I already wrote a paper on this... and brought it up on slashdot a while back in a thread. And several people were calling me absurd. Oh well... Silly me.>:)

    Kintanon
  • If time doesn't exist, how do we have a Back and Forward button on our browsers?

    This theory is obviously wrong.
    I rest my case!

    #----------------------------
    $mrp=~s/mrp/elite god/g;
  • Basically we are reconciling the problems of our presuppositions by remodelling the universe into some bizarre conceptual form so that it adheres to what we observe. If the concept of time is introducing inconsistencies in what we observe, we must remodel our concept of reality to abandon it. On the surface the physics remain the same, but we have to do something fairly funky with the universe to explain it.
  • Time is an illusion, lunch time doubly so. - Ford Prefect : Hitch Hikers Guide to the Galaxy
  • That hat must taste good about now...
  • Why did I come to work early this morning? In fact, why am I putting in any time at work at all, if there isn't any?

    I would consider these questions more, but I'm going home...

    human://billy.j.mabray/
  • My project isn't overdue, the client has just narrowed his perception of the universe to three dimensions.
    -
    <SIG>
    "I am not trying to prove that I am right... I am only trying to find out whether." -Bertolt Brecht
  • He did earn a doctorate from the University of Zurich.

    That'll teach me to try and be a smart ass before I've had my coffee. :)
  • by Signal 11 (7608) on Thursday October 14, 1999 @03:54AM (#1614138)
    Assuming time doesn't exist, why is it that I always get to work late? Is it that I'm already at work and exist at home simultaniously (and thus I really am not late)? If so, they're not paying me enough!!

    --
  • IANARS (I Am Not a Rocket Scientist), but NOVA on PBS has a great episode on the nature of time, wormholes, and other really out-there physics. Yes, it's off topic, but it's on this week. Go see it.

    Of particular note:

    1) A person who says that he's seen microwaves go faster than the speed of light.

    2) Wormhole theory (with lots of chats with Hawking)

    3) If you've ever seen the light experiment where a light source goes through two slits in a wall, causing the light to split, you'll be curious to see what happens when they let only one photon at a time go to the wall. The result? Same as if you let all the photons through. Bars of light.

    -Mark

  • I have been toying with the concept of no time for quite some years. I have not, however, gone about it in a mathematical sense. I approached this subject through a model.

    First, we can all agree that time follows the same trichotomy axiom that the number line uses.

    if x is an integer, then x must be

    1. less than zero.
    2. zero
    3. greater than zero.

    if x is a point in time, then x must be

    1. less than present time (commonly referred to as the past).
    2. present time.
    3. more than present time (commonly referred to as the future).

    But this requires time to be infinite, which contradicts the idea of an initial time. This means that time is arbitrarily large.

    What follows is the key. Since we cannot know if x+1 exists, then part 3 of the axiom fails. Further, we can only experience the present, meaning we may not have truly observed the past. This causes enough doubt of part 1 to lead to failure. Thus we either have no time, since time must fall into the axiom, or time was not properly defined by the axiom and we only have the present time.

    That's been my theory about the whole thing. I may be wrong, but I did get a kick out of reading the article this morning that says I may be right as well.

  • how can I get to work? In order to move from one location to another, I need to have time:


    distance = rate x time


    If I can't get to work, I can't earn money. If I can't earn money, I can't own a computer. If I can't own a computer, how the hell am I going to read Slashdot?

    Try to answer that universal question!

    ~afniv
    "Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"
  • I know in my expirience, people (esp. scientists) love to use the expression, "Time/Everything is relative so..." to prove just about any point they want in a conversation. Now I can correct them and say no what doesn't exist can't be relative. I have been trying to figure this one out for a while, it is a somewhat old idea, and it's just plain confusing. I guess someone was smart/bored enough to finally gave at least some proof to it. Oh, yes and that junkmail email address does work, its just the address I use if I post anything, anywhere.
  • You're a hoopy frood!
  • Actually, what he's talking about is configuration space (the space of just positions of particles, in which a quantum wave function is usually defined) not phase space (positions and momenta in classical physics, or the Wigner function in quantum physics). The argument is gone into in some depth in the "one comment" link above - basically what we think of as effects of time (motion, interactions, etc) is somehow embedded in the configuration of particles rather than existing separately.

    The interesting difference here from the Many Worlds interpretation of quantum mechanics (though perhaps implicit in that) is a symmetry in ambiguity between past and future. If you go with Barbour's "Now", there is no well-defined past (rather there are many past Now's that could lead to the current Now) and similarly there is no well-defined future (there are many future Now's that could come from this one). Except that still somehow involves a path through the Nows, which Barbour disavows. But somewhere you have to explain our conscious awareness of time - perhaps that's where the solipsism comes in...

    But the idea of there being no unique past makes a lot of sense actually. I do find this a very interesting approach, even though I really still don't understand it.
  • by Trepidity (597) <delirium-slashdotNO@SPAMhackish.org> on Thursday October 14, 1999 @12:24PM (#1614146)
    Why would a 4D creature be stretched out throughout all time? We are 3D creatures, but that doesn't mean that we're stretched out throughout all 3D space - we exist in only some of it. Why wouldn't a 4D creature exist in only some part of time (much as we do)?
  • Agreed, collapse is a namby-pamby way of explaining things - I'm more convinced by the Bohm-de Broglie interpretation. Probably the point I was alluding to is that entanglement (whether from "collapse" or just plain non-local Hamiltonians) brings down the dimensionality of the state space, i.e. it reduces the number of dice that God gets to play with.

  • Abian presented the theory that time and mass are equivalent on sci.math and other scientific newsgroups. Basically, he thought that mass is consumed in creating time. Here [iastate.edu] is a summary of how he came up with this. (No real experimental data -- just a few necessary assumptions mathematically manipulated to make a coherent theory.) He extended his theories further to get the idea that:
    1) We should make massive changes to the earth to make it a better place
    2) We should bring Venus into a near-earth orbit so we can try out these changes on it first
    3) Some of the changes we should make are getting rid of the moon and un-tilting the earth

    He also had some non-crackpot mathematical writings on set theory.

    For reasons known only to him, James "Kibo" Parry has collected [kibo.com] some of Abian's postings, and his own responses to them.

  • it maybe too way out, and depends on your definition of 'exists', but as for objective reality you will find things changing but you can't find a thing or process you can label 'time'. So lets differentiate between 'rates of change' and some subjective metaphysical framework of measuring that change and comparing it with other changes. Part of this confusion, which seems to be rampant here, is the use of 'distance' in physical space as an ANALOGY of change, which we call time, which includes Einsteins use of the "4th dimension", which has some very good uses, but also creates some problems, notably the perennial problem of 'time travel' - which is clearly confusing traveling thru space with something that, uh, doesn't exist! That also relates to the physics problem of the 'direction' of the arrow of time. I can move back and forth in space, but 'time' just inexorably chugs on like an unstoppable juggernaught. Why CAN'T I 'travel' in time? This is also such a fundamental conception (space as an analogy of rates of change) that I suspect it is wired into the brain to happen automatically w/o consciously thinking, maybe related to motor function as an animal moving or running must look ahead and plan for 'future' movements, as in a few movements I'll be over there and must act accordingly, perhaps to escape a predator. Those that couldn't see the near 'future' were eaten. Anyway, those of a more religious or metaphysical persuasion will understand (probably why it isn't flying here, heh) - there's been books with names like The Eternal Now [amazon.com] etc. (it doesn't exist in print either :)

    In sum, memories exist, the past doesn't; everything is changing, but tomorrow never comes.
    Time exists in natural reality as much as centimeters, yen, or yardsticks do. If 'time' existed as an objective reality independant of the human (or animal for that matter) brain why would the bureau of standards have to erect expensive radio stations linked to extremely stable regularly changing events like cesium atoms to tell us what it is? Why would there be so many different calendars pegged to largely arbitrary events, like some dude's birthday or the founding of Rome or whatever.

    BTW, be sure to get NIST's Internet Time Synchronizer [bldrdoc.gov] and bug them to make a Linux version. I use it all the, ahem, time to keep these lousy PC clocks somewhere in the vicinty (isn't that a spacial term meaning close?) of a standard. And another thing: why do we keep having to add leap years and leap seconds to keep us earthlings synchronized with astronomical events like the transit of a particular star on a slowly slowing earth if the time we're so familiar with actually is an absolute?

    Chuck
  • very enlightening article even though some of the "science" was....a bit flimsy. obviously the author is hitting on a good idea, but the explanation was a little less than desired. still much enjoyment in reading the article. hope to hear more brilliance from the author soon. gotta go....wait time doesn't exist so i can sleep late.
  • Quantum theory talks about numerous probability waves, all of which overlap. When you describe an object in QM, you describe ALL possible behaviours and outomes. However, when you perform an observation, only one of those is ever observed.

    This is untrue. It also shows an incomplete understanding of quantum mechanics. (My understanding isn't complete either....)

    Go back to the famous double-slit experiment. If you have an opaque barrier with two slits in it, and you shine a beam of light (stream of photons) at the barrier, you get an interference pattern. That is to say, the photons act like waves -- starting at the exit points of the slits, they propagate outward. When the waves intersect, the result is the sum of the amplitudes (which are signed, remember) -- the waves may reinforce each other or cancel each other out, in a periodic pattern.

    But what happens when you emit a single photon at the opaque barrier? Newtonian physics would have you believe that the photon will go through one of the slits and then continue onward. But this isn't what happens -- instead, you still get an interference pattern! The single photon acts as though it were just a very short stream of photons. Or in other words, the single photon goes through both slits and interferes with itself.

    But in addition to this, we can see that observation plays a key role in the outcome of the experiment. Now this is where it gets interesting (to me). If you place a sensor at one of the slits, which is capable of determining whether the photon is going through that slit, then the outcome of the experiment changes. With a sensor on either of the slits, when you send a single photon at the barrier, you don't get an interference pattern any more. The act of observation influences the behavior of the particle which is observed. When the sensor is in place, the photon stops acting like a quantum mechanical wave, and instead acts like a solid object, either going through the first (monitored) slit, or going through the second slit, at random.

  • Even if the bubble of cosmos we inhabit is unbounded, it has a Value associated with it that represents the total Entropy in which it is embedded. This may be seen as a replacement for Newton's Framework of Time containing the mechanism of the Universe. If this value is referenced (or "paged") by each transaction, there is both sequence and snapshot value incorperated in every action, micro and macro cosmic. This is what "time" is. Experienced Duration is decoupled from Time. Ever attend a whole lecture that sounds like this stuff I just said?
  • Look at it like this.
    Without time, we couldn't see anything, feel anything, hear anything, smell anything, or even taste anything.

    Velocity is based on time, so nothing will move.
    Light and sound move on a basis of velocity....therefore......

    All in all.....nothing would move and nothing would exist. (provided time doesn't exist.)
  • That's an infinite improbability drive.

    The best part is the story behind it's creation... (poor kid)

    (If you have to ask, buy the #^%#% book.)
  • First of all, life does not decrease the overall entropy of the universe (although it does locally). And you can't say 'locally is good enough for me', since without a source of low entropy (for life on earth read: the sun), life would come to a standstil.
    I don't know, but probably somebody has done the statistical mechanics of superclusters, and I would be highly surprised if they decrease the entropy of the universe.
    Lastly, I think that the entropy of black holes is actually huge (Stephen Hawkings has calculated this stuff). So it does not vacuum entropy away. Also, black holes can actually evaporate (in 100 billion years or so), again this was discoverd (invented?) by Hawkings. This doesn't do much for entropy reduction either.
  • I didn't forget it.
    1) If time doesn't exist then the problem doesn't exist either. There is just the discrete set of matter and energy that is right now.
    2) If time does exist (it doesn't) then the infinite amount of matter makes conservation really easy - the amount can never change.
    BTW: Energy is also imaginary. It's only required if you are forced to push matter around in time.
  • I could have sworn cheese was the most powerful force in the universe.

    Behold the power of cheese!

  • First of all you'd need 12 numbers, not 10 to describe the location of 3 points in Newton's universe. Maybe he assumes that all 3 points exist at the same time. But he should state these assumptions, especially in an article about time.

    In Newton's universe, there is absolute time. So if you're specifying the the state of the universe at a particular time, why would you want three separate times?

    His rules for Triangle Land would sweep out a plane, not a pyramid. Maybe he's leaving some other assumptions out. It would be useful to see the diagram he refers to to find what defines the axis extending from his Alpha point.

    You just failed to understand what he was saying. Okay, imagine a standard a set of standard xyz axes. The x axis is the distance between particles 1 and 2, the y axis is the distance between 1 and 3, and the z axis is the distance between 2 and 3.

    So the point (x, y, z) is a point in Triangle land, for all positive x, y, z. Which means that Triangle land is composed of the entire first octant of a standard 3 dimensional space, with each point representing a possible state. The 'apex' is at (0, 0, 0), which is where all particles exist at the same point (or more specifically, where the distances between the particles are all zero).

    His mention of a particle's spherical wave function misses the point that the function breaks down when observed. It then takes on a single value. The path taken by the Alpha particle sweeps out a sphere until you look. It then becomes a particular path. Schrodinger's Cat only exists as a wave function until you open the box. After that it's just an ordinary cat.

    I don't think you understand the uncertainty principle very well. For a wave-particle, the product between the uncertainties of the position and the momentum can never be below a certain value. So the more you know about the position, the less you know about the momentum.

    But a straight track in a cloud chamber imples that you are learning both position and momentum, since you can extrapolate the rest of the track from a small part of it. This is in direct contrast with the uncertainty principle.

  • What if this theory gave a theoretical basis to something that could not be predicted from existing theory, rather than observation? The author suggests that maybe this model will permit the cosmological constant to be derived theoretically. IANATP (I Am Not A Theoretical Physicist), so I can't speak to just how easy/likely/possible this would be, but if this does turn out to be the case it would be a point in favour of the theory.

    BTW, it seems strange to me to use the word "predict" in relation to a theory that abolishes the concept of time. When a scientist speaks of "prediction", she usually doesn't mean a statement about an event that will take place in the future, but rather a statement about an event whose outcome is unknown from the point of view of the predictor. This applies to all future events, but it also applies, at least imaginatively, to any past event whose actual outcome was not taken for granted when the theoretical "prediction" was made. Maybe a word like "idiodiction" would capture the idea better.
  • Cramer's transactional interpretation always rather reminds me of the data assimilation process in modern weather forecasting systems.

    The measurements from a single time point are not enough to fix the state of the weather model, so the model state is estimated from all the data gathered over a 24-48 hour period. One approach (4D-var) is to run the model forward, note the differences between the predictions and the observed data at each stage, then propagate these difference fields backwards in time to produce an improved estimate of the initial conditions. After several trips forward and back, the model should coverge to its best estimate of the historical path.

    Cramer's model is rather like that: the measurement system is a vital boundary condition which changes our best estimate of the entire history, so Cramer assimilates it by propagating the mismatch backwards and forwards to convergence. This is a great way to picture the Copenhagen interpretation, underlining its insistence that an experimental quantum mechanical system is not completely specified until the macroscopic measurement apparatus is specified.

    But I do prefer to think of TI as how an imaginary computer might cope with assimilating the asynchronous information into a model, rather than having to invest too much ontological reality into his 'propose' and 'accept' waves.

    For myself, I believe the most fundamental thing about QM is that it forces us to abandon the idea of a space-time of completely independent points -- the universe just doesn't contain that much information -- and instead there is always a sharing of information between a point and its neighbours. So I'm not too bothered that there appear to be, at the least, a non-local superselection rule connecting a quantum object and its measuring device. Treating them as probabilistically independent is an approximation -- useful, but wrong.

    If we now alter our approximation to reflect the interdependence, we should not be surprised that we must also alter our best estimate of what the test object is doing/has done. But this is a sudden change in our knowledge (epistemology), not a sudden change in reality (ontology). Doing so, we will infer a new, consistent trajectory for the combined object+apparatus system, which is just like the final version of history left in Cramer's TI, once all the to-ing and fro-ing is done: a smooth, deterministic evolution, without any sudden jumps or discontinuities, and no identifiable quantum measurement 'event'.

    ((Footnote: to hedge my bets, I should also say that I'm quite impressed by Zurek's decoherence calculations, which I suppose support MWI; though I'm not sure whether they help much with EPR))

  • Hasn't anyone read that book? All this stuff is explained in detail, and IMHO, quite satisfactorily.

    You can buy the book from amazon [amazon.com].
  • There are *no* areas in Classical General Relativity when time ceases to exist.

    If somebody has a relative velocity with respect to you near the speed of light (only massless things can actually have a relative velocity of the speed of light) the you will percieve time to move slower for that person, just as they will percieve time to move slower for you.

    Again you will percieve time to move slower for sombody that is closer to a strong gravitational field than you are. If you take the limit of infinite space-time curvature then this looks like time stops. (But also the theory breaks down - while you can learn a lot by modelling black-holes etc by singularities, a singularity in the thoery does mean that you are applying it outside it's range of strict applicability).


    Neither of these is time *not existing*, at the most looking like it's stopped, but the concept still makes sense. Even if there is something 'more fundemental' explanation of what time is, the evidence for the current models is so strong that that the new explanation will have to look just like the old one in most situations we can observe (just like special rel looks like newtonian mechanics if you move slowly enough).

    Sorry for being so pedantic.
  • >>Meaning that there would be an infinite amount of matter spread across the so-called space-time continuum. Now that's an ugly situation.

    >Only if the universe is infinite.

    Or if time is infinite.
  • I kind of respect people who try to do physics as a hobby, although it's hard to imagine that anyone could have enough spare time or resources to make a significant contribution.

    Hmmm.... Wasn't there a patent clerk around 1905 who published some physics papers, that he did sort of as a hobby, while he wasn't busy reading patents.

    I think his name was Albert something....

    ...richie ;-)

  • by Anonymous Coward
    Benjamin(sp?) Franklin did most/all of his studies as a hobbist and he's lauded as a world renown scientist. There are others as well, but I don't feel like spending time to list them all.
  • >Each observation collapses the wave function,
    >resetting the clock, and it is possible by this
    >means to delay indefinitely the expected
    >transition to the lower state. ..

    So if you watch a pot closely enough, it really will never boil?
  • AHA! So God DOES roll dice! heh

    One obvious feature of a universe like this would be that time travel of any kind would be impossible. There would be an infinite number of states you could have come from or could go to.

    So our parents were right when we asked why something was and they said "because it just is". Maybe they should have said "because anything else would be much less probable".
  • (From Abian's paper)
    . At the primeval stage, the Cosmic mass was violently sucked out from its primeval state (perhaps as a primeval fireball) and with a furious and tempestuous force was fulminated into the Space giving rise to the existing Cosmos. I call that stage "The Big Suck Stage" and the corresponding theory "The Big Suck Theory" (contrary to the currently held "The Big Bang Theory" which is nonconvincing to many).

    Well, it certainly does suck.

    I appologize for shamelessly nicking that from Wayne's World.
  • Oh no...question too deep...must...stop...pondering...or...brain...will ...implode...
  • by slew (2918) on Thursday October 14, 1999 @08:55AM (#1614215)
    Although I'm arguing that the above metioned article is or isn't valid science, I don't
    think that being a physicist has any very much to do with the ability to judge "newsworthiness"
    of scientific blurbs that occur in mainstream press articles that have no details provided,
    unless, of course, if he/she is involved with that research.

    A particularly astute visionary, Richard Feynman (who by the way was also a physicist) observed
    that often what passes as scientific judgement is often a thinly diguised religion.

    As evidence, he observed the written record of the discovery of a "new" particles in the literature.
    Basically, looking back he discovered that early experimental results that could have indicated the
    existance of such particles were routinely dismissed as experimental error. After more
    "support" for the particle existed, the experimental error started to be tracked and
    eventually a "new" paradigm emerged.

    Feynman surmised that there would have been even more historical reasearch to support the "new"
    paradigm earlier, but noted that some researcher often "threw-out" experiments that didn't verify
    their theories or fit their agenda. So much for the integrity of scientific judgement.

    That's not to say that scientists (or physicists) are alone in this type of behaviour, it's human.
    It's only natural to have such a filter. Since there is only a finite amount of time in a day,
    people often build up "BS" filters that help to keep them from wasting time in probablistically
    non-productive pursuits.

    On the other hand people with journalism training tend to recognize this type of bias and tend to be
    better prepared to compensate for it. So IMNSHO, I think a person with a background in journalism
    who also happens to know a bit about science is much more qualified to be a science editor.

    (BTW, that's not me...)

    I'm not saying that having a physics background isn't useful, but I seriously doubt that physics
    background alone make anyone more qualified to be an editor than your typical techno-geek that
    watches the discovery channel on a regular basis and is a sceptic and has good BS detector.

    (and that's not me either...)

    However, having said that, techno-geeks that watch the discovery channel aren't necessarily qualified
    to be editors (or physicist) either, it's just that neither is a very good indicator of being a
    good editor.

    But people who can critically read and comment on things that they vehmenantly disagree with,
    well, that's a good start... However, the ability to take criticism because you know that not
    everyone will agree with your decision to run with an article, that's probably the #1 criteria...

    From what I've seen so far most of the /. editors can pass this #1 criteria...
    (having edited a newspaper before, I can definitly sympathize with the /. editors on this point)

    -slew

    (oh yeah, I studied physics too, but not volunteering for any jobs...)
  • by The Iconoclast (24795) on Thursday October 14, 1999 @06:55AM (#1614234)

    Meaning no disrespect to Hemos, CmdrTaco, etc., etc., Slashdot realy needs a "science editor." Someone with an appreciable knowledge of science. This article is quite a heap of crap, from a scientific methedology standpoint (to say nothing of the lousy "physics" involved).

    Anyway, most of the time, the /. editors put decent ideas and stories up, but from time to time, things like this get through. This story is filled with misinterpretations and omissions of quantum and general relativisitc theory.

    One does not have to know evrything there is to know about all fields of science to determine what is valid, but one needs a basic understanding of each fields underlying principles as well as the use of scientific reasoning. These skills and knowledge one can learn from a decent undergraduate eduaction in the "hard sciences" (Physics, Chemistry, Biology, Astronomy, etc.). An undergradute eduaction in these fields is not the ONLY to recieve this knowledge, either. They are just the ones classically recognized as providing a decent platform onto which one can learn about other types of science. The anaylitical skills learned from these fields allow one to anaylize other's scientific arguments based upon their scientific merit and reasoning.

    I would like to propose that, in particular, Physics gives an excellent background on other sciences as well as the needed training in scientific reasoning. Hey a guy can have a small bias can't he? :-) Anyway, the concepts learned in an undergraduate physics program have applications in almost every scientific and engineering field (uh oh, I said the dreaded E-word :-) One learns about the scientific method, Newtonian Mechanics, Thermodynamics and energy, Quantum Mechanics, Electricity and Magnatisim, Materials Physics, and Relativity. This stuff won't tell you everything there is to know about Biology, Chemical Engineering, Computer Science, or whatever, but it does get you quite a bit along the way.

    I am sure other disciplines teach the analytical thought processes and most of the topics I mentioned. However, physics is the study of how everything works, so it is kind of broad :-)

    Anyway, I'm sorry if I sound like a snot. I'm not trying to berate other sciences. I actually think that the skills any science teaches are essential in being able to discern what is valid and what is not, at least from a scientific viewpoint.

    As you can probably tell, I am a physicist. I am at the Depatment of Physics [cwru.edu] at Case Western Reserve University. [cwru.edu] Email me if you want. It should be easy enough to figure out my real address. I'll get off my soapbox now :-).

  • First some background. It is clear to anyone who has studied Special Relativity and/or Quantum Physics that the "common" perception of time just doesn't work. Special Relativity shows that two events that are simultaneous according to one person are not simultaneous according to a person with different motion. Quantum Physics shows that, on a subatomic scale, time is non-linear, and can even be percieved to run in reverse.

    It's clear that we need a new concept of time that incorporates what we currently know. Barbour offers us one. It's not earth shattering, since it offers no new verifiable predictions, but it's a viewpoint that might just help someone else come up with something earth shattering. Rather than standing on the shoulders of giants, he peeks over and takes a picture so the rest of us can see.

    ----
  • Which is exactly what I describe. The first case, you are not observing the photon directly, so the probability waves don't collapse. In the second case you are, so they do.
  • His argument, concerning straight tracks, are this kind of error. He's looking for the integral of a probabalistic wave (as he's looking over a period of time), but he's getting the raw, collapsed wave instead. If you look in the wrong places, you are bound to not find what you expect.

    When you receive a radio wave, you don't collapse that wave into a photonic particle (which is what the radio wave is, if it could be collapsed). For a QM probabalistic wave to collapse into a particle, you must do more than measure it's existance--you must measure it in such a way as to force a measurement of it as a particle.

    And that's just it: if you simply look at the release of an alpha particle by itself, it should produce a uniform ionizing radiation "sphere" around the decaying atom. A cloud chamber does not inherently differentiate between a unform sphere of radiation (a wave) and a decay particle, so simply observing with a cloud chamber should not force the probability function to collapse.

    What the article suggests is that it is the interaction between the alpha particle and the cloud chamber, rather than simply the observation done in the cloud chamber, which forces the probability function to collapse.

    Overall, I have no problems with time, at least at a quantuum mechanical level, not existing except as a consequence of the configuration of the probability cloud. Just as I have no problems with the atoms of my body being nothing more than a consequence of the spacial collapse of a very large probability cloud. It all seems real, and it's the perception of reality around me that's important to my day to day life.
  • Actually, said program was on earlier in the week, so sorry to all you /.'ers who didn't get the privilege of seening a awesome show on wormholes, quantum physics and time travel.

    (Oh, wait, if there is no time, then how could it have been on earlier in the week?)



    It wasn't, you only think it was because you were created with the 'memory' that it was. Just as I was created with the memory that I wrote this post, even though the post was just created as well.>:) I only think I remember typing the letters before these.

    Kintanon
  • "Anyway, what happened to quantum causality. Doesn't that make an arrow."

    Time flies like an arrow.
    Fruit flies like a banana.
  • Maybe they should have said "because anything else would be much less probable".


    lol

    That's just the kind of thing a kid would understand.

    If you believed in chaos theory would god "be" the dice?
  • Time is God. or at least what most people think of it as. They are nearly interrchangable. "It is all done through X." "X is all-powerful. all-knowing, and everywhere."

    They are both understood at about the same level "God does not Exist!!" (That's was the major philosophical break for thr ren.). The given of the equation.

    That's my personal philosophy at least, it goes on, but not here. Gotta website comin' soon...
  • The concept that matter spacetime can be represented as "rotating" in four dimensions isn't all that farfetched--as an object devotes more of its being to change in spatial position, its internal processes appear to "slow", reflecting a rotation out of time.

    Now, I'm bullshitting out of my ass here, but it's a convenient way to think about time dilation.

    Anyway, my main argument against a timeless universe is that it makes some tremendous assumptions about the information storage content of the universe. If anything can travel "backwards" in time, all particle states would have to be remembered in one form or another. One would be able to store an infinite amount of data on a single floppy by merely constantly rewriting the disk and using timeseeks to access previous disk states.

    However, there is no conceptual problem with particles, structures, or even objects moving forward in time but with all subatomic processes moving backwards--we can watch, in forward time, video playing back in reverse and yet not suffer a time paradox. Reactions are simply occuring backwards. There is evidence that reactions occur backwards, but saying that they're reactions from the future moving back to the past requires far too many presumptions about the structure of the universe.

    Enough from me for now.

    Yours Truly,

    Dan Kaminsky
    DoxPara Research
    http://www.doxpara.com
  • Think big bang. Think all of reality in a peapod. Time is still. Or is it. Boom, everything starting spreading, growing, like a little flower.
    Now think about the sign we have for infinity. ya'know that twisty thingy. Now look at all the patterns of life in death in nature. Fron half-life to earthquakes (hehe). Now think of black holes. Sucking in everything, even other black holes. mmm, black holes. Now think of matter all compacting to one space, one time, one peapod. Rinse, repeat.

    Throw in free will and chaos (quantum craziness) and you have a hell of a fun game.

    Coming soon to your Playstation10^9
  • I said {NT}
  • Bzzt! If Schroedinger's equation is a pure diffusion equation -- meaning that given a start point for where a particle is, it's eventual location spreads over time. By your argument, all matter would have diffused to everywhere in the Universe by now, and there'd be no way to distinguish between your monitor, your keyboard, and your navel.

    Actually, it wouldn't diffuse :-)

    But it is very easy to think that it would, from the typical undergraduate wave mechanics course -- I know I did!

    The very first exercise everyone does is to show how a gaussian wavepacket inexorably spreads out; and then after that the only localised states you ever encounter are bound states, with the quantum object penned in by an ever growing potential -- which seems quite inappropriate for a macroscopic object, because the potential would have to be enormous.

    However, in fact quantum mechanics doesn't predict that everyday objects should diffuse off to infinity; and the reason why is a purely wave thing -- it works just as well for sound and vibration. Finding this out probably gave me a bigger shock than any other misconception I suddenly realised in my undergraduate physics course, and I think it's something which is criminally under-emphasised in the teaching of wave mechanics: you don't need quantum measurement to explain why apparently free macroscopic objects are localised.

    The revelation was a phenomenon discovered by Philip Anderson in 1958 in a paper he called "Absence of diffusion in certain random lattices". (They later gave him a Nobel prize for it.) Anderson's result was that the eigenstates of quantum objects actually are spatially localised, even for very small absolute differences in the potential function (much less than would be needed for a bound state), if the potential is not smooth but disordered.

    In fact it is now known that in 1D and 2D any magnitude of disorder, however small (so long as it persists throughout the surface), will produce exponential localisation. And this is not some strange quantum phenomenon; it happens for any waves -- the same mechanism for example can cause vibration energy to get trapped in a small part of a large engineering structure. In 3D a rule of thumb is that the energy will be unable to diffuse away if the effective scattering length is less than one wavelength (the Ioffe-Regel criterion).

    Now for a macroscopic object, the de Broglie wavelength is very very small. But I think the effective scattering length is even shorter. The key is the disorder of the object itself. Even if each of its constituent particles are experiencing quite small local potentials with a slow spatial variation, these all have to be added together to give the potential seen by the centre of mass. Even quite a gently changing potential has spectral power implicit in the higher modes of its fourier transform; but adding together all the different contributions effectively amplifies and phase randomises these frequencies. So the potential the centre of mass sees will have real high spatial frequency oscillations -- it won't be smooth at all!

    That is why the effective scattering length for macroscopic objects in a typical environment is in fact even shorter than the de Broglie wavelength; and thus why the "good quantum states" for my monitor, my keyboard and my navel are all very strongly Anderson localised.

  • by jd (1658) <<moc.oohay> <ta> <kapimi>> on Thursday October 14, 1999 @04:25AM (#1614326) Homepage Journal
    Let's take the following Greek puzzle: If someone fires an arrow at you, and you blink at a given rate, then the arrow travels a finite distance between blinks. The faster you blink, the shorter the distance. If you blink fast enough, the arrow remains stationary.

    Why doesn't this work? Simple. This is simply a misunderstanding of Calculus. Mind you, as calculus hadn't been invented then, they can be forgiven for misunderstanding it. As dt approaches zero, dx/dt approaches the true rate of change at -that point-. It's an instantaneous rate of change, so you don't see the effect of it, for that instant, but it's still non-zero, so an effect will occur.

    How does this apply here? Here, the reverse has happened. This guy is looking at the INTEGRAL of time, and confusing that with time itself. If you take a line, and integrate it, you will get an area. An area isn't a line, and does not visibly consist of lines, but a simple differentiation will show those lines must exist.

    His argument, concerning straight tracks, are this kind of error. He's looking for the integral of a probabalistic wave (as he's looking over a period of time), but he's getting the raw, collapsed wave instead. If you look in the wrong places, you are bound to not find what you expect.

    IMHO, this is very poor science. Any school-age kid who's done maths has done calculus, and knows this very simple pitfall. There is NO excuse for it.

  • usually, the direction in which time flows is the one in which the entropy (degree of disorder) increases. That is, say you have snapshots A and B of a piston with 1 million gas molecules.
    A: all 1 million molecules randomly distributed throughout the piston
    B: all 1 million gas molecules very close to the bottom of the piston
    The chances of situation B occuring by chance are exceedingly small, and were probably caused by compression of the piston or so (and the piston was expanded and immediately after that the snapshot was taken). In any case, moving from situation A to B by chance alone can safely be ignored, so time B is before time A. That's all there is to it; all the other laws of nature appear to be time-invariant.

    Now, *how* the universe could have started with such an incredibly low entropy (== high order) is anybody's guess; fact is that the total entropy keeps increasing, and that's what we observe.

    Now, you can play word games using the anthropic (!= entropic !!) principle: if the universe did not start with such a low entropy, who would have been there to observe it and argue about it on slashdot :-) So perhaps that's where the beholder bit comes in. But I should read the original I suppose.

  • You are correct. It is supposed to be silly. What you're saying with the arrow is supposed to be right. Isaac Newton spelled it out, very
    completely and correctly.

    BUT.

    Newton turns out to be wrong on the subatomic level.

    I don't understand why people continue to try to use imagery such as flying arrows to explain the problems in quantum mechanics. You're supposed to be correct. But then experimentation comes along and consistently finds results that can't be explained like that.

    You can't say "QM is bullshit because Arrows don't stand still when you blink."
  • The fact that the author's book is published by Cambridge Univ. Press tells me that he is no hack.

    There are a lot of interesting people like Paul Erdos [oakland.edu] at the bleeding edge.

    My first year physics prof [nobelprizes.com] at Tufts U. shared a Nobel Prize for something he worked on in his basement during free time completed unrelated to his main research topics.

    Since a lot of great physics is done in the early life of a physicist, it is not surprising that there is a lot of amatuer flavor to it. Many of Einstein's ideas leading to relativity were framed when he was 15 or 16 years old.
  • That article was highly interesting. Tell me though, as you read the discussion of how we perceive time and motion, was anyone else thinking what I was thinking? "Infinate Improbability Drive"! Movement by altering the probability mist of the Platonic landscape. Make the improbable more probable and suddenly your there. No 'movement' needed at all. Hmm... Ok, Mr. Douglas Adams, maybe that flying thing has some potential after all. ;)
  • by GnomeAttic (97126) on Thursday October 14, 1999 @04:34AM (#1614346) Homepage
    This "time doesn't exist" thing really puts a damper on a very large and hilarious group of jokes. For example, "What time is it when an elephant sits on your watch? Time to get a new watch!" Will now have to be updated to "What time is it when an elephant sits on your watch? An interesting article suggesting that time is an illusion of perception has appeared at New Scientist...". I suggest that , as mature adults, we squelch this discovery for the good of all mankind, so our children and our children's children can enjoy this diverse category of jokes.
  • Cool! That means that I must have been imagining all that crappy journalism!

    Makes me feel better about the world that Time never existed.
  • If time is real, when did time start?

    --
    Interested in XFMail? New XFMail home page [slappy.org]
  • by Anonymous Coward
    If I told you temperature does not exist, because heat is nothing more than a measure of the avarage kinetic energy of the particles that compose an object, which quantum mechanically should be described as a linear combination of an (almost) infinite number of wavelengths and can not be measured directly, would this be posted on slashdot as a great new scientific insight, or would I be advised to stick my head in an oven at various temperature settings, to see if I can spot some of those wavefunctions?
  • According to Classical General Relativity, there are only 2 areas where time ceases to exist:

    A singularity, where the Curvature of space is infinte and there exists something with a volume of zero and infinite density. Time and General Relativity Break down here.

    Velocities at the Speed of light, time dialation becomes infinte and time stops for anything with a velocity of c.

    From what i can understand from this article is Time does not exist on a Universal scale, it is kind of like the homogenity of the universe. 'The universe is symmetrical only on a universal scale'. In other words time exists when your reference frame is smaller than the whole universe.

    However, If Time just dosent exist, i wasted allot of nothing on a paper on singularities which is compleatly misguided as of this new (wait it can't be new b/c there isn't time) research.

    Argh i'll prolly have to fit something on this in my conclusion,
    oblisk

    P.S. Thank god for the slowness of radical ideas acceptance in science.
    ------------------------------------

  • There are maybe 3 people in the world still working on wormholes (one is Matt Visser who wrote a nice book on wormholes - can't find the reference right now - in the wrong office so I can't see it on the shelf).


    Work [lanl.gov] done by Ford and Roman showed that to have a wormhole you need stupendously large amounts of negative energy density to maintain the throat of the wormhole (what you would travel through). Think millions of galaxies worth of mass stretched over an area smaller than 10^(-19) meters thick.


    Work [lanl.gov] by Taylor, Hiscock, and Anderson (yes I'm Taylor) showed that even the simplest kind of matter field you can imagine, a scalar field, will not support the wormhole throat. The other fields' (fermionic, electromagnetic, and gravitational) effect have not been calculated because they're much too difficult in this case, but in simpler cases they vary from the scalar field by a factor of 2-4. This isn't nearly enough to maintain the wormhole throat.


    Because of all these problems (and others), most everyone has abandoned wormhole research for the time being. There are hints (work by Tanaka) that it may be possible, but it seems very unlikely in the general case that we can create or maintain a wormhole (if we happened to find one suddenly).

  • by Ted V (67691) on Thursday October 14, 1999 @05:00AM (#1614396) Homepage
    Here's a brief explanation of the article:

    Consider the set of all possible configurations of all particles in the universe. (He names this set Platonia.) Arrange the set so that configurations which are similar are close to each other. In other words, the configuration where I've just gotten out of my chair is close to the configuration where I'm about to get out of my chair, but they're both really far from the configuration where I'm on an airplane flying to Bombay.

    He then defines the "arrows" of time as a straight "track" traced between different configurations. Each configuration contains data which has records of "the past"-- other configurations on the same track. Essentially he's changed the definition of the Universe. What we consider "the universe" is a single element of the set he names Platonia. But he names Platonia the universe-- the set of all possible particle configurations.

    Let me use his arguments to prove that distance doesn't exist. "Consider what we think of as points on the real line. The point 1 and the point 4 have a distance of three. But there's really an infinite number of points, and they're all connected. I will define the real line R as a point. Distance has no meaning to the real line so distance must not exist! What we think of as distance is really just the separation between two different instantiations of our point R." Technically stated this is true. He's redefining terms in such a way that they're no longer meaningful.

    On the bright side, if he could get from "Time doesn't exist" to "consider a set that contains the concept of time", he might be able to theorize something useful.

    I'm going to comment on his credentials in a later post...

    -Ted
  • Ok, what he seems to be saying is that every possible configuration of the universe has some probability, which is determinable by plugging that configuration into some equation (who knows what this thing looks like).

    Now, in the set of all possible configurations, there are bound to exist configurations that LOOK as if they are a time evolved state of another confuration. In other words, state B is configured in such a way as it appears to contain information imparted by a previous state A.

    But in 'reality' they are merely two status in the 'mist' which have some finite probability of 'existing'. String enough of these states together in a sequence and you get his 'time capsules'.

    Ok, interesting mind candy, but it does not seem like there is much here to chew on for the real physicist. My understanding of physics is that is about the production of mathematical models which should predict the real, observed behavior of physical systems.

    The progression of time is an observable. Just about every observation one could wish to make will involve time, whatever it is, even if it is an 'illusion'.

    If you were to produce a theory that did not contain time you would have to demonstrate how time appears to come into being in some special cases (and demonstrate it a little bit better than with some speciously reasoned 'time capsule' argument), and demonstrate that your model not only describes all currently obsevable physical behavior properly, but in some way BETTER than other models.

    -josh
  • by jd (1658) <<moc.oohay> <ta> <kapimi>> on Thursday October 14, 1999 @05:21AM (#1614400) Homepage Journal
    Ok, my reasoning is thus:

    When you look at something over a period of time, you are effectively performing an integration with respect to time. (In fact, this is true of all experimental science. There is no such thing as an instantaneous observation.)

    However, the integral of time is, clearly, not going to be the same as time itself, the same way that the area under a curve is not the curve. The two are related, through the logic given by Calculus, but are otherwise completely distinct.

    QM adds some further complications, here. The act of observing something affects the observed. As you are observing over time, rather than instantaneously, you are going to have an impact that is also over time, not simply instantaneous. This needs to be taken into consideration, when looking at behaviours, and I honestly didn't see that.

    In quantum mechanics, you have a further complication. Quantum theory talks about numerous probability waves, all of which overlap. When you describe an object in QM, you describe ALL possible behaviours and outomes. However, when you perform an observation, only one of those is ever observed. One solution to this has been to say that the wave collapses in =this= universe, but that there are as many universes as possible states. The QM definition is thus the integral across all possible universes.

    However, the same logic must apply. The integral is not the same as the original function. Here, the model is the integral, and what you observe is the original, which is the reverse of the situation above.

    In summary, when you observe an object, you observe it as an integral over time, not instantaneously, and you observe it in one universe, not the integral over all possible worlds.

    I believe the article confuses the instantaneous with the integral over time, and one universe with the integral over all possible universes. When handling data, it's very easy to slip up and compare data of the same type but the wrong order. It's not like oranges and apples, where you can see the difference.

  • The author's reasoning seems incomplete in some ways.

    First of all you'd need 12 numbers, not 10 to describe the location of 3 points in Newton's universe. Maybe he assumes that all 3 points exist at the same time. But he should state these assumptions, especially in an article about time.

    His rules for Triangle Land would sweep out a plane, not a pyramid. Maybe he's leaving some other assumptions out. It would be useful to see the diagram he refers to to find what defines the axis extending from his Alpha point.

    I'd say he's still firmly in Euclidean space however uncool that may be these days.

    His mention of a particle's spherical wave function misses the point that the function breaks down when observed. It then takes on a single value. The path taken by the Alpha particle sweeps out a sphere until you look. It then becomes a particular path. Schrodinger's Cat only exists as a wave function until you open the box. After that it's just an ordinary cat.

    He seems to be stirring a lot of concepts together, but instead coming up with chocolate chip cookies he ends up with a gooey mess that we can't sink our teeth into.

    I'd say the topic was time, but the substance was bogon.
  • Is worth a read on the concept of time. Vonnegut's Trafalmadorians see all of time, such that when they see you, they see you from infancy to death and that we're all just kind of like bugs in amber.

    The protagonist, Billy Pilgrim, is unstuck in time; i.e., he jumps backwards and forwards in time.

    The best part is the Trafalmadorians' description of human perception of time, something like strapped to a locomotive barreling forward with nowhere to look but ahead...

  • I've always felt that the mainstream Quantum Theory interpretations are way too conservative, and seem to be driven by a desire to make the percieved classical world real.

    IMNSHO, Schroedringers equation describes the world - period. The collapse postulate is bunk, as only serves the purpose of supporting the classical view.

    The correct "interpretation" of Quantum Theory is therefore that the world actually is an evolving "probabalistic" wave equation. As classically scaled creatures, our classical perceptive systems naturally see a "collaped" view (although if reality there is no collapse), and the path of time we experience is just the history of this percieved collapsed event history.

    There again, I might be wrong! ;-)
  • by Ted V (67691) on Thursday October 14, 1999 @05:12AM (#1614431) Homepage
    This article has all the ear marks of a crack pot theoretical physicist whom no one listens to.

    The author of this article, Julian Barbour is an independent theoretical physicist who lives near Oxford, UK.

    First, notice how he's not actually working at any university, but cites that he "lives near Oxford" as if that makes him smarter. He also does NOT state what kind of degree he has and where it's from. (Not that degrees make one smart, but when the rest of the article is suspect, the degree is too.)

    Consider this paragraph:

    The notion of time as an invisible framework that contains and constrains the Universe is not unlike the crystal spheres invented centuries ago to carry the planets. After the spheres had been shattered by Tycho Brahe's observations, Kepler said: "We must philosophise about these things differently." Much of modern physics stems from this insight. We need a new notion of time.

    He's basically saying, "You might think I'm crazy but I'm really as insightful as Kepler! Save yourself the embarassment and support my ideas now!" Of course, Kepler actually came up with real equations, and Kepler's Laws provided meaningful insight into planetary motion. This article's author has not provided anything useful.

    Here is the best support he can muster from other physicists:

    Americans Bryce DeWitt and John Wheeler combined quantum mechanics and Einstein's theory of general relativity to produce an equation that describes the whole Universe. Put into the equation a configuration of the Universe, and out comes a probability for that configuration. There is no mention of time. Admittedly, the Wheeler-DeWitt equation is controversial and fraught with mathematical difficulties...

    Wow, his best cite is contraversial and came up with a useless mathematical equation. He's really just using the idea that for any configuration of the universe, there is a probability that it exists. (But doesn't his article state that all configurations of the universe exist? We just experience them one at a time? Hmmm, sounds like a contradiction...)

    The feeling I got from reading this article was that the author wasn't taken seriously by the academic community because his ideas are some subset of: {Trivial, Unprovable, Useless}. If this is an average article for Julian, then I agree with the academics.

    -Ted
  • ...of how many dimensions a creature can perceive:

    Number of Dimensions = (Number of Eyes + 1)

    Human:

    Eyes: 2

    Dimensions: 3 (Length, Width, & Height)
    Evolved Human:
    Eyes: 3

    Dimensions: 4 (Length, Width, Height, & Time)
    Common Arachnid:
    Eyes: 8

    Dimensions: 9, making them the wisest beings on the planet.

    My plan is to use spiders to predict the future of the stock market, and grow rich off of as of yet unknown bio-medical research groups. The spider tells me that any company that engineers "crop-protecting superbugs," is a good bet.
    But...perhaps I have said too much...

    -AP

  • by ElrondHubbard (13672) on Thursday October 14, 1999 @05:46AM (#1614450)
    ISTM that confusion like this arises because people confuse real space with phase space. The alpha particle in the bubble chamber leaves a linear track in real space (i.e. the space that we perceive), even though it's "really" an expanding spherical wave in phase space. What the guy is talking about in this article is basically viewing the entire universe not as an entity that unfolds linearly in time, but holistically, as an enormous polydimensional phase space. What we perceive as time and history results because different parts of the phase space have higher probabilities than others, and our brains construct our perceptions by stringing together, for lack of a better word, "samples" of congruent areas of this space.

    The part that I find really interesting is the Alpha point, where by definition all particles occupy the same point. This corresponds eerily well with the Big Bang. The idea that the "history" of the universe is just the distance, in phase space, between us and the Alpha point, is an elegant one. I like this theory.
  • Please, people, do *not* confuse the probability wave of a particle with the particle itself. And second: Quantum mechanics itself is not very accurate, take quantum electro dynamics (QED) instead. For those who can read, but can't do math, there's a very fine book about QED written by Richard Feynman himself ("QED: The Strange Theory of Light and Matter", for $27.65 at amazon.com; if you are interested in that matter, get it or lend if from your public library soon).

    Basically, the "slow spherical wave" creeping out of a radioactive nucleus is the probability function - does it emit now or later? The actual process of emiting the particle is completely unknown to the observer, and he has no means to determine it in advance. The current theories, QED including, completely side-step this issue. They can tell you with high accuracy about the likelyhood of radioactive processes, and they also can tell you with high accuracy about the energy and the path such an emitted alpha particle has, but they can't tell you more in advance. All these theories even have problems with rapidely changing settings of the experiments, because they simply don't talk about that.

    Time is no more an illusion than space, energy, or force.

It was kinda like stuffing the wrong card in a computer, when you're stickin' those artificial stimulants in your arm. -- Dion, noted computer scientist

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