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Dan T Benedict wrote on May. 9, 2011 @ 21:53 GMT
Anil,
The question: "Could the story of the cosmos have been told sideways rather than from past to future?" is meaningless. We are able to look at the history of the universe only diagonally, since the information that we receive is always tied to both the distance and time of the emitting object. We can only make mostly vague inferences for the states (past, in the spatially present, and future) of all objects in the universe at any specified time other than the time of observation. Unless Craig Callender possesses some omnipotent power, how is he going to get the data he needs for his construction, let alone evolution, of the east-west slice? And, how does he propose to vary time only, without varying space as well?
Dan
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Dan T Benedict replied on May. 9, 2011 @ 22:24 GMT
I suppose he could vary "time only" if he was proposing supercomputer simulations similar to those of Carlos Frenk, etc. But, since Craig is a philosopher, I not exactly sure what he's proposing.
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J.C.N. Smith wrote on May. 9, 2011 @ 22:03 GMT
At the risk of being seen as "old-fashioned" and/or of belaboring what should be obvious, it is worthwhile at the outset of this (or any) discussion to ensure that all participants in the discussion share a common understanding of the terminology involved. So would it be correct to assume that the definition of time being used in this article is the so-called "operational definition of time," i.e., "time is that which is measured by clocks"? And, if so, would it be correct to further assume that a clock is defined as being "a device which measures time"?
If so, let the discussion proceed. If not, please clarify how the terms being discussed in this article differ from the above. Thank you.
Please note that what we refer to as "the flow of time" is nothing more and nothing less than the evolution of the physical universe, as discussed further
here and
here. This view of the flow of time goes a long way toward explaining the various "arrows" of time.
Regards,
jcns
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Eckard Blumschein wrote on May. 9, 2011 @ 22:08 GMT
There is an excellent and almost sufficient book by Zeh on the arrow of time, not in time. "Almost" refers to what I consider the necessary blunt rejection of the belief which was uttered not just in the mentioned letter of condolence.
Claude Shannon expressed more clearly what is wrong with anticipatory tense-less physics: While the past is known, in principle, but can definitely not be changed, the future can be influenced, in principle, but not for sure be predicted.
I do not see this distinction attributable to subjective perception. There are objectively no traces of future events. If we restrict to physics, i.e. to the consideration of measurable data, then there is of course no genuine symmetry and not even asymmetry but a clear-cut one-sidedness. In reality, there is no negative elapsed time, as also is no negative spatial distance.
I do not expect anything of value from Craig Callender's effort as long as he is not ready to accept that the usual notion of time is just an extended abstraction from the unilateral scale of already measurable traces.
On the origin of apparent symmetry I wrote an IEEE paper and three FQXi-essays.
Eckard
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Roy Johnstone wrote on May. 10, 2011 @ 03:15 GMT
I agree with Eckard & J.C.N.
What we call time is generally considered to be that which we measure with clocks, that is, regular physical processes, evolving configurations. The thermodynamic "arrow" is due to the physical laws which enable this motion combined with statistical mechanics (entropy), as per Boltzmann. The causal arrow is I believe due once again to the physical laws , which enable "events" to take place, combined with the constraint of the absolute speed of light.
The end result of the above is that we can only observe processes occurring as governed by the laws of nature in a particular order, including the thermodynamic "statistical" order in a lorentz frame structure. This has nothing to do with a separate entity called "time". I feel that too many people draw a direct correlation between entropy and "time", an example being Sean Carroll in his recent book "From Eternity To Here". If we saw an apple falling upward to re-attach to the tree, we would think it very strange, but we would not think that time was going in reverse. There are many examples of entropy reversing/decreasing due to gravity for instance. I believe that when considered globally, the formation of a star is an entropy lowering process. We would not consider time to be *running backward* when we observed this process!
If an observer were able to "freeze" the universe while remaining conscious, the observer's "psychological arrow" would still give the sense of "duration" and "moving present" due to brain processes, whilst the frozen universe would appear "timeless" only in the sense that there would be no means to "measure" a "time" interval. I believe it is more helpful to think of what we call time as being emergent from these underlying processes purely as a way of " measuring" them, in the same way that temperature "measures" kinetic energy but is not itself fundamental.
Viewed in this way "time" can be thought of as actually being "energy potential" when talking about time operators in our theories and a "magnitude of change" when measured by clocks.
Roy
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B^2 replied on May. 10, 2011 @ 06:30 GMT
"If we saw an apple falling upward to re-attach to the tree, we would think it very strange, but we would not think that time was going in reverse. There are many examples of entropy reversing/decreasing due to gravity for instance."
If you are considering a closed system then you could expend energy to decrease the system's entropy, however, the universe would still have a net gain of entropy increase.
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Roy Johnstone replied on May. 10, 2011 @ 10:58 GMT
"If you are considering a closed system then you could expend energy to decrease the system's entropy, however, the universe would still have a net gain of entropy increase."
The point is though, that the reversal of entropy does not mean a reversal of "time" and the example of the apple is a reversal in the *order* of physical processes not of "time", as we could just as well calibrate our clocks by regular processes where gravity is repulsive for instance.
Your statement I think refers to the "Maxwell's Demon" principle where the energy expended to decrease entropy (or it's information content), must be accounted for as additional entropy and that is right. I don't think that applies in the case of gravity however if you consider the "closed system" to be the universe. Gravitational fields are considered to contain negative energy, hence the cosmic energy equation of state E = 0. When gravity acts to form a star I view that *cosmically* as a lower entropy macrostate. (Which contains the most useful energy that can "do work", the star or the hydrogen gas cloud that formed it?). The energy required to increase the entropy or restore the cosmic entropy number is stored in the star and is slowly radiated back out and eventually fully returned by supernova for example.
I guess it depends on your definition of information and how you quantify the energy content of gravitational fields. Black holes are a whole other case!!
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Pentcho Valev wrote on May. 10, 2011 @ 05:33 GMT
Callender clearly rejects special relativity's conclusions concerning time but these conclusions are RIGOROUSLY DEDUCED from two premises: the principle of relativity and the principle of constancy of the speed of light. If the approach is honest, rejecting the conclusion leads to hinting (at least) at the false premise.
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Eckard Blumschein replied on May. 10, 2011 @ 16:00 GMT
The fallacy is indeed not very obvious. As a schoolboy I was cheated by the teacher who explained Galilei's flawless principle of relativity and attributed it to Einstein. Most textbooks derive the Lorentz transformation from postulated equivalence of all inertial reference frames. Actually, Poincaré's LT predates what Einstein in 1905 on p. 891 called "principle of relativity".
Seemingly a shift in time must not matter. So called laws of physics remain apparently unchanged. I came to the insight that this invariance only holds on the level of abstracted and extrapolated time scale. This usual notion of time must not be confused with the already elapsed time of reality. The latter has peculiarities: It cannot at all be shifted at will, and it only excludes the past. The usual notion of time is in this respect unphysical, and Poincarè's round-trip synchronization includes something that does not yet exist at the moment of consideration.
Hence the first premise is untenable. Yes, if Callender is honest then he has to hint at the false premise.
By the way, mathematicians also considered Cantor's naive set theory rigorously deduced, and Hilbert fought for this belief in a paradise by replacing it with the method of axioms which were ambiguously enough designed as to hide Cantor's mistake and avoid obvious paradoxes.
Eckard
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Pentcho Valev replied on Aug. 10, 2011 @ 14:51 GMT
Eckard Blumschein wrote: "Hence the first premise is untenable. Yes, if Callender is honest then he has to hint at the false premise."
The second premise (Einstein's 1905 constant-speed-of-light postulate) is untenable:
http://www.ccsenet.org/journal/index.php/apr/artic
le/download/10410/7432
Applied Physics Research Vol. 3, No. 1; May 2011, One-Way Light Speed Determination Using the Range Measurement Equation of the GPS, Stephan J. G. Gift
"In particular the one-way determination of light speed using the range measurement equation of the GPS establishes in (7) that a signal sent eastward travels at speed c minus the rotational speed of the Earth v at that latitude giving c - v. The GPS data also shows in (13) that a signal sent westward travels at speed c plus the rotational speed of the Earth v at that latitude giving c plus v."
Pentcho Valev pvalev@yahoo.com
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Eckard Blumschein replied on Aug. 10, 2011 @ 22:01 GMT
Dear Pentcho,
Thank you for your hint to Gift. While I am not familiar with the matter and he did not give error bars, the values 14ns for the distance NY SF and 207ns around the equator might be realistic. Doesn't the ECI frame move during the light travel by several meters? So the c+v westward and the c-v eastward correspond to smaller and enlarged, respectively distances. This reminds me of Foucault's 1852 pendulum. Incidentally Foucault was also the first one who measured c by means of mirrors.
Following Maxwell's theory of light as an electromagnetic wave and in agreement with Van Flandern, I see the GPS data rather a confirmation of c as the speed of light but at odds with SR. I read several books on SR. We cannot deny that high energy accelerator experiments confirmed c as a limit which is to be expected for waves. So I am naively ready to accept electrons as waves but not SR as correct.
Electrodynamics is obviously not covariant under Galilei transform. Incidentally, as Schroeder wrote, Michelson said to Einstein in 1931, he regrets that his work gave rise to the monster of Einstein's theory of relativity (G. Holton, Am. J. Phys. 37,968(1969)
Perhaps, SR cannot be rescued unless one restricts the consideration to closed systems that are free of uncertain or unseen influences which I consider the essence of reality in contrast to theory. This explains why Einstein necessarily admitted to Popper sharing the (abstruse) philosophy of Parmenides, and why he, Hilbert, and others denied any role of the now and even of the arrow of time. Science is still suffering from this implication.
Regards,
Eckard
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amrit wrote on May. 10, 2011 @ 07:10 GMT
This gravity probe B
http://www.physorg.com/news/2011-05-gravity-probe-einstein-t
heories.html
proves following:
-cosmic space is 3D - because all the angles are measured in three directions X,Y,Z
-cosmic space has granular structure - frame dragging
outcome is that time we measure with clocks cannot be the 4th dimension of space:
http://www.physorg.com/news/2011-04-scientists-spacetime-dim
ension.html
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B^2 wrote on May. 10, 2011 @ 07:19 GMT
The human brain has evolved a frontal lobe which is what allows us to care about the future. Most other life only reacts to the stimulus in the present moment. I would like to see a physicist or philosophers take on
entropy/fitness.
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Roy Johnstone wrote on May. 10, 2011 @ 10:27 GMT
I don't think Callander "rejects special relativity's conclusions", only the "block universe" interpretation of them, quite rightly too in my opinion. It is possible to formulate a relativistic spacetime model which evolves. Two notable attempts are George Ellis's "Evolving Block Universe" (which I think is a misnomer and a mistake to use the word "block", perhaps a better word might be "hypersurface"?) and Joy Christian's "Relative Becoming" model. These have the nice advantage of allowing free will also!
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J.C.N. Smith replied on May. 10, 2011 @ 12:06 GMT
"If physics can explain how a causal arrow of time emerges, then biology will do the rest, says Callender."
If the flow of time is viewed (correctly, in my opinion) as being nothing more and nothing less than the evolution of the physical universe (an evolution which is governed by rules that we strive to understand and which we refer to as the laws of physics), then there is no way for "a causal arrow of time" *not* to emerge!
jcns
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Eckard Blumschein replied on May. 11, 2011 @ 08:20 GMT
Dear Roy,
Can a reform of SR and spacetime overcome all paradoxes? To me, the wording Evolving Block Universe by George Ellis illustrates the calamity. It sounds to me like a cruciader in his burka or like communist free market economy. Did Joy Cristian's attempt resolve the problems? Will Lee Smolin achieve the impossible?
I would rather prefer a honest clarification on the fundamental level, no matter what hurting implications are to be expected. When Hilbert defended Cantor's paradise against Brouwer, he also warned of a huge heap of rubble. This was exaggerated.
Regards,
Eckard
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amrit wrote on May. 10, 2011 @ 22:13 GMT
time arrow has no physical existence, time does not point anywhere, time is a numerical order of change
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Lawrence B. Crowell wrote on May. 11, 2011 @ 00:03 GMT
There is a bit of confusion apparent. There are a number of ways of looking at this. Group theory is a good way of looking at this. Relativity is given by the group SO(3,1), which is a set of transformations that can be thought of as rotations. The group SO(3) describes the set of rotations in three dimensional space. The group SO(3,1) has this indefinite metric, where the one separated by a comma reflects the pseudo-Euclidean metric. This group can be decomposed into SU(2)xSU(1,1). SU(2) is related to SO(3) by a double cover, and is a set of elliptical rotations. SU(1,1) is a hyperbolic variant of SU(2). SU(2) contains 3 rotational matrices (often represented by Pauli matrices) and these are pure spatial rotations. SU(1,1) has 3 elements which correspond to Lorenz boosts.
If we think of pushing a spatial manifold in time this can be thought of changing elements that transform under group SU(2) according to elements which construct time and the hyperbolic SU(1,1). We may similarly think of trying to transform a manifold with two spatial dimensions and one of time according to the SU(2) elements. This will result in a noncommutative algebra. This is then equivalent to saying that pushing a slice of space through time is different from pushing a 3-dimensional spacetime through a spatial distance.
Cheers LC
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T H Ray replied on May. 11, 2011 @ 11:39 GMT
Lawrence,
What an excellent, clear and wonderfully concise description of spacetime geometry.
My own model turns the kinematic on its head. That is, instead of assuming that space coordinates construct time, I assume without loss of generality that the time metric constructs space. Then the pseudo-Euclidean metric of SO(3,1) by analytic continuation over n-dimension Euclidean manifolds (n-dimension sphere kissing) accounts for non-commutativity of the metric in d >= 3 -- while preserving classical time reverse symmetry. (For dimensions < 4, we need the complete C* algebra.)
This works all the way from the hyperbolic 2 dimension manifold SU(2) where string theory lives, through n dimensions. It has an important added advantage: because all even dimension spacetimes reduce to 0 + 1, we have the smooth extension of general relativity to n dimensions. Einstein's model -- being finite in time and unbounded in space -- becomes finite in space and unbounded in time, without sacrificing any of the physics we know, and without introducing superfluous assumptions.
I then show from this result, that gravity is entropic over n dimensions, and that our 4 dimension horizon is equivalent to the 10 dimension (9 + 1) limit, due to information loss.
Tom
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J.C.N. Smith replied on May. 11, 2011 @ 13:38 GMT
LC and Tom,
Would it be possible for either (or both) of you to express your ideas about space and time in non-mathematical terms? How do your ideas relate to the human experience of time and space?
In a post in another FQXi blog (Breaking the Universe's Speed Limit) LC wrote: "A[s] for block time being contrary to human experience or intution, those do not really count for much. The non-block time is just a system of spatial geometries which are related to each other by a diffeomorphism group. The notion of time is actually somewhat lost in this picture."
To which I replied: "Regarding whether human experience and intuition count for much, I simultaneously agree with you and disagree with you. Certainly, everyone must agree that human experience and intuition have proven to be extremely fallible. This fact is perfectly illustrated by the pre-Copernican belief that the sun revolves around the Earth.
On the other hand, however, human experience and intuition must count for something, because our empirical observations comprise the very bedrock foundation of science! If we dismiss empirical observations as unimportant (not really counting for much), then what are we left with as the basis for doing science?"
So how do your views of time and space relate to empirical observations which we humans might make, fallible though such observations might be? Which is simply another way of asking, how can we test your concepts experimentally? Are they falsifiable? If so, how?
Thank you.
jcns
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T H Ray replied on May. 11, 2011 @ 17:05 GMT
jcns,
I'll try, though I don't think (and I expect Lawrence will agree) that one can fully appreciate spacetime dynamics without understanding the mathematics. As Lawrence notes, there is more than one way to write the equations that lead to the same physics. We choose our models for their ability to explain current phenomena and to make additional novel predictions.
Classical physics is the domain of human experience. Even our quantum mechanical experiments are designed within classical parameters. What we've learned over the past three centuries or so, though, is that not even classical results are intutive. For example, one cannot intutively connect the falling of an apple from a tree with the falling of the moon toward the Earth without Newtonian mechanics. Even Galilean physics (as I discovered to my surprise recently, by the varied responses to a simple projectile problem) is not immediately intuitive even among people who should know better.
What all classical physics has in common is the mathematics of continuous functions. In other words, Newton's apple does not stop falling at the Earth's surface, but continues falling in principle -- just as the moon's orbit is continuous. Continuous functions are evident to the limit of classical physics, i.e., relativity.
Most of what we know of physics, objectively, is counterintuitive. Lawrence is quite correct that human experience and intuition play an insignificant role.
Quantum mechanical functions are algebraic, i.e., discrete. The basis is the analysis of probabilistic quantum events in a Hilbert space, which means a complex model -- because quantum mechanics does not allow space collapsed to a point (singularity), and the complex plane is fundamentally two-dimensional.
So far as experimental results go, and remembering that all are designed within classical parameters -- I offered a quasi-classical model in my FQXi 2008 essay ("Time counts") in which I constructed a complex analog to Kepler's second law. Because it is based on the (non) conservation of angular momentum using escape velocities between gravitating classical bodies, if each point of spacetime is characterized by a unique escape velocity (it is), the principle is already experimentally verified. What the mathematics shows is a very slight loss of information among bodies.
Point is, to get to these models where Lawrence among others can speak of group theory and noncommutative algebra to model physical phenomena, we have to go through what we know about the classical and quantum worlds and then follow the path where it leads without contradicting previous results. Intuition isn't much help.
Tom
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J.C.N. Smith replied on May. 11, 2011 @ 17:18 GMT
Tom,
Quick reply to thank you for your reply to my question and to let you know I'm pondering what you wrote. More later, assuming I can think of anything resembling cogent to add.
jcns
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J.C.N. Smith replied on May. 12, 2011 @ 12:02 GMT
Tom and LC,
Without claiming that what follows resembles cogent, I'd like to keep this constructive discussion going. If you've read any of my other posts in this or other FQXi blogs you must know that my approach to physics is naive, primitive, and visceral, but I hope not unscientific, in the best sense of that word. I exist in a universe which, statistically, is mostly not hospitable...
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Tom and LC,
Without claiming that what follows resembles cogent, I'd like to keep this constructive discussion going. If you've read any of my other posts in this or other FQXi blogs you must know that my approach to physics is naive, primitive, and visceral, but I hope not unscientific, in the best sense of that word. I exist in a universe which, statistically, is mostly not hospitable to fragile life forms such as myself. Understanding physics, therefore, is, for me, a matter of survival as well as a matter of great intellectual curiosity and fascination.
The universe in which I find myself is extremely dynamical. There are lots of things in motion, cars, clouds, airplanes, planets, galaxies, occasionally (and frighteningly, during earthquakes and tornados) even pieces of buildings, trees, etc. If some of these objects were to collide with me it could be fatal at worst and uncomfortable at best. Again, understanding how this all works (i.e., understanding the laws of physics which appear to govern it all) on a visceral, intuitive level is essential to survival.
Tom, you wrote "Point is, to get to these models where Lawrence among others can speak of group theory and noncommutative algebra to model physical phenomena, we have to go through what we know about the classical and quantum worlds and then follow the path where it leads without contradicting previous results. Intuition isn't much help." My reply is that unless these models are taken to be purely academic, mathematical exercises they ultimately must tell us something of practical value about the universe in which we exist. It is this "something" which I'm trying to tease out of our discussion. How will these models ultimately allow me to improve my chances of survival?
Without a doubt, mathematical models play an important role in physics. At some point, however, mathematical models must somehow come into contact with empirical observations if they are to be of any real value, in my opinion. Granted, human experience and intuition are known to be extremely fallible, but that not withstanding they are still our only real basis for doing science (as opposed to pure mathematics).
Mathematicians presumably could develop a model of the Ptolemaic picture of the universe as readily as they could develop a model of the post-Copernican picture. We then could talk about these two models in purely mathematical terms ad nauseam, but it is also satisfying to be able to talk also about the fact that one model has the sun revolving around the Earth whereas the other model has the Earth revolving around the sun while simultaneously rotating on its axis. One model ultimately is more useful than the other, despite the fact that human intuition accepted the less useful model as being "obviously" true for centuries.
As repeatedly noted elsewhere in these blogs, I'm a huge advocate of zeroing in on better and better paradigms. And I've long been concerned that the mainstream, prevailing paradigm for the fundamental nature of time is lacking. Not "wrong" perhaps, but lacking, or incomplete. Inasmuch as "time" plays such a central and crucial role in physics I believe it's worthwhile being certain that we have this paradigm nailed down as correct as possible.
Unless I'm mistaken (please correct me if I am), the prevailing paradigm for the nature of time may be summarized by the so-called "operational" definition, i.e., "time is that which is measured by clocks." Clocks are then typically defined in some sort of slippery way as being devices which measure time by way of some sort of "regular motion," but it is never made perfectly clear how one would know whether motion was "regular" or not without resorting to the use of a clock. I'm not saying that this is "wrong" per se, but only that it seems, at best, incomplete. This view of time apparently leads logically to concepts such as block time.
In some of my essays such as 'Time: Illusion and Reality,' I've tried to suggest another paradigm, another way of looking at the nature of time, which, unfortunately, is also, in and of itself, incomplete I fear. In this way of looking at time our dynamical universe is the clock. Different physical configurations of the universe define, and are identically equivalent to, different particular times. This view does not allow for block time, and it makes a "causal arrow of time" an inevitability. It further rules out time travel (at least of the variety portrayed in science fiction literature).
Lawrence actually appeared to key in on this view in one of his posts to the article on 'Breaking the Universe's Speed Limit' when he wrote, "A[s] for block time being contrary to human experience or intution, those do not really count for much. The non-block time is just a system of spatial geometries which are related to each other by a diffeomorphism group. The notion of time is actually somewhat lost in this picture." Yes, in my view non-block time is indeed a system of spatial geometries! Exactly! But as he points out, the conventional notion of time is somewhat lost in this picture. And this may be where this paradigm is incomplete.
I can't help thinking that if some very clever person could somehow meld these two views of time the resulting paradigm might offer a more useful way of looking at the universe than any previously proposed. Unfortunately, I do not know how to accomplish this melding, but I sense that it would not be easy.
Apologies for rattling on for so long.
Regards,
jcns
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T H Ray replied on May. 12, 2011 @ 17:19 GMT
JCNS,
You wrote, "If you've read any of my other posts in this or other FQXi blogs you must know that my approach to physics is naive, primitive, and visceral, but I hope not unscientific, in the best sense of that word."
Sure.
"I exist in a universe which, statistically, is mostly not hospitable to fragile life forms such as myself. Understanding physics, therefore, is, for...
view entire post
JCNS,
You wrote, "If you've read any of my other posts in this or other FQXi blogs you must know that my approach to physics is naive, primitive, and visceral, but I hope not unscientific, in the best sense of that word."
Sure.
"I exist in a universe which, statistically, is mostly not hospitable to fragile life forms such as myself. Understanding physics, therefore, is, for me, a matter of survival as well as a matter of great intellectual curiosity and fascination."
I agree. I touched on this in my 2010 FQXi essay. "When one calculates
outcomes from a field of infinite parameters, the great majority lead an organism to extinction. Yet conscious creatures play with loaded dice; 'good' and 'bad' choices, assuming that all strategies are rational, i.e., survival-based, depend on having at least one good choice independent of all environmental influences considered as a continuum. E.g., if a one-celled creature needs light to survive, it either has the motive ability to seek
a light source in order to 'be,' or it ceases to be when the light goes away."
We're fragile only when we don't have options. More consciousness creates more survival options and more robust life. We're all complex systems of cooperating cells.
"The universe in which I find myself is extremely dynamical. There are lots of things in motion, cars, clouds, airplanes, planets, galaxies, occasionally (and frighteningly, during earthquakes and tornados) even pieces of buildings, trees, etc. If some of these objects were to collide with me it could be fatal at worst and uncomfortable at best. Again, understanding how this all works (i.e., understanding the laws of physics which appear to govern it all) on a visceral, intuitive level is essential to survival."
Absolutely.
"Tom, you wrote 'Point is, to get to these models where Lawrence among others can speak of group theory and noncommutative algebra to model physical phenomena, we have to go through what we know about the classical and quantum worlds and then follow the path where it leads without contradicting previous results. Intuition isn't much help.' My reply is that unless these models are taken to be purely academic, mathematical exercises they ultimately must tell us something of practical value about the universe in which we exist. It is this 'something' which I'm trying to tease out of our discussion. How will these models ultimately allow me to improve my chances of survival?"
Does electrical power improve your chances of survival? There's a story, maybe apocryphal but surely instructive, that a matron upon being introduced to Michael Faraday, asked of what use are his discoveries. Faraday supposedly replied, "Madame, of what use is a newborn baby?"
"Without a doubt, mathematical models play an important role in physics. At some point, however, mathematical models must somehow come into contact with empirical observations if they are to be of any real value, in my opinion. Granted, human experience and intuition are known to be extremely fallible, but that not withstanding they are still our only real basis for doing science (as opposed to pure mathematics)."
Actually, experience and intuition are of little use in doing science. Most of what we know, objectively, is counterintuitive. As Einsten said, "Imagination is more important than knowledge."
"Mathematicians presumably could develop a model of the Ptolemaic picture of the universe as readily as they could develop a model of the post-Copernican picture."
True.
"We then could talk about these two models in purely mathematical terms ad nauseam, but it is also satisfying to be able to talk also about the fact that one model has the sun revolving around the Earth whereas the other model has the Earth revolving around the sun while simultaneously rotating on its axis. One model ultimately is more useful than the other, despite the fact that human intuition accepted the less useful model as being "obviously" true for centuries."
They accepted it because of their quasi-religious philosophy that the circle represents perfection. A perfect universe, therefore, had to incorporate perfectly circular orbits (and they almost are, in fact). We should be wary of trying to impose religion or philosophy on science.
"As repeatedly noted elsewhere in these blogs, I'm a huge advocate of zeroing in on better and better paradigms. And I've long been concerned that the mainstream, prevailing paradigm for the fundamental nature of time is lacking. Not 'wrong' perhaps, but lacking, or incomplete. Inasmuch as 'time' plays such a central and crucial role in physics I believe it's worthwhile being certain that we have this paradigm nailed down as correct as possible."
How certain can we be of anything?
"Unless I'm mistaken (please correct me if I am), the prevailing paradigm for the nature of time may be summarized by the so-called 'operational' definition, i.e., 'time is that which is measured by clocks.' Clocks are then typically defined in some sort of slippery way as being devices which measure time by way of some sort of 'regular motion,' but it is never made perfectly clear how one would know whether motion was 'regular' or not without resorting to the use of a clock. I'm not saying that this is 'wrong' per se, but only that it seems, at best, incomplete. This view of time apparently leads logically to concepts such as block time."
Not regular motion -- regular physical processes. Motion is measured change in relative position among mass points. A physical process, however, need not involve classical motion. I won't get into a long discussion of the nature of time, about which I've written extensively. If you are interested, you can find my views
here .
"In some of my essays such as 'Time: Illusion and Reality,' I've tried to suggest another paradigm, another way of looking at the nature of time, which, unfortunately, is also, in and of itself, incomplete I fear. In this way of looking at time our dynamical universe is the clock. Different physical configurations of the universe define, and are identically equivalent to, different particular times. This view does not allow for block time, and it makes a 'causal arrow of time' an inevitability. It further rules out time travel (at least of the variety portrayed in science fiction literature)."
Interesting. I'd say go for it, and build a mathematical model to accompany.
"Lawrence actually appeared to key in on this view in one of his posts to the article on 'Breaking the Universe's Speed Limit' when he wrote, "A[s] for block time being contrary to human experience or intution, those do not really count for much. The non-block time is just a system of spatial geometries which are related to each other by a diffeomorphism group. The notion of time is actually somewhat lost in this picture." Yes, in my view non-block time is indeed a system of spatial geometries! Exactly! But as he points out, the conventional notion of time is somewhat lost in this picture. And this may be where this paradigm is incomplete.
I can't help thinking that if some very clever person could somehow meld these two views of time the resulting paradigm might offer a more useful way of looking at the universe than any previously proposed. Unfortunately, I do not know how to accomplish this melding, but I sense that it would not be easy."
Easy or not, it's worthwhile. Google for Gerard 't Hooft's advice on how to be a theoretical physcist. Good list of prerequisites to study.
"Apologies for rattling on for so long."
Rattling makes music, too. :-)
Tom
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J.C.N. Smith replied on May. 13, 2011 @ 12:45 GMT
Tom,
Thank you for your thorough reply. Much appreciated. You have raised some interesting points.
To reverse the order of things somewhat, I've studied 't Hooft's advice to theoretical physicists, along with the Baez and Siegel "indices" and could not agree more. Questioning established wisdom is something which one must do with great caution and trepidation. Established wisdom...
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Tom,
Thank you for your thorough reply. Much appreciated. You have raised some interesting points.
To reverse the order of things somewhat, I've studied 't Hooft's advice to theoretical physicists, along with the Baez and Siegel "indices" and could not agree more. Questioning established wisdom is something which one must do with great caution and trepidation. Established wisdom is established for a reason, albeit not always a correct reason, as was somewhat rudely pointed out by Copernicus.
With regard to questioning established wisdom about the nature of time I'm encouraged by evidence that well respected scientists can be found among those doing so. In his book 'The Trouble With Physics,' Lee Smolin wrote, "More and more, I have the feeling that quantum theory and general relativity are both deeply wrong about the nature of time. It is not enough to combine them. There is a deeper problem, perhaps going back to the origin of physics." (p. 256) This is precisely the point I have made explicitly in my essay 'Time: Illusion and Reality,' and I have discussed there how I suspect the problem may have arisen.
In the context of zeroing in on optimum paradigms you asked "How certain can we be of anything?" Excellent question. It's my own view that paradigms should hold sway only for as long as they represent the most useful explanation for observed phenomena. Unless competing paradigms are fairly considered and evaluated, however, the process of evolution from one paradigm to another, hopefully better one will be impeded.
Regarding my proposed paradigm for the nature of time you wrote "Interesting. I'd say go for it, and build a mathematical model to accompany." I'd love nothing better, Tom, but not being a skilled physicist or mathematician I'm not in an ideal position to do so. I spent my most productive years pursuing another line of work, but for well over 50 years I have followed the course of this ongoing discussion in the popular literature, absorbing the thinking of Barbour, Carroll, Davies, Deutsch, Feynman, Greene, Hawking, Kuhn, and Smolin, to name but a few. My best hope is that one of these luminaries or some other will someday see fit to explore the view which I've outlined in purely qualitative terms in essays such as those
here and
here. Having studied what others have said on the topic, I continue to believe that my ideas have merit, and that they add something worthwhile to what others have already said. It's a bit of a frustrating position in which to find oneself. It's for this reason that I deeply appreciate forums such as FQXi in which ideas may be aired and discussed.
Speaking of which, I've begun reading your essays for which you so kindly provided a link. I can already see that they will be slow going for me, but I will do my best to understand the points you are trying to make in them.
Thank you again for engaging on this.
jcns
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T H Ray replied on May. 13, 2011 @ 18:13 GMT
jcns,
The nature of time remains an unsettled (and often, unsettling) question. I've read your papers, and with your implied permission I'd like to offer a couple of quick observations:
You attribute to Feynman the observation that measures of space and time units are interchangeable. This concept actually originates with Minkowski and Einstein, where time is continuous with space...
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jcns,
The nature of time remains an unsettled (and often, unsettling) question. I've read your papers, and with your implied permission I'd like to offer a couple of quick observations:
You attribute to Feynman the observation that measures of space and time units are interchangeable. This concept actually originates with Minkowski and Einstein, where time is continuous with space in a field (metric tensor). Feynman's contribution is to convert this continuous-function model to an algebraic, i.e., discrete, model -- which is a natural step for Feynman the particle physicist to take, because he doesn't have to worry about singularities forming in particle interactions where space and time directions are orthogonal (quantum unitarity). Then another "Einstein" in the form of Stephen Hawking comes along and further extends the idea by reuniting it with relativity; i.e., because the quantum model is 2-dimensional, one can show by complex analysis that relativity avoids the singularity at the extreme of black hole thermodynamics, because in the imaginary part of the complex sphere, time is indistinguishable from space.
Are you getting the idea of how important it is to understand the mathematics in order to understand the physics? As Yogi Berra said, "If you don't know where you're going, you might end up somewhere else."
Another important application of mathematics is to the classical dynamic of time reverse symmetry. Don't listen to the crackpots who insist that time reversal is impossible and physicsts are just stupid -- time conservation is critical to classical physics. That doesn't mean that we witness broken teacups reassemble themselves and hop back up on the table, or that we are ever likely to. It means that the laws of physics, and its equations, work as well in reverse as they do forward in time; e.g., the Earth rotates in one direction and orbits in one direction. The physics would not change if the directions were reversed. Yes, there are esoteric theories not forbidden by general relativity where time travel can happen under high energies and special conditions. To everyday physics, they don't matter and classical scale time travel probably is impossible.
I suppose I might as well try and summarize my own research on the subject of time, if I can. In a nutshell, _processes_ are reversible in time, but _events_ are not. What I mean is that time has a specifically physical definition: "n-dimension infinitely orientable metric on self-avoiding random walk." You can read my ICCS 2006 paper to see how and why I arrived at that definition. As a consequence, detailed in ICCS 2006 and later in my "time barrier" paper, it follows straightforwardly that at a specific calculated limit a continuous curve is exchanged for a discrete point, with analytic continuation and dissipation over n-dimensional manifolds, supported by a Euclidean sphere kissing model. That exchange constitutes a discrete event emergent from a continuous process. Ultimately, gravity is identified with information entropy (as is also the case with the Jacobson-Verlinde model), with time dissipation asymptotic to length 1. My model extends general relativity which is finite in time and unbounded in space, to one which is finite in space and unbounded in time.
Point is, there certainly are theories of time that meet your criterion for giving a specific definition (actually, most do, but some definitions are well hidden and have to be abstracted from context). Julian Barbour is another theorist who is quite up front and specific with his definition, identifying time with the least action principle, as a non-physical abstraction. (Least action also figures into my theory, in a different way.)
Good luck to you in your own journey! FWIW, I'd say you've started well.
Best,
Tom
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Eckard Blumschein replied on May. 13, 2011 @ 23:04 GMT
Tom,
Already the word process should tell you that something that pro-cedes (goes ahead) is in reality not reversible. You are reiterating an old half-truth: "the laws of physics, and its equations, work as well in reverse as they do forward in time ... The physics would not change if the directions were reversed."
Well, in particular differential equations are likewise valid for both directions of time. They are, however, not the primary relationships but they were abstracted from the latter at the cost of lost embedding into the causal structure of reality. Is there anything absolutely isolated in the world? Is there any absolutely circular process? I only see spirals instead of circles. Absolutely closed systems are merely idealizations. I like them on condition they are not misused as to derive nonsensical conclusions.
Those who are ready to understand their own tools do not have problems with all practical important aspects of the notion time. Time just becomes an enigma to those who are in a similar situation as someone who made a mistake, tries to hide it, and gets increasing trouble to justify his excuses by exotic fabrications:
"n-dimension infinitely orientable metric on self-avoiding random walk."
"... at a specific calculated limit a continuous curve is exchanged for a discrete point, with analytic continuation and dissipation over n-dimensional manifolds, supported by a Euclidean sphere kissing model. That exchange constitutes a discrete event emergent from a continuous process."
Self-avoiding sounds funny. Dissipation does not necessarily relate to time and money since you used it in a strictly mathematical sense.
Hopefully you are aware why use of complex calculus needs analytic continuation.
If I recall correctly, items that relate to less well known names like Euclid begin with a capital letter while names that are so famous that they are well known to everybody like kissing do not need this profanity.
You are certainly proud of extending "general relativity which is finite in time and unbounded in space, to one which is finite in space and unbounded in time".
Congratulations.
Because you already refused to defend SR, I should perhaps finish our discussion.
Regards,
Eckard
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J.C.N. Smith replied on May. 14, 2011 @ 12:50 GMT
Tom,
Thank you for reading my essays and for your encouraging words.
In one way or another we are all fellow travelers and collaborators doing our best to understand this amazing universe in which we find ourselves. Progress can be frustratingly slow, halting, and arduous, but I think we're all encouraged by a deep-seated belief in Einstein's observation that "the most incomprehensible thing about the universe is its comprehensibility." Persistence will not go forever unrewarded, and in some sense the journey itself is, at least for some of us, its own reward.
Good luck to you in your journey, too.
Best,
jcns
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T H Ray replied on May. 16, 2011 @ 12:25 GMT
jcns,
(is that how you wish to be addressed -- "jcns"?)
Your use of one of my favorite Einstein quotes compelled me to scan-read the source of it, Einstein's 1936 essay,
Physics & Reality , which I originally read many years ago and several times since. It is a beautifully clear and meaningful description of scientific method, and reads as if it could have been written today.
Addressing the still unresolved problem of unifying relativity with quantum mechanics (repeated later almost verbatim in an appendix to his posthumnously published book The Meaning Relativity), Einstein wrote:
"To be sure, it has been pointed out that the introduction of a space-time continuum may be considered as contrary to nature in view of the molecular structure of everything which happens on a small scale. It is maintained that perhaps the success of the Heisenberg method points to a purely algebraical method of description of nature, that is to the elimination of continuous functions from physics. Then, however, we must also give up, by principle, the space-time continuum. It is not unimaginable that human ingenuity will some day find methods which will make it possible to proceed along such a path. At the present time, however, such a program looks like an attempt to breathe in empty space."
Now that we know that "no space is empty of field" even beyond the Minkowski space, quantum field theory and the algebraic techniques incorporated in the QFT extension called string theory, bring us ever closer to Einstein's goal of preserving continuous functions (the physics of experience, as his essay makes clear) while explaining the discrete phenomena that are otherwise "incomprehensible" to our experience.
Best,
Tom
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J.C.N. Smith replied on May. 16, 2011 @ 16:03 GMT
Tom,
Many thanks for the link to Einstein's essay. To say that it is germane to the topics we've been discussing here at FQXi would be a gross understatement. Especially fascinating to me (of course) is his discussion of clocks and time, but the whole essay is fascinating.
Regarding a form of address, jcns works admirably, thanks; I'm not big on formality.
Best,
jcns
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Pentcho Valev wrote on May. 11, 2011 @ 07:41 GMT
Eckard Blumschein wrote: "Yes, if Callender is honest then he has to hint at the false premise."
Impossible. George Orwell calls this "crimestop":
http://www.liferesearchuniversal.com/1984-17
George Orwell: "Crimestop means the faculty of stopping short, as though by instinct, at the threshold of any dangerous thought. It includes the power of not grasping analogies, of failing to perceive logical errors, of misunderstanding the simplest arguments if they are inimical to Ingsoc, and of being bored or repelled by any train of thought which is capable of leading in a heretical direction. Crimestop, in short, means protective stupidity."
Pentcho Valev pvalev@yahoo.com
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Eckard Blumschein replied on May. 11, 2011 @ 14:29 GMT
Dear Pentcho,
It took centuries for the Vatican to rehabilitate Galileo Galilei who had to recant relativity. I hope the community of physicists will able to eventually admit the correctness of his following insights:
- Salviati: The relations smaller, equal to, and larger do not hold for entities of infinite quantities.
In other words, infinity is a property, not an exhaustible quantity.
Accordingly we may distinguish between potentially infinite and actually uncountable, but Cantor's cardinality has no logical basis. Already aleph_2 has proven nonsense without any application.
- Galileo Galilei made a careful study of the laws of falling objects. He realized that the velocity of any object relates to a chosen point of reference. Galilei as well as Newton, who was born in the year 1642 when Galilei died, assumed the space unchanging and the universe like a big clock. The belonging addition of velocities and ubiquitous synchronism of remote processes are foundational in technology.
So called relativism has been based on the not always appropriate suggestion to synchronize remote clocks A and B by means of a round-trip measurement. This works well as long as there is no motion between clock A and clock B because in this case the measurement is subject to the Doppler effect to be considered. Poincarè's round-trip method averages the past and the future (with respect to the moment of reflection) time of flight. As a first resulting paradox, the Lorentz transformation is independent of the sign of velocity.
I see stupidity behind the reasoning of those who were misled to ignore Galilei. Many mathematician from Dedekind and Cantor to Cohen agreed on that there must be more real than rational numbers because the latter are a subset of the reals. Most physicists were not ready to accept that the Michelson-Morley did not confirm the existence of an ether.
Regards,
Eckard
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Re_Ality (Facebook) wrote on May. 11, 2011 @ 08:21 GMT
The question as to why the 'arrow of time' is one directional is very easy to answer, if one understands what reality and 'time' actually is, which I would suggest is a very good start point.
Since light travels at a speed that does not vary from one wave to the next, then each state of any given entity, can only be seen (by human and non-human)in the sequence of change in which it occurred. Otherwise you would see flowers blooming before the buds had formed, etc. This statement works for any medium that coneys experiential information to our senses. It also works if the speed of light has changed historically (that just makes calculation of the original state manifested in the observation a lot more difficult). Our sense of 'time' is actually a perception of real change. And yes we have instigated a man-made measuring system called time, but don't let that confuse the underlying issue, which is about change in reality.
Paul Reed
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amrit wrote on May. 11, 2011 @ 19:26 GMT
Time is an epiphenomenon of change
Change is the fundamental property of material world. Time that we measure with clocks is the numerical order of change, i.e. motion in space. In physical world time exists as the numerical order of change in space. In physics time is a mathematical dimension used for description of change in material world. It is an utter misunderstanding to think time is part of space and change run in time. On the contrary: time is an epiphenomena of change, time we measure with clocks is the numerical order of change.
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Re Ality (Facebook) replied on May. 12, 2011 @ 08:59 GMT
Amrit
Correct, just about.
Love the word epiphenomenon, the best I could come up with was conceptualisation.
Paul Reed
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Robert L. Oldershaw wrote on May. 12, 2011 @ 22:03 GMT
How about:
Physical causality only operates in one temporal direction: crack the egg, mix it up with a bit of milk, cook it, eat it.
It can NEVER go the other way.
Wait for an eternity - the eggs won't unscramble.
Thus, the direction of physical causality defines the temporal order.
End of story.
Robert L. Oldershaw
...//www3.amherst.edu/~rloldershaw
Discrete Scale Relativity; Fractal Cosmology
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Eckard Blumschein replied on May. 13, 2011 @ 07:20 GMT
Dear Robert Oldershaw,
Yes, there is no reason to doubt that in any PROcess time lapses from cause to effect.
You quoted Galileo Galilei who mentioned "honest reasoning". Doesn't such honesty demand to realize that a tense-less physics with symmetry between past and future cannot be correct?
I didn't expect you supporting Einsteinian relativity. Having looked at your paper on "Discrete Scale Relativity", which exclusively refers to General Relativity, I do not exclude that you are aware of the intrinsic link between the tacit denial of the arrow of causality in SR and the usual notion of spacetime while the GR might be nonetheless justified to some extent.
When I was a schoolboy, I was told that SR might be correct while GR is questionable. Could it be the other way round?
Regards,
Eckard
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Eckard Blumschein replied on May. 16, 2011 @ 22:48 GMT
Dear Robert Oldershaw,
Did you overlook my question? I am curious.
Regards,
Eckard
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Marcel-Marie LeBel wrote on May. 15, 2011 @ 04:15 GMT
2011-05-14
Time does exist and is a local property as can be seen by the GPS corrections required to match satellites and Earth’s time rates..
I met Callender in 2004 ( http://www.spacetimesociety.org/conferences/2004/attendees.h
tml ) at the (first) spacetime conference in Montreal. His presentation was much about the biophysical perception of time as an argument against real time. I think it was the usual mix-up between two different domains. We judge all things by what we believe to be true. But unless one defines what truth means, this judgement is or can be really wrong. Truth is an absence of choice. Since we have no choice but to experience time in our reality ... it is true! Past, present and future is our lot. But physics shows us a bit of what the underlying universe is really like. And it is true for the underlying reality. Why do we always feel compelled to compare the truths of our very subjective reality with the truths that physics gives us about the underlying reality? They are two different and non-comparable domains! There is no need for comparison and there is no comparison possible.
Craig is doing physics to answer philosophical questions. He is not about to get a straight answer...
Marcel,
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Eckard Blumschein replied on May. 15, 2011 @ 08:18 GMT
Marcel,
Craig wrote: "There is no special now, just as there’s no special here."
The reason for me to deal with time was a practical one. What you are calling physics is obviously rather awkward if compared with audition. Should we really absolutely deny a better physics? I prefer purifying mathematical foundations of physics from inappropriate ontology. Let me claim: Physics must obey causal thinking in terms of here and now.
While negative distance is unconceivable we must not infer that imaginary numbers are useless. On the contrary, they are often superior. However, every scientist should know how to correctly interpret mathematics. I see a main mistake in the assumption of closed systems. We are not forced to believe in Gods, the Big Bang, Spacetime, Aleph_2, Quantum Computing, Antiworlds, etc.
We might be better off humbly accepting that there are several questions that cannot be reasonably answered at least for now. Let's rather listen to the way we listen and not shy back from logical consequences.
Regards,
Eckard
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John Merryman wrote on May. 15, 2011 @ 16:59 GMT
To Tom and Lawrence,
What do you perceive to be "intuition?"
It seems to me that while your understanding of math might be 21st century, your understanding of neurology is not. Intuition is simply that store of non-linear knowledge our minds can access without having to consciously consider it. I suspect you both have great stores of knowledge which frame your understanding of the world. That is your intuition. Someone in another profession, or another time would have different stores of knowledge and so would have different responses to new situations, or information.
Basically what you are saying is that anyone who does not share your understanding of reality is naive and shallow, but that's okay, because they just don't know how dumb they are.
I live in Baltimore, which is home to Johns Hopkins University, a prominent medical school, as well as being notable in other fields. Occasionally the local public radio station invites faculty on to discuss their areas of expertise. Some years ago the host had a neurologist on, discussing the mind/brain relationship. I happened to have the time to call and made the point I frequently make here about time. I described it by saying that if you have two physical objects and they hit each other, it creates an event. While the objects go from past events to future ones, the events go from being in the future to being in the past. The relationship between the brain and the mind is that while the brain is a physical object that goes from past events to future ones, the mind is a record of these events which are going in the opposite direction. His immediate response was, "That's deep." Then he started to launch into a description of how physics explains time as part of four dimensional spacetime. At which point the host cut us both off and went onto the next caller.
I suppose that by your reckoning, this neurologist's initial response would be "naive intuition."
My problem is; Why does the discipline of physics have the right to totally dominate the discussion of the nature of reality, insisting the rest of us are basically dumb, then project these vaunted "non-intuitive" mathematical models into multiworlds, wormholes, m theory, inflationary cosmology, multiverses and various other nonsense? Then if anyone questions what they are doing, the response is some form of, "Well, you just don't understand the math. Here, take this conceptual Rubik's Cube and when you figure it out, then you have the right to discuss reality."
Not to be rude, but to paraphrase the French anti-establishment economics, it's "Autistic Physics."
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T H Ray replied on May. 15, 2011 @ 17:59 GMT
"Why does the discipline of physics have the right to totally dominate the discussion of the nature of reality ... "
Why would one come to a physics site to try and argue that it doesn't?
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John Merryman replied on May. 16, 2011 @ 04:44 GMT
Tom,
I suppose I could have worded that a little more effectively. Though I don't suppose I have to explain my thoughts on the subject to you, as you are likely aware of my views.
That is a rather selective observation though. Does physics describe reality as effectively as possible, or have various schools of thought monopolized the conversation to the point that any idea which supports their models, no matter how outlandish, are considered valid proposals. While any idea which questions those models, no matter how rational, is considered quackery?
If evidence of galaxies at least as old as the presumed age of the universe, 13.7 billion years, was discovered, would you be more likely to consider the possibility of fundamental flaws in the entire concept of a temporally finite universe, or would you accept whatever conceptual patch is applied to this "anomaly" as a viable solution?
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T H Ray replied on May. 16, 2011 @ 10:35 GMT
John,
If you're right, why do you care who considers it "quackery?"
Rational, as in scientific rationalism, is another matter. The models you criticize have exact correspondence to physical phenomena (not necessarily 1 to 1 correspondence as a wholly deterministic theory requires) and so are rational, whether you understand the correspondence or not. It is not rational to imply that such models are merely "conceptual patches."
I don't know why you ask _me_ about the possibility of a temporally finite universe being an incomplete model. I've already rigorously argued that Einstein's finite but unbounded (finite in time and unbounded in space) model can be extended to one that is finite in space and unbounded in time. Galaxies more distant than the present esitmated age would not falsify the theory, however.
Tom
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Eckard Blumschein replied on May. 16, 2011 @ 13:32 GMT
Tom Ray wrote to John Merryman: "The models ["multiworlds, wormholes, m theory, inflationary cosmology, multiverses and various other nonsense"] you criticize have exact correspondence to physical phenomena (not necessarily 1 to 1 correspondence as a wholly deterministic theory requires) and so are rational, whether you understand the correspondence or not. It is not rational to imply that such models are merely "conceptual patches."
There is one always foundational question: Are we sure that we were told something correct? My personal experience made me aware of some indications of something possibly wrong. When I asked a professor of mathematics for an explanation of something rather illogical, he said with resignation that Weierstrass and Cantor decided to arbitrarily change mathematics. Having thoroughly dealt with the matter since then, I recently found confirmed by David Joyce what I consider a foundational misconception.
It is not my style to call for instance aleph_2 nonsense. However, I should be allowed to persistently stress that it did not find any tangible confirmation within more than a hundred years, neither logically nor by reasonable application.
The same seems to be true for other utterly paradox tenets. I am not at all impressed by the many evidences, even mathematical ones for the existence of God. Likewise, the methods of agitation for Lorentz transformation and its outgrows reminds me of meanwhile down-broken gospels.
I looked into Bohm's "The Special Theory of Relativity" and found on p. 107: "nonrelativistic theories of electromagnetic phenomena can be made to give the same results as relativistic theories". Somewhere Bohm mentioned Myon decay, an argument that I cannot refute because I am not at all able to understand the perhaps sophisticated procedure of measurement. After the community tolerated Nimtz who measured "evidence" for propagation of signals with a speed in excess of c, I do not trust in similar evidences. To me counts whether or not quantum computers work like promised, Higgs and SUSY were found, etc.
Eckard
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John Merryman replied on May. 16, 2011 @ 17:39 GMT
Tom,
Even Paul Steinhardt is starting to walk back Inflation, per the feature article in last month's SciAm, because it creates more problem than it solves. How many Hail Marys does it take to make that a "1 to 1 correspondence?"
Dark Energy isn't even a patch. Essentially it's a contract put out for whomever can resolve the rather enormous lack of correspondence between theory and observation. How can a theory ever be considered wrong, if every failed prediction is simply considered evidence of some undiscovered property? That's not science, that's religion. True Believers remain undaunted in the face of adversity.
Do you even know what intuition is, since you seem view it in such a negative light?
When you are sitting around in the evening, with various ideas, theories, equations, etc. running through your thoughts and suddenly a connection occurs to you; That is insight. Then the mind starts considering it and the scales of accumulated knowledge either tilt to the opinion that it is worth further consideration, or that it's just a fluke of the imagination and you dismiss it. That is intuition.
When Einstein was sitting on that train and had a flash of insight as to how the speed of light maintains consistency for all observers, due to the mediation of distance and duration, it was his intuition, his accumulated knowledge, which suggested it was an idea worth pursuing.
When I suggested to that neurologist that the distinction between the mind and the brain could be due to the function of time, it was enough of an insight to him that he recognized it as such. Then his years of formal eduction kicked in and his intuition told him that time is part of a four dimensional geometry and a neurological illusion.
Why is it that the insights of an early 20th century physicist outweigh what is an insight to an early 21st century neurologist? Is it simply because Physics Rules? Even though this mashup of space and time facilitates all number of conceptual nonsense?
So you are right; Sometimes our intuition can fail massively, but we should understand why, before we start peaching the gospel, because our sense of what is right and what is wrong is a function of that very intuition.
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T H Ray replied on May. 16, 2011 @ 18:11 GMT
"When Einstein was sitting on that train and had a flash of insight as to how the speed of light maintains consistency for all observers, due to the mediation of distance and duration, it was his intuition, his accumulated knowledge, which suggested it was an idea worth pursuing."
Except for the fact that that isn't what he intuited.
If you knew the classical physics that preceded Einstein's insight into relativity, as he knew it, you wouldn't have to imagine stuff by which you predict the demise of physics.
Tom
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Lawrence B. Crowell replied on May. 16, 2011 @ 22:03 GMT
Aargh, there is no such discrepancy between theory and measurement. The de Sitter conformal expansion factor describes inflation. What is not known is the nature of the quantum vacuum or equivalently the quantum states of the universe which make up this factor. This is why it is called dark energy. To understand this requires a complete theory of quantum gravity, which as yet does not exist. However, the existence of this dark energy is well documented in the data. During the so called inflationary period, where the universe exponentially expanded much more rapidly, the vacuum was set at a much higher value. Now the vacuum is in some broken configuration at a much lower energy. This residual energy is what drives the current exponential expansion of the universe.
Cheers LC
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Eckard Blumschein replied on May. 16, 2011 @ 22:36 GMT
John,
You wrote "the brain is a physical object that goes from past events to future ones." Is this correct?
I see prediction, preparation, planning, and other anticipations of future merely a combining extrapolation on a sound physiological basis that does not reverse causality. An anticipated picture of future events is never already future reality, no matter how likely it will come true.
Tom,
You wrote "classical physics that preceded Einstein's insight into relativity". Wasn't relativity of motion clearly understood by Galileo Galilei and Isaak Newton while Poincaré's unjustified round-trip synchronization implied a possibility to interpret the so far ad hoc postulated as to justify the idea of an ether Lorentz transformation in a rather speculative manner? In Germany, Einstein was made accepted by Max Planck, and he did not get a Nobel price awarded for his theory of "relativity". Instead of celebrating Minkowski's spacetime as an insight, we should rather look for non-paradox alternatives that are in agreement with reality. So far it looks to me as if Galilean physics is still correct, not just as an approximation for low speed.
By the way, doesn't Galilean relativity mean that I cannot at all attribute a speed to anything unless a reference has been chosen? The speed of sound in air refers to the air. What does the speed of light refer to?
Ritz considered light like a bullet referring to the emitting source. I can definitely not expect a single observer like myself central to reality. Let's consider light from the sun approaching me. I do not see any reason to assume that I am able to change its speed by moving myself towards or away from the sun. In these cases I merely expect the observed wavelength changed by the Doppler effect. I do not exclude that media in the path of propagation including the earth as a receiver of light might have a more or less dragging and possibly also delaying influence. As I read, such questions were and still are subject of research.
However, I cannot find in Einstein's 1905 SR paper to what point he referred the speed of light. Has a lot of physics been based on a missing reference?
Eckard
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John Merryman replied on May. 17, 2011 @ 02:01 GMT
Tom,
I'm not the one setting the field up for a fall.
Lawrence,
What are your thoughts on this paper:
http://www.fqxi.org/data/forum-attachments/2008CChrist
ov_WaveMotion_45_154_EvolutionWavePackets.pdf/link]
Eckard,
Su
bjectively the individual brain is a single point of reference in a physically dynamic context. The right side amounts to a complex thermostat, evaluating the various elements of this context. The left side is a complex clock, sequencing the changing configurations of this context. As we are propelled about in space, we transition through series of events, but the larger physical reality is that these events are a consequence of the changing configuration of form, not points on a foundational temporal dimension. The constant is the present, not the events, or their four dimensional geometric configuration. Light only exists in the present. Memory and mass are composed of light, but light has no memory or mass.
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T H Ray replied on May. 17, 2011 @ 15:07 GMT
T H Ray replied on May. 17, 2011 @ 15:10 GMT
"I'm not the one setting the field up for a fall."
And neither is anyone else.
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John Merryman replied on May. 17, 2011 @ 16:59 GMT
Tom,
That's the problem. Everyone has to work within the context of what already exists, if they want to be involved. With everyone focused on ironing out the details, problems become an area of opportunity to solve with more detail work, rather than a reason to review the picture that has emerged.
Consider the link I posted to Lawrence above. It gives a quite reasonable, practical explanation for redshift. No singularity, big bang, inflation, dark energy, multiverses, etc. necessary.
Here is this article by one of the designers of the Hubble telescope and his opinions on cosmology:
http://www.americanscientist.org/issues/pub/2007/9
/modern-cosmology-science-or-folktale"In the 1930s, Richard Tolman proposed such a test, really good data for which are only now becoming available. Tolman calculated that the surface brightness (the apparent brightness per unit area) of receding galaxies should fall off in a particularly dramatic way with redshift—indeed, so dramatically that those of us building the first cameras for the Hubble Space Telescope in the 1980s were told by cosmologists not to worry about distant galaxies, because we simply wouldn't see them. Imagine our surprise therefore when every deep Hubble image turned out to have hundreds of apparently distant galaxies scattered all over it (as seen in the first image in this piece). Contemporary cosmologists mutter about "galaxy evolution," but the omens do not necessarily look good for the Tolman test of Expansion at high redshift."
Yet none of this gets any serious attention from mainstream physics. It's much easier to construct another mathematical formula to explain virtually any problem, that it is peel away the layers and see if there are significant conceptual problems buried in there.
Just because no one is able to bring all the problems together and get them considered, doesn't mean they will go away. It just means another generation of physicists will spend their careers building up a structure that is crumbling at the foundations.
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Eckard Blumschein replied on May. 18, 2011 @ 16:14 GMT
Tom and LC,
I consider the Siegel pamphlet here as inappropriate as LC's attempt to convince John Merryman by means of mathematics that an alternative explanation of redshift is wrong. Do not hide missing arguments behind alleged competence. Cheeky tongues are weak arguments.
Tom, You wrote: "Any good guess supported by real results is good science." Well, whether a guess is really good will be indicated by real results that are unambiguously attributable to it. Is this the case for SR? So far I am not aware of any example for an illogical guess that has proven useful for good.
Let me reiterate my simple question: What does the speed of light in vacuum refer to? The space, the emitter, the receiver, an observer, or what else?
While I usually do not like the thought experiments Einstein is notorious for, I would nonetheless suggest rather simple ones as to test how light behaves. An electromagnetic impulse could be sent through a cable with parts that can be switched on or off during propagation. Intuitively I would not expect a "motion" of the receiver to change the measured speed of propagation.
I would like to second Pentcho who argues: The principle of relativity or the principle of constancy of the speed of light seems to be wrong. My hopefully good guess is: Relativity of time is based on desynchronization. Perhaps already Lorentz transformation is ill-founded. Doesn't theory of relativity even contradict to Galileo Galilei's relativity? Aren't there enough results that confirm my guess? Nobody ever measured Lorentz contraction etc., and there is ongoing trouble with the metric of spacetime.
Eckard
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T H Ray replied on May. 18, 2011 @ 16:42 GMT
T H Ray replied on May. 18, 2011 @ 16:57 GMT
John,
I realize that in the nonscience world, the sins of inefficiency, waste and redundancy are punished and ridiculed. To nature and to science, however, these are assets to creativity.
Science(and liberal, rational thought in general) is founded on intellectual freedom, and free inquiry recognizes above all the right to be wrong.
Worry about science being in jeopardy when freedom itself is threatened. Look for science to flourish when academic freedom spreads beyond the academy. In fact, it is happening in our lifetimes.
Tom
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John Merryman replied on May. 18, 2011 @ 17:46 GMT
Tom,
It's not waste, it's fertilizer.
The same cycles of expansion and consolidation apply to all areas of life. Time decides what is the wheat and what is the chaff.
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T H Ray replied on May. 18, 2011 @ 18:16 GMT
Exactly. Fertilizer.
Without which, there is no wheat.
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John Merryman replied on May. 19, 2011 @ 02:08 GMT
So is it all a self sustaining cycle, or is just that long slide down from low entropy and high energy?
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T H Ray replied on May. 19, 2011 @ 10:07 GMT
A fertilization process is always self-sustaining. Continuous.
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John Merryman replied on May. 19, 2011 @ 16:24 GMT
Eckard Blumschein replied on May. 19, 2011 @ 23:57 GMT
Tom Ray,
Being left-handed, I nonetheless consider myself more even-handed as compared with what you offered "an even-handed treatment of special relativity experimental results".
While I did not at all intended any criticism of SR until recently, I am increasingly sure that the FQXi is a necessary complement to experimental physics because the latter alone seems to be unable to...
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Tom Ray,
Being left-handed, I nonetheless consider myself more even-handed as compared with what you offered "an even-handed treatment of special relativity experimental results".
While I did not at all intended any criticism of SR until recently, I am increasingly sure that the FQXi is a necessary complement to experimental physics because the latter alone seems to be unable to solve most foundational questions.
Unfortunately, the rest of my lifetime will not suffice as to clarify the matter.
At least, the textbook by Bohm I have at hands is among the three recommended by Roberts. What would such a cheeky guy like Einstein say in front of so many "evidence"? Didn't he ridicule the pamphlet "100 arguments (or professors?, I am sorry for my shaky memory) against Einstein" by arguing that they altogether are void and cannot replace a single compelling conter-argument?
With such cheekiness I may also easily invert the biased meaning of what I quote here from Roberts:
"Experimenter's bias is a phenomenon caused by the inability of human participants in an experiment to remain completely objective, in which the human experimenter directly influences the experiment's outcome based upon his or her personal desires or expectations." and "Unpopular or unexpected results may not be published."
I would like to add something essential to the first sentence: I learned not just form Nimtz's consistently measured superluminal signals that the community is obviously not in position or not willing to realize theoretical flaws in the used methods, and this problem gets increasingly worse with procedures and tools that can less and less be checked for plausibility.
While Roberts did not mention Van Flandern he could not deny that Van Flandern was correct: "At this time there are no direct tests of length contraction."
A lot of references are difficult to attribute to the core question. Others were bewildering, e.g., I quote: "Marinov, Progr. in Physics, 1 (2007), pg 31; (posthum. reprint from “Deutscher Physik” 1992). This is a series of experiments using mechanically rotating mirrors and apertures that claim to measure a local anisotropy in the one-way speed of light. Marinov thinks his rotating mirrors and apertures provide an “absolute synchronization” which can be used to measure the one-way speed of light; this is not so, and is a major conceptual error in his design: they merely provide synchronization in the rest frame of his lab." Was Marinov an idiot?
A second example, I quote:"Liquid Scintillator Neutrino Detector (LSND) results have been a puzzle for several years, as they appear to be inconsistent with other experiments. Just recently they were directly contradicted by the Mini-BooNE results from Fermilab (May 2007, no reference yet)."
Interesting to me was the following comment by Roberts: "Lorentz Invariance is the technical term for the statement that SR is valid. Any violation of CPT invariance implies a violation of Lorentz invariance; theories without Lorentz invariance need not have CPT invariance."
In all, I did not yet find any convincing evidence that could refute the numerous serious arguments against the alleged logical consistency of SR. This does not imply that possibly GR is correct at least to some extent. It is not my business to investigate whether or not a re-installation of absolute simultaneity will already provide a way out of notorious trouble. Nonetheless I will appreciate any genuine support for my strict distinction between the usual abstract and infinite to both sides notion of time and what I consider its traceable unilateral basis.
Eckard Blumschein
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Pentcho Valev wrote on May. 16, 2011 @ 05:44 GMT
http://www.scientificamerican.com/article.cfm?id=is-time-an-
illusion
Craig Callender in SCIENTIFIC AMERICAN: "Einstein mounted the next assault by doing away with the idea of absolute simultaneity. According to his special theory of relativity, what events are happening at the same time depends on how fast you are going. The true arena of events is not time or space, but their union: spacetime. Two observers moving at different velocities disagree on when and where an event occurs, but they agree on its spacetime location. Space and time are secondary concepts that, as mathematician Hermann Minkowski, who had been one of Einstein's university professors, famously declared, "are doomed to fade away into mere shadows." And things only get worse in 1915 with Einstein's general theory of relativity..."
Which of the postulates of special relativity - the principle of relativity or the principle of constancy of the speed of light - is false?
Pentcho Valev pvalev@yahoo.com
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Wilhelmus de Wilde de Wilde wrote on May. 16, 2011 @ 15:59 GMT
Absolute simutaneity cannot exist in our 4-d relativistc universe, the principle of relativity in our causal deterministic universe is in my opinion still standing, in
my essay "Realities out of Total Simultaneity" I am proposing that in a NON causal dimension (after Planck length and time) there is an absolute simultaneity of all possible moments and places from where our diverse "world lines" are esthablished by our consciousness.
Regarding the velocity of light : the "local" speed of light will always be c, but the speed of light can and will exeed c when it is in another locality, for example after the Hubble horizon the velocity of galaxies that speed away from us will be greater (much) as c.There are galaxies that are having a redshift of 1,5, this means that they move away from us at the speed of light, the cosmic background radiation has a redshift of about 1100 !, which means that "we" move away from the point of the early hot plasma at the speed of 50 times c.
Furthermore SR is appliccable for objects that move in space, not for space itself ,
Wilhelmus
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Michael Jeub wrote on May. 17, 2011 @ 04:03 GMT
If the hertz is cycles per time, time per cycle some wavelength. Mr. Callender will explore what that experimental wavelength is to various interpreters. If this length is off by 120 orders of magnitude or whatever in the total expansion of space as we may know it, then certainly some valuations of what that length will fall off the traditional relativistic order of time in Lorentian-Minkowsy iso-spin space and stuff. As pertaining to kinship, I value the beginnings which have mystified me: the now that was. The baggage along time's wayside is undervalued, so I hope that the experiment fails in this extension to kinship. Long term evolution and inheritance are drivers that shape and maximize the footprint of the future.
Here's another related idea. What does it mean for an investment or security to "mature"? It must mean to follow some life cycle without being recharged or reinvested, but there are so many ways of resecuritizing and recapitalizing that one loses the small incoate pieces from which the thing sprang. So everything ends in the future with maturity of some asset, but the engendering of that future vector looks back to its first expressions, and not narrowly to kin. We, by ourselves, be befriended, as someone once told me and I have not forgotten.
In computing, there are signed and unsigned variables. We need both for our clocks to sync and pulse, so it should be with the pointers to past and future. In each case there is a reset marker.
Congratulations on the grant, Mr. Callender.
Michael Jeub
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Eckard Blumschein replied on May. 17, 2011 @ 15:14 GMT
Michael Jeub, You wrote: "In computing, there are signed and unsigned variables. We need both for our clocks to sync and pulse, so it should be with the pointers to past and future. In each case there is a reset marker."
In case of computing on the level of abstraction, you were correct and able to support Callender. However, analog as well as real-time computing are bound to reality, and that's why they do not in principle need negative elapsed time. Even if Strauss-Kahn, Berlusconi, etc. might desire a reset button. It is not available.
Eckard
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Pentcho Valev wrote on May. 17, 2011 @ 08:31 GMT
http://www.fqxi.org/grants/large/awardees/view/__details/201
0/callender
Craig Callender: "Physics sees time as like space."
Physics does not "see" time as like space. Rather, it DEDUCES a space-like time, from two postulates: the principle of relativity and the principle of constancy of the speed of light. If Callender believes that "time in physics is surprisingly different than space", then he should expose the false postulate. That is the only honest approach.
Pentcho Valev pvalev@yahoo.com
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Pentcho Valev replied on May. 18, 2011 @ 05:37 GMT
http://www.amazon.com/Relativity-Simultaneity-Routledge-Cont
emporary-Philosophy/dp/0415701740
Einstein, Relativity and Absolute Simultaneity (Routledge Studies in Contemporary Philosophy): "Unfortunately for Einstein's Special Theory, however, its epistemological and ontological assumptions are now seen to be questionable, unjustified, false, perhaps even illogical."
Craig Callender, you are one of the authors of this book. Which postulate of special relativity is false: the principle of relativity or the principle of constancy of the speed of light?
Pentcho Valev pvalev@yahoo.com
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T H Ray replied on May. 18, 2011 @ 12:13 GMT
Your dichotomy is false.
To treat time like space and vice versa, is to convert units of one into the other. The invariant speed of light in vacuo allows semi-rigid geometrical transformations of mass points; it doesn't possess the power of a postulate, since c is a measured value.
The authors in your source are dealing with a far more subtle issue -- in the philosophy of science, not in the operational meaning of relativity theory.
It has to do with whether a theory need be justified in its assumptions or not. Einstein, like most scientists of his day, was influenced by the school of Logical Positivism in Vienna, where Ernst Mach was a central figure. LP denies any physical reality to phenomena that cannot be directly measured (Mach never accepted atomic theory, e.g.).
Even though Einstein is known for "relativity," Mach was the true relativist. That is, the inertial state of any body is relative to the state of all other bodies in the universe. Because Einstein recognized that all measurements of motion (changes in position among bodies) are taken between mass points and not between points of space, he agreed with Mach in principle -- in fact, he coined the term "Mach's principle" to help explain general relativity -- while disagreeing on the action at a distance that Mach's philosophy implied. Whether Einstein knew of the Michelson-Morley result at the time he wrote his paper is in question, but it really doesn't matter. The invariant speed of light in relativity supports the positivist philosophy while eliminating the "spooky" part of classical physics that Einstein didn't like.
Mach rejected relativity because it gave a role to space (Minkowski space-time) whereas his own philosophy (and all classical physics preceding) assigned no properties to space at all. Einstein acknowledged (in an appendix to _The Meaning of Relativity_) that "From the standpoint of epistemology it is more satisfying to have the mechanical properties of space completely determined by matter …" yet it was apparently even more satisfying to have a way to determine rest states of matter, because it led to mass-energy equivalence, the startling conclusion of special relativity.
Today, most theorists favor some form of metaphysical realism as conceived by Karl Popper, rather than to try and justify assumptions as required by positivism. Any good guess supported by real results is good science. So whether Einstein is justified or not from an epistemological-ontological standpoint, or just made the right guess, is a question for philosophers to ponder, while science moves on.
I expect that if Einstein were alive today, he would feel freer to make conjectures, justified or not.
Tom
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J.C.N. Smith replied on May. 18, 2011 @ 14:42 GMT
Tom,
"Any good guess supported by real results is good science."
Well said.
jcns
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Lawrence B. Crowell wrote on May. 17, 2011 @ 18:10 GMT
I am not sure whether the wave physics in the paper by
ov_WaveMotion_45_154_EvolutionWavePackets.pdf' target='new'>Christov involves quantum mechanics. The dissipative equation has a solution with a complex frequency. An instanton or tunneling state has a frequency or wave number that is imaginary, eg multiplied by i = sqrt{-1}. However, a complex frequency ω = α + iβ means...
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I am not sure whether the wave physics in the paper by
Christov involves quantum mechanics. The dissipative equation has a solution with a complex frequency. An instanton or tunneling state has a frequency or wave number that is imaginary, eg multiplied by i = sqrt{-1}. However, a complex frequency ω = α + iβ means the system has dispersion and dissipative physics. This demolishes some foundations of quantum mechanics in a way which I find terribly problematic. So as a fundamental wave equation for a free particle this is not likely to be fundamental.
The wave equation is argued to be a source for the redshift of galaxies. A variant of this wave equation could be derived with general relativity for the de Sitter spacetime. The metric is
ds^2 = dt^2 – e^{sqrt{Λ/3}t}(dr^2 + r^2dΩ^2)
where we only consider the metric coefficient g_{rr} = -e^{sqrt{Λ/3}t} and g_{tt} = 1 to ignore rotational motion. The Christoffel symbols are
Γ^a_{bc} = (1/2)g^{ad}(g_{db,c} + g_{dc,b} – g_{bc,d})
which, as I calculate in my mind, leaves us with
Γ^t_{rr} = -(1/2)g^{tt}g_{rr,t} = (Λ/3)e^{sqrt{Λ/3}t}
This connection coefficient is used in covariant derivatives
Du^a/ds = du^a/ds + Γ^a_{bc}u^bu^c,
where for u^a = dx^a/ds this is the geodesic equation if the acceleration Du^a/ds is zero.
So for the vector valued wave function u^a the time derivative ∂u^a/∂r = ∂_ru^a requires a covariant derivative
D_ru^a = ∂_ru^a + Γ^a_{rc}u^c
which requires the index c -- > r and
D_ru^a = ∂_ru^a + Γ^t_{rr}u^t
= ∂_ru^a + (Λ/3)e^{sqrt{Λ/3}t}u^t.
The second derivative would then be
D^2_ru^a = = ∂^2_ru^a + 2(Λ/3)e^{sqrt{Λ/3}t}u^t + (Λ/3) e^{sqrt{2Λ/3}t}u^t.
That is rather messy, so I will Taylor expand the exponential and keep only factors O(Λ) and we get
D^2_ru^a = = ∂^2_ru^a + 2(Λ/3)u^t.
So the wave equation is adjusted to
0 = ∂^2_tu^a - D^2_ru^a = ∂^2_tu^a - ∂^2_ru^a - 2(Λ/3)u^t.
In now use the light cone condition that u^t = g_{rr}u^r for a massless particle and I have the wave equation
∂^2_tu^a - ∂^2_ru^a - 2(Λ/3)u^r = 0.
I now let u^r = a exp(ikr – iωt) and substitute this in to get the condition
-ω^2 + k^2 – 2i(Λ/3)k = 0
k = i(Λ/3) +/- sqrt{- i(Λ/3)^2 + ω^2}
The binomial theorem is used for ω^2 >> |(Λ/3)| and we get an approximate answer
k =~ {iΛ/6 - ω, iΛ/2 + ω}
The result is a dissipative dispersion relationship. The photon loses energy, it loses energy to this cosmological gravity field. This loss of energy manifests itself as the redshift. The second solution may be written as
ω = k - iΛ/2
and a wave function Gaussian wave packet
u^r = exp(β(k – k’)^2/2)exp(ikr)
has δk/k = βΛ/2 which for β = 8πGt/3k and H^2 = 8πGΛ/3 this gives the time dependent spread of the wave packet with time.
In this approach, which I worked on screen and took far more time than I was wanting to spend, there is no need to posit a quantum field which has some dissipation term, which leads to non-unitarity in quantum mechanics. Non-unitary quantum mechanics would mean the universe is far less sensible. So based on what I have done here, modulo any math error which might have occurred due to working this in my mind, the expansion of space can quite adequately account for this red shift.
Cheers LC
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John Merryman replied on May. 18, 2011 @ 03:01 GMT
Lawrence,
Thank you for taking the time to work that out. Obviously I'm not able to follow your analysis, but it is obvious it did contain food for thought for you. Necessarily reality will always be more complicated than we can perceive, as our powers of perception are a component of reality.
One question; Is there a mathematical distinction between the expansion of space containing light and the expansion of light in space? It seems to me that the treatment of light in relativity is only a function of distance, not volume. Yet the further light travels, the greater the volume it must encompass and this would quite logically reduce its energy. Yes, I know we measure light in terms of photons and assume they are particles of light that have traveled individually from the source, no matter how far away it is. Yet we also know quantum particles are fundamentally entangled, so it would seem that light being emitted from a source amounts to one large quantum entity and the particular quanta we measure are largely a function of the mass structure of our measuring devices. As Christov points out, those "wave packets" are not single spectrum entities and as you observe, it does make it far more complicated.
Otherwise our current model does require quite a number of interesting additions in order to function. As I keep pointing out to Tom, even Paul Steinhardt is starting to raise questions about inflation.
The stability and strength of the models are not a function of our belief in them, but their irrefutable logic and this requires constant probing for the weaknesses, not trumpeting of the strengths.
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Lawrence B. Crowell replied on May. 18, 2011 @ 20:34 GMT
The major distinction is that a quantum theory of waves that have them dissipating this way would not be unitary. This causes lots of damage to basic concepts in physics. It is actually at the heart of the problem with quantum gravity. If space expands the energy of a photon is then taken up by the gravity of the universe, here the “gravity” being the Einstein dynamics of the expanding spatial manifold.
Cheers LC
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John Merryman wrote on May. 19, 2011 @ 02:42 GMT
So the wave aspects of reality are ignored because it messes up the theories?
Wouldn't the energy also be taken up by expanding volume of space and you end up with redshifted light, until all that's left is that black body radiation we see emanating from the edge of the visible universe.
What if they don't find the Higgs? Then everything can't be explained by particles.
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Lawrence B. Crowell replied on May. 19, 2011 @ 12:33 GMT
The point is that quantum waves need to evolve by unitary quantum mechanics. Unitarity is preserved with cosmological red shift by expanding space. This is not the case with a nonlinear wave equation.
Cheers LC
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T H Ray replied on May. 19, 2011 @ 13:15 GMT
John,
One has to study classical mechanics in order to understand quantum mechanical unitarity. I tried to make the point as simply as possible in my FQXi 2008 essay, that volume preserving is energy conserving.
Seriously, if you would please just get a good grasp on the basics, theorists would not seem as wacky as you imagine. Your intuition cannot fill the gaps in knowledge.
Tom
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John Merryman replied on May. 19, 2011 @ 16:17 GMT
Tom,
I agree I'm an idiot on the subject, but the gaps I keep having problems with are those which keep popping up between theory and observation, that get filled in with increasingly bizarre ideas, supposedly supported by ever more complex math.
While you keep telling me I have no idea what I'm talking about, you seem to have no recognition that it is a fairly classic social phenomena for belief systems not to question core principles when reality does not cooperate, but to blame the problems on everything else, rather than reconsider those core assumptions.
I don't doubt that reality is far more strange than our basic, normal human perception thinks of it as, but it does seem as though physics is also susceptible to making up answers when it really doesn't know, then not being able to let go of those fabrications as they become ever more imbedded in the network of knowledge.
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T H Ray replied on May. 19, 2011 @ 17:30 GMT
John,
Physics is a science, not a "belief system." When ideas don't work (e.g., luminiferous ether, phlogiston, planetary atomic model, etc.) they are thrown out, modified or ignored.
The mathematics that supports leading edge theories seems complicated to you because one has to be grounded in fundamental physics, as I have emphasized, to see that the connection is complete and the extensions are reasonable. Whether these particular techniques and methods are the best ways to deal with the problems is an entirely different question with which researchers wrestle every day.
You do your intellect a great disservice, however, to simply dismiss the solutions as "fabrications" of a society subset that has some mysterious power to determine the course of physics knowledge for the whole population.
One cannot effectively question "core principles" that one hasn't studied. You have the capacity -- it's beyond me why you don't use it.
Tom
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Eckard Blumschein replied on May. 19, 2011 @ 22:31 GMT
LC,
When I heard lessons on probability about 50 years ago, I was told without explanation that ergodicity is a hypothesis. Well, unitarity is also considered essential to a lot of theory. However if used in physics, is it really more than a hypothesis?
There are crowds of those who do not trust in Cantor's and Einstein's admittedly paradoxical ideas. Maybe, their criticism is even largely correct. Nonetheless I wonder why almost nobody thoroughly deals with pre-runners like Bolzano, Weierstrass, Dedekind, Voigt, Lorentz, Poincaré, etc., and I got not aware of someone who put the unitarity of the world in question.
I was educated from engineers who were convinced that the world is not a closed system. If I understood you correctly, then inflation is required as to maintain the perhaps arbitrarily chosen hypothesis of an unitary (closed) world?
Eckard
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John Merryman replied on May. 20, 2011 @ 01:33 GMT
Tom,
Thank you for the compliment. I am a bit of the product of my environment. Lots of emphasis on work and not so much on education. I respect the total commitment it takes to become truly professional at many areas of expertise, but I also recognize that it distorts one's perspective. I grew up around horsepeople and that's the major subject of discussion. Occasionally I can get a conversation going about economics, especially since the recession, but that's about as deep as it gets. My interest in physics is due to the understanding of the laws and processes governing everything. So for me, physics is profoundly intuitional. I know that sounds like heresy, but I really don't have problems with viewing reality as fundamentally illusionary and that even coming to some degree of understanding is itself something of a contradiction, since knowledge is necessarily reductionistic. To the extent I live my life as a flash of light, I'm living it as I understand it. Thus it's more an intuitive juggling act, than a course of singular study.
"Physics is a science, not a "belief system." When ideas don't work (e.g., luminiferous ether, phlogiston, planetary atomic model, etc.) they are thrown out, modified or ignored."
Yet you don't think that various of today's theories might also be scales that will eventually fall from our eyes? The problem is that many of them are interconnected in ways that dropping one will raise problems for others and few in the theoretical community want to start pulling that string. Yet it seems that many with strong professional interests in these ideas(computers, electrical engineering, etc.) do think there are serious conceptual problems, but make do, without making a huge issue of it.
It does bear some resemblance to a priesthood, with a laity that is not quite as committed, but still need and like the community.
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Lawrence B. Crowell replied on May. 20, 2011 @ 04:14 GMT
Unitarity just means that any operator which transforms a quantum state Uψ = ψ’ is such that its transpose in a matrix representation and complex conjugate, denoted by † is such that U^† = U^{-1} and for an operator H which is the generator of U, U = exp(iH) then
U^† = exp(iH^†) = U^{-1} = exp(-iH)
And so H^† = H. The theory of quantum mechanics based on this has been experimentally tested thousands of times. So unitarity is more than a hypothesis.
Ergodic theory is more hypothetical because it is based on a certain interpretation of statistic. This is a form of frequentism.
Cheers LC
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T H Ray replied on May. 20, 2011 @ 10:50 GMT
John,
You wrote, "Yet you don't think that various of today's theories might also be scales that will eventually fall from our eyes?"
It doesn't matter what I (or anyone) thinks. I can't emphasize enough that personal belief plays no role in science. I cited previously the example of phlogiston as a once widely accepted physical principle that we now know is superfluous. Where chemists once thought that an unknown substance (phlogiston) was necessary to make fire, because they couldn't understand combustion otherwise, after Lavoisier demonstrated that combustion is simply a process of rapid oxidation, phlogiston ceased to be an issue. It hardly serves science to look back and say "How stupid could one have been to accept such an idea in the first place?" when patient researchers were producing results step by step regardless of their innocence of the correct solution. And it's only the crankiest of accusers who would say before or after Lavoisier's discovery, "I told you that you were wasting your time on that idea," based on nothing more than some vague intuition, and having invested no intellectual toil and sweat in trying to produce the correct result themselves.
Scientists make conjectures and offer refutations based on the state of knowledge as it is, not on what they personally believe. The overwhelming proliferation of information today has made it all but impossible for an individual to hold all the knowledge, so debates are more intricate and sophisticated than they ever were. Nevertheless, facts and theorems still rule, and a counterexample is worth a thousand words.
Tom
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J.C.N. Smith replied on May. 20, 2011 @ 11:37 GMT
John,
Apropos what Tom is talking about regarding how science has progressed over the course of history, in case you've not already read Thomas S. Kuhn's book 'The Structure of Scientific Revolutions' it's a wonderful read, imo. Puts some of the history of science in an interesting and useful light. Paradigms play an important role in shaping the way we think about the things we observe empirically, and Kuhn's book addresses the issue of paradigm change. Fascinating stuff.
In our discussions here at FQXi I've attempted to focus on the fundamental paradigms we're using when we talk about slippery topics such as "time." I continue to believe that this focus on paradigms is a potentially fruitful avenue to pursue. Paradigms are necessary to permit the creation of scientific theories, but paradigms also can tend to create tunnel vision in the way we think about the things we observe. It's something to be mindful of. Anyway, I can't recommend Kuhn's book too highly. I've read it several times and will undoubtedly revisit it for a refresher.
jcns
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Lawrence B. Crowell replied on May. 20, 2011 @ 18:01 GMT
I have to second TH Ray’s comment. A theoretical physicist might get some idea about things and work hard to develop a hypothesis. Even though that person might really hope their work is found in nature there is no believing. This is not about wanting nature to uphold one’s hopes, for we should not equivocate truth with hope.
Cheers LC
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John Merryman replied on May. 21, 2011 @ 01:50 GMT
jcns,
There was a book written in the 70's called Paradigm Shift, that was one of the first books on physics I read and it was influential to my thinking. I tried looking it up, but having forgot the author and it likely being out of print, it didn't show up. The term gets lots of use these days. I tried writing a blog when they first became common, and titled it Peeling Paradigms. There definitely seems to be something of a cyclical nature to the process, as old paradigms age and congeal, which creates the need and space for fresh paradigms to rise.
Unfortunately I'm working two jobs lately and the time to read much of anything has become quite limited.
Tom and Lawrence,
"I cited previously the example of phlogiston as a once widely accepted physical principle that we now know is superfluous."
So spacetime as a "physically real model" is irrefutable. And blocktime and wormholes and all the other fantastical ideas springing from it.
"This is not about wanting nature to uphold one’s hopes, for we should not equivocate truth with hope."
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Eckard Blumschein replied on May. 21, 2011 @ 08:56 GMT
LC,
You argued: "The theory of quantum mechanics based on this has been experimentally tested thousands of times. So unitarity is more than a hypothesis."
While QM is a rather confirmed theory, its application to cosmic scales might be a rather wild guess, at least to me. Is it not a bit far fetched to absolutely exclude the possibility that CMB radiation can be explained without cosmic inflation on this basis?
Eckard
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John Merryman replied on May. 21, 2011 @ 10:44 GMT
Eckard,
The irony is that the math is likely far more comprehensible for a non-inflationary cosmology. Einstein originally proposed a Cosmological Constant to maintain a stable universe and expansion has shown to resemble a CC. So it would seem "space" expands between galaxies proportional to the rate it collapses within them and this is not coincidence, but two sides of the same process. Yet it seems the case has been closed and cannot be reopened, because this generation of theorists were raised to this view.
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Lawrence B. Crowell replied on May. 22, 2011 @ 17:26 GMT
The CMB exists without inflation. It is predicted by the standard FLRW spacetime model of the big bang. What inflation does indicate is how the CMB is smooth with small anisotropy. It also tells us how different regions of the CMB originated from the same initial conditions.
The quantum aspect of inflation is the vacuum energy stretched out space enormously, about 63 efolds. The vacuum energy just defines an energy density
T_{00} = Λg_{00} = (8πG/c^2)ρ,
for ρ the energy density of the vacuum. So the vacuum energy provides the energy for the dynamics of space, where that dynamics is purely classical.
Cheers LC
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John Merryman replied on May. 23, 2011 @ 01:28 GMT
Lawrence,
What would light be that has been completely redshifted far beyond the visible scale? Wouldn't it resemble the black body radiation of CMBR?
Wouldn't it also have small distortions around where the emitting source is located, like ripples in a stream around a submerged rock?
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Lawrence B. Crowell replied on May. 23, 2011 @ 13:46 GMT
The CMB has a thermal or blackbody distribution of frequencies. This peaks in the microwave region. We identify infrared with heat because the blackbody distribution peaks for most hot sources in that region. There is actually nothing fundamental about that. A blackbody curve can peak in the extreme gamma radiation frequency range, and in fact did so during the rather early universe.
Other galaxies outside our local group will red shift increasingly. In 10 billion years they will only be observed in the IR band. However, the distribution of frequencies from these sources will not be Gaussian or blackbody. As this occurs however, the time of arrival rate for photons will decrease, their wavelengths will increase and it will becomes very difficult to detect them.
Cheers LC
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John Merryman replied on May. 23, 2011 @ 17:04 GMT
Lawrence,
Just in theory, assume there are infinite numbers of galaxies in infinite space. So that even radiation from much further than 13.7 billion lightyears away eventually reaches us. Wouldn't that distribution of sources fill in all the gaps and result in a black body radiation below the infrared and in the microwave?
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T H Ray replied on May. 23, 2011 @ 18:27 GMT
" ... assume there are infinite numbers of galaxies in infinite space ..."
Why?
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T H Ray replied on May. 23, 2011 @ 18:32 GMT
John Merryman replied on May. 24, 2011 @ 01:17 GMT
Tom,
If redshift is a function of distance and not recession, then that black body radiation is the light from those infinite numbers of stars. It has just fallen off to the microwave spectrum.
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John Merryman replied on May. 24, 2011 @ 01:26 GMT
Tom,
Lawrence's post, 5/23, at 13:46;
" As this occurs however, the time of arrival rate for photons will decrease, their wavelengths will increase and it will becomes very difficult to detect them."
From my essay in the recent contest;
"As the light from a star expands out to fill the volume around it, it necessarily grows
more diffuse, as the same amount of energy must cover ever more volume. The further
away that star is, the smaller it appears and the fainter its light gets. Since the smallest
measurable quantity of light we can detect is what will trip that electron, eventually it
reaches the point that barely enough is reaching our detectors to even trip one atom on
the detector. Beyond that and the duration between the detections start getting further
apart, so that the resulting wave pattern created by the continuing process of measuring
these photons will have longer wavelengths."
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Pentcho Valev wrote on May. 19, 2011 @ 06:00 GMT
Craig Callender suggesting, very carefully, that Einstein's 1905 constant-speed-of-light postulate might be false:
http://www.thedivineconspiracy.org/Z5237I.pdf Craig Callender: "We think it's impossible that photons go faster than relativity claims. Why? Because our most powerful theories, the theories upon which we base our explanations and predictions - upon which we even stake our lives - say so. (...) We don't have to be too strict about this. Scientists are free to devise models of the world wherein (say) the absolute speed of light is not constant."
If Einstein's 1905 constant-speed-of-light postulate is false, then the Michelson-Morley experiment says that the antithesis of the postulate given by Newton's emission theory of light, the equation (c' = c plus v) showing how the speed of light varies with v, the speed of the emitter relative to the observer, is true:
http://philsci-archive.pitt.edu/1743/2/Norton.pdf John Norton: "The Michelson-Morley experiment is fully compatible with an emission theory of light that CONTRADICTS THE LIGHT POSTULATE."
Pentcho Valev pvalev@yahoo.com
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Pentcho Valev replied on May. 20, 2011 @ 05:36 GMT
In 1954 Einstein confessed, in a somewhat enigmatic way, that his 1905 constant-speed-of-light postulate was both false and fatal for contemporary physics:
http://www.perimeterinstitute.ca/pdf/files/975547d7-
2d00-433a-b7e3-4a09145525ca.pdf
EINSTEIN'S 1954 CONFESSION: "I consider it entirely possible that physics cannot be based upon the field concept, that is on continuous structures. Then nothing will remain of my whole castle in the air, including the theory of gravitation, but also nothing of the rest of contemporary physics."
The analysis showing that "physics cannot be based upon the field concept, that is on continuous structures" is equivalent to "physics cannot be based upon the 1905 constant-speed-of-light postulate" is not difficult to perform.
Pentcho Valev pvalev@yahoo.com
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Eckard Blumschein replied on May. 20, 2011 @ 23:04 GMT
While I cannot see from Stachel's presentation that Einstein gave up constant speed of light, the late Einstein did indeed explicitly utter that the NOW worried him seriously.
As indicated by Stachel, several physicists already looked for ways out of some problems by elaborating the idea of discrete spacetime. Such approach seemed to be promising because it could be declared a legacy of the idol.
I wonder if someone was courageous enough as to create a non-tense-less physics which will presumably indeed render a lot of "contemporary physics" a "castle in the air".
Eckard
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Robert L. Oldershaw wrote on May. 19, 2011 @ 15:45 GMT
A huge population of unbound planetary-mass objects was predicted in the Astrophysical Journal in 1987 [vol. 322(1), pgs. 34-36]. Pulsar-planets were also later predicted in a published paper.
A discussion of this form of dark matter ,and its detection via microlensing was published in:
http://arxiv.org/ftp/astro-ph/papers/0002/0002363.pdf
[Fractals 10(1), 27-38, 2002]
It is a great pleasure to see this population finally being revealed to us. The stellar-mass MACHOs and the planetary-mass unbound objects discovered via microlensing may constitute the galactic dark matter, and its specific two-peak mass spectrum was predicted definitively almost 25 years ago. It has been a long wait, but better late than never.
Robert L. Oldershaw
http://www3.amherst.edu/~rloldershaw
Discrete Scale Relativity; Fractal Cosmology
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Marcel-Marie LeBel wrote on May. 21, 2011 @ 02:23 GMT
TH,
I was recently trying to work out what maths means for the universe by opposition to what it means to us. For example, if I have $5 in the bank and $5 in my pocket and “have” a total of $10. This is about adding some knowledge. But if we look at planets, they increase or add mass by getting matter closer to their surface. So, I figure that the natural equivalent to addition is grouping or getting things closer together. Subtraction would be the reverse, again distancing two things apart. But what happens is we increase the distance between all the parts of a group? We dilute its concentration and that would be a “natural” division. A multiplication would amount to a general volume reduction or concentration.
How could one make some sense of this kind of maths? First, it would seem that natural maths is intrinsically tied to geometry. In our minds we may make calculations, but in the real world of real stuff ... addition of things that exists requires a place for those things to exist before we get to add them.
Secondly, my earlier exploration was meant to explain why nanometre size light photons have “more energy” than kilometre long radio photon... In that context, it was explained that both photons have the same “energy”, the Planck. Their real difference was their power. The nanometre photon just delivers more quickly its Planck than the radio photon. In other words, in a universe where time passing is the basic canvas, how quickly something happen does matters. So, a grouping could be associated with an increase of power of the whole group... ?? Power of what? Power of existence? Maybe (for whatever it means). Because the background is passing time, existence (matter existing) is not state! It is an actual dynamic process that can therefore be associated with a time rate and a kind of power of existence, of sort. ...
Strangely, while the universe is expanding (in division), everything existing in it is in a grouping mode (multiplication a.k.a. universal gravitation.)
Just having fun!
Marcel,
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Pentcho Valev wrote on May. 23, 2011 @ 05:36 GMT
Anil Ananthaswamy wrote: "Unfortunately, physics treats time rather differently. Einstein's theory of special relativity presents us with a four-dimensional spacetime, in which the past, present and future are already mapped out."
Equivalently, Anil Ananthaswamy could have written, referring to Banesh Hoffmann's text below: "Unfortunately, Einstein resisted the temptation to account for the null result of the Michelson-Morley experiment in terms of particles of light and simple, familiar Newtonian ideas":
http://www.amazon.com/Relativity-Its-Roots-Banesh-Hof
fmann/dp/0486406768 "Relativity and Its Roots" By Banesh Hoffmann "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd... (...) And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."
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Eckard Blumschein replied on May. 26, 2011 @ 17:52 GMT
Our tense-less time scale from eternity to eternity is a mistake that can be attributed to the bible and maybe Descartes rather than to Einstein. Already Oliver Heaviside introduced the fictitious split of the not yet existing future into an even and an odd component. Not just Tom and LC are still convinced to solve the most foundational imperfections by means of mathematics. I do not share this attitude.
Among the first who admired Einstein's SR was a coworker of Max Planck: Max von Laue. He was born in 1879 as also was Einstein. He discovered compelling evidence for radiation to be an electromagnetic wave, he supported SR, and he got the Nobel price in 1914. Why did he not realize or at least not admit that Poincarè's synchronization is logically flawed?
Eckard
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Pentcho Valev replied on May. 27, 2011 @ 11:53 GMT
Eckard Blumschein wrote: "Our tense-less time scale from eternity to eternity is a mistake that can be attributed to the bible and maybe Descartes rather than to Einstein."
Let us only concentrate on the properties of time that deductively follow from Einstein's 1905 constant-speed-of-light postulate. Craig Callender, Lee Smolin, John Norton seem to reject those properties without questioning the postulate, an approach that is not very fair. If you don't accept the consequences, you should declare the premise false, no matter what catastrophe in mainstream science might occur.
Pentcho Valev pvalev@yahoo.com
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Eckard Blumschein replied on May. 27, 2011 @ 22:33 GMT
A Nobel price winner of Polish origin, I forgot his correct name, maybe Wilczek or so, called my essay to long and boring. Perhaps, my reasoning is too simple as to be taken seriously. My starting premise is causality of reality. In reality, future processes did simply not yet have any effect. I see this a strong argument against Einstein's first postulate.
His constant-speed-of-light postulate is the second one, and I do not see any reason for sharing the widespread doubt on the correctness of his second one. If light has the same properties as have other waves than this includes a maximal speed. I do not overvalue the attempts to enforce an interpretation of failed experiments for pinpointing a hypothetic ether relative to which the earth was thought to move. The speed of electromagnetic waves can be measured, and propagation of signals faster than light proved impossible.
On the other hand, apparently nobody objects against the seemingly reasonable first postulate. I may be the first one who disagrees: Even if we do not question that the differential equations of physics will remain valid in future processes too, the reality corresponds to cumulative influences from the past, and the belonging integral relationships cannot be shifted. Future processes do not yet exist.
Accordingly, Poincaré's method of synchronization is not fair. With reference to the moment of reflection, the moments of emitting the signal and of receiving the reflected one are located in the past and the future, respectively. Hence, such procedure is not always correct in reality.
Paradoxes may be valuable indications of mistakes. It would not be honest if I signed the petition concerning the interpretation of the twin paradox. I see it one of several indications for the inconsistency of Lorentz transformation.
Incidentally, while Tom referred to "Olber's paradox" I consider Olbers' mistake simply an indication of naive thinking.
Eckard
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Lawrence B. Crowell wrote on May. 23, 2011 @ 23:33 GMT
I am answering this in a new text box.
An infinite universe is plausible. The RxR^3 topology of the universe may not have the same vacuum structure everywhere. There may be these zones where the vacuum energy Λ_0 >> Λ, where Λ_0 and Λ are the bare vacuum and the broken vacuum cosmological constant. So our observable universe may have a sort of barrier, where...
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I am answering this in a new text box.
An infinite universe is plausible. The RxR^3 topology of the universe may not have the same vacuum structure everywhere. There may be these zones where the vacuum energy Λ_0 >> Λ, where Λ_0 and Λ are the bare vacuum and the broken vacuum cosmological constant. So our observable universe may have a sort of barrier, where signature of that might exist on the CMB. This is the Linde pocket universe model, and these bubbles are due to the physics of Coleman --- called bubble nucleation. There some good reasons to think this is the case.
However, we can assume the vacuum is the same for the entire R^3. Any observer looking out will see galaxies and objects further out move at increasing velocity, indeed faster than light. If the space is infinite the velocity as one looks out to infinity becomes infinite. I outline how this works below. So if that happens then any photon emitted sufficiently far out is not just red shifted to the IR or into the radio wave band. It red shifts beyond the horizon length ~ 10^{10} light years. Again I illustrate what the horizon is below. So this quells the Olber’s paradox, for anything sufficiently far out is redshifted to such low frequencies that it is not very observable. Further. anything that far out emits photons along our light cone from behind the CMB opaque region. This means such photons are swamped by that boundary This would not be the case if these quanta are in the form of neutrinos. In principle with neutrinos we could observe the universe at a time far earlier than the CMB. Gravitons similarly could permit us to observe right to the quantum gravity event. These gravitons would be red shifted into long wave length gravity waves which might perturb the CMB in so called B-modes.
The problem with an infinite universe with a single vacuum is that it means our past light cone extends infinitely outwards. In order to have a finite time it means the initial inflationary period involved an infinite expansion. That is a bit of trouble. So to prevent some problems the Linde pocket universe idea (eternal inflation etc) is a better candidate. However, the whole R^3 contains an infinite number of these pockets expanding out at an extremely rapid rate. So in some sense we have pushed the problem out to another level. So this R^3 might have started out as a three sphere S^3 where a point was removed and that topological information is involved with quantum information of these bubbles that are finite in number. Further, for reasons I will go into right now, that huge vacuum these bubbles are contained in may run down, which would also mean the creation of pocket cosmologies is finite and of brief duration.
The expansion of the universe is described by a scale factor a(t). Given a radial distance r the scale factor a(t) gives a new radial distance r’(t) = a(t)r. I will use Newtonian mechanics and gravity, for it turns out that this gives the same thing as general relativity for flat space, but curved spacetime. General relativity is somewhat complicated to work with. We have for Newtonian mechanics with gravity that the kinetic energy of a moving object is (1/2)mv^2 and that the potential energy is -GMm/r. The total energy is the sum of these. The velocity is determined for our situation by the scale factor so that r(t) = a(t)r and v(t) = (da/dt)r. A little bit of calculus is entering in here. So the total energy we can set to zero, and we have
(a’)^2 = 2GM/a, a’ = da/dt
We then have M = (4π/3)d (ar)^3, for d = density of matter in a spherical region of radius r’ = a(t)r. We then write this dynamical equation as
a’^2 = 8π Gd a^2/3,
where the Hubble factor is H = a’/a. Now if I assume that the density is constant then this is a differential equation a’ = Ka, for H = sqrt{8πGd/3}, and the solution is
a(t) = (1/H}exp(Ht).
So the scale factor expands exponentially. This is approximately a de Sitter spacetime configuration.
The Hubble factor for small time gives v = Hr, for r a small radius out related to a time t. For v = c one can compute the radius where that occurs and we have r = c/H which is the cosmological horizon distance
R = 1/sqrt{8πG/3c^2} = sqrt{3//\}
Where /\ is the cosmological constant. This horizon distance is about 10 billion light years.
This event horizon is not a barrier to our ability to observe things. It is similar to the event horizon of a black hole, but it is analogous to looking out into the exterior world from inside a black hole. It is a barrier to our ability to send a signal to anything beyond this distance. A galaxy with a z > 1 is beyond this event horizon, and the CMB has z ~ 1000. What happens with galaxies disappearing is that they will accelerate away and become highly red shifted. In about 10 billion years all galaxies outside our local group will be red shifted out of the optical band. An intelligent life form could observe other galaxies if they use IR or microwave instruments. The CMB will recede into the radio wave band and to long wavelength frequencies.
LC
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John Merryman replied on May. 24, 2011 @ 01:42 GMT
Lawrence,
Presumably photons can be entangled. Doesn't it seem reasonable to assume that all photons radiating away from a source are entangled and that it is only when encountering a mass substance, such as that which would manifest a photon detector, that we would observe the "individual" photons?
This goes back to that paper by Christov, where he points out that what generally occurs in nature are multi-spectrum photons/light packets.
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T H Ray replied on May. 24, 2011 @ 11:17 GMT
I find it much easier to accept many worlds, than an infinite R^3 universe.
Infinite red shift freezes observation on the horizon, so even though the horizon is not a barrier, it is a boundary. If we want a continuous model with boundary conditions (I do), to me it seems more plausible to fix the radial length 1 of R^3 on the S^2 manifold embedded in the S^3 topology. /\ can retain its value of very near zero, and quantum mechanical unitarity holds on all time scales calculated in R^2 (in other words, quantum configurations in the Hilbert space can be shown to have correspondence to physical space without regard to locality). This boundary condition allows an R^n universe with no assumption of infinite distance from the origin -- a complete inversion of the general relativity model from finite in time and unbounded in space, to one finite in space and unbounded in time. It makes Einstein's quasi-Euclidean model fully Euclidean.
The only reason I think that /\ is not exactly zero, is the necessary condition for dissipation of thermodynamic information over n-dimension manifolds. Necessary, because continuation of the time metric over S^n implies exchange of energy and therefore entropy production. /\, then, is the universal gravitational constant in a sphere kissing model.
This model also answers the sticky problem you raised:
"So to prevent some problems the Linde pocket universe idea (eternal inflation etc) is a better candidate. However, the whole R^3 contains an infinite number of these pockets expanding out at an extremely rapid rate. So in some sense we have pushed the problem out to another level. So this R^3 might have started out as a three sphere S^3 where a point was removed and that topological information is involved with quantum information of these bubbles that are finite in number."
Indeed, the S^3 topology in an S^n model, by the generalized Poincare conjecture and Perelman's proof, eliminates singularities. The "other level" is then continuation of the time metric over S^n, asymptotic to length 1.
Tom
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John Merryman replied on May. 24, 2011 @ 18:24 GMT
Tom,
That seems more like a statement of preference, rather than an argument against infinite space. With many worlds, you just kick the can down the road, with infinite numbers of bounded spaces. Presumably they are connected.
Just as practice, wouldn't it be possible to consider what a universe of infinite space, subjectively bounded by horizons, might look like?
Yes, it might make a lot of current theory superfluous, but if it works, it would provide a more solid foundation for further mathematical modeling.
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Lawrence B. Crowell replied on May. 24, 2011 @ 20:24 GMT
As I indicated the cosmological horizon is not a barrier to observing the universe beyond it. It prevents one from ever sending a signal to anything beyond it. Anything beyond it will recede away faster than any light signal you might try to send to it. One might think of the cosmological horizon as similar to a black hole horizon for an observer inside the black hole. As you observe further out the velocity of objects will increase to infinity. This means your past light cone will “splay out” in the distant past and cover an infinite R^3. Equivalently inflation was divergent. Of course we have quantum gravity issues, where maybe it does not actually “cover to infinity,” but within a Planck time from the initial R^3 it might then stop. This would be something similar to a stretched horizon in the distant past, within sqrt{Għ/c^5} ~ 10^{-43} sec of the initial spatial slice. So we might think of this as looking at the cosmological horizon from the other side. Maybe, the idea I have been kicking around for a while, where maybe this is equivalent to the rapid flattening of a sphere S^3 after the removal of a point. The hole almost instantly expands to infinity. This would be that huge inflation. For a number of reasons I am not sure how happy I am with this idea though.
The cosmological constant does have to be nonzero for there to be an accelerated expansion of the universe. The horizon distance d = sqrt{3/Λ}. If Λ = 0 then the horizon is at “infinity,” or maybe better put not defined. During the inflationary period of the universe Λ was 100 orders of magnitude larger than it is now.
Cheers LC
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T H Ray replied on May. 24, 2011 @ 22:19 GMT
Lawrence,
I agree with you about the rapid flattening (Euclideanization), except that I find it cannot occur on S^3. I find ("time barrier" fig. S2.2, p. 34) that two Chi = 2 + 2 S^2 manifolds (which is topologically equivalent to S^3), split from the removal of a vertex point on S^9 (10 dimensions), where that configuration is unstable (by the Banach-Tarski construction).
This more supports my conclusion that the four dimension horizon of S^3 is identical to the 10 dimension limit (S^9). The real significance, though, is the unitarity (assuming scale invariance) of the time metric on the classical scale.
Tom
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Lawrence B. Crowell replied on May. 25, 2011 @ 15:42 GMT
The idea is that some “blob” of vacuum energy from “elsewhere,” say some other spacetime cosmology or maybe equivalently from a Dp-brane interaction, quantum tunnels into a new inflationary manifold. At the critical point the S^3 is topologically changed into R^3, and the point which is removed carries the unit of Euler index number or Betti number which manifests itself as topological fields on the manifold. The reason why it would start out as S^3 is a quantum fluctuation of some vacuum energy must be finite, so some volume with a vacuum energy density is involved with the quantum tunneling.
The S^3 is a quantum wave functional, such as a solution given by the Wheeler DeWitt equation. The topological change stretches the S^3 – pt into R^3 and this process is an inflationary spacetime with Λ ~ 10^{120}GeV^4, which is at the Hagedorn temperature, and this topological dynamical change at R^3 has a vacuum state with Λ ~ 10^{100}GeV^4 and the generation of matter fields from the topological quantum number induced from S^3 -- > R^3. This is the space our pocket universe is contained in, where this is a region of symmetry breaking. Then after about 63 efolds from there the cosmological constant exhibits a rapid drop in a bubble of nucleation so Λ ~ 1GeV^4, where this is our “pocket universe.” The vacuum at this lower energy is one of broken symmetry, and this is a phase transition which results in a form of latent heat. This latent heat marks the reheating period and is responsible for the thermal “bang” in the big bang.
There are some technical problems with this though, but it has always struck me as having some attractive features. Maybe if I get the time I will return to this to see if I can make a go of it.
Cheers LC
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Marcel-Marie LeBel wrote on May. 25, 2011 @ 03:57 GMT
I have to accept somehow the many word hypothesis. Ours is a Planck value universe. There are most likely other universes with h+n h-n Planck values
n being any number .. with which we do not interact, like our neutrinos living on the fringe of our Planck universe....
Is there a quantized n values/step between universes? and what is this number?
Marcel,
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Gene T. Yerger wrote on Jun. 1, 2011 @ 14:02 GMT
Anil,
In my book – The Meaning of Time – A Theory of Nothing I introduce a new source for the arrow of time. I call it the intellectual arrow of time. The intellectual arrow of time is closely related to the idea of consciousness. The word consciousness is derived from the Latin conscientia, which may be literally interpreted as shared knowledge. The intellectual arrow represents our insatiable, relentless desire to understand the universe and our place within it. In other words, it represents an intellectual curiosity that, in spite of setbacks that have sometimes suppressed the shared knowledge of humanity, seems at all times to increase towards the future. There are three critical issues involved in defining this arrow of time.
The first issue is that the intellectual arrow of time may be associated with the liberal thinking that manifested itself in Franklin Roosevelt’s New Deal and Lyndon Johnson’s Great Society. It is this author’s view that although purely governmental solutions to societal ills have their limitations, this philosophy represents a relentless trend in history toward the achievement of a more just, more tolerant, and more inclusive society. The future must lie in the direction of advancing ideas that expand the concepts of fairness and justice ─ not in the direction of their suppression.
The second issue is that there are forces in society that would like to stop or slow the intellectual arrow of time – sometimes with good reason. Change can be a destabilizing force in society, and not all change is beneficial or should receive widespread support. At darker times in history, however, the desire to suppress the expression of just ideals has been reactionary. During the Dark Ages, for instance, all the rich culture that had been developed by the Greeks, the Romans, and other nations was repressed by the ruling elite in an effort to control society. There have also been times when the forces of change have been fundamentally immoral. In recent history, for example, the actions of one demented madman led to the senseless death of millions; his agenda was essentially an effort to rewrite history in a way that justified these evil deeds.
And finally, as it ages every generation in some fashion laments the forces of change. This is particularly true in today’s society. On the one hand, the ever-quickening pace of technological innovation has led to a more productive and prosperous society. On the other hand, this largesse has not come without a cost. Rapid change seems to leave in its wake the innocence of our youth. But there is no turning back; there is no way to return to an earlier time when events did not happen so quickly and everything seemed to be less complicated. We can influence the future but we cannot change the past.
Gene T. Yerger
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Eckard Blumschein replied on Jun. 1, 2011 @ 22:20 GMT
"We can influence the future but we cannot change the past." Isn't the direction of causality always valid in nature in general? Just the so called laws of nature are invariant against shift and reversal of time.
I have to admit having confused Nobel laureates. Actually it was a Wilczek who avoided any comment while a 't Hooft pretended having not read my boring essays.
Eckard
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Alberto Gómez Corona wrote on Jul. 22, 2011 @ 14:00 GMT
Craig,
I just read your article in Scientific American 2010. It is very interesting. I fully agree. I´m a physicist. IMHO, I believe that life computes, and does it in the easiest direction. And I think that it is possible to demonstrate that this direction is from lowor to higer entropy. I wrote time ago a short presentation that, thank to your article now I´m extending. Most of the reasoning is paralell to your article here, and IMHO add some additional points realted with how life works. If this add a little clarification I would be very happy.
"Arrow of time determined by life´s easier direction for computation in space-time"
https://docs.google.com/present/view?id=dd5rm7qq_
142d8djhvc8
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Alberto Gómez Corona replied on Jul. 22, 2011 @ 14:03 GMT
"Arrow of time determined by life´s easier direction for computation in space-time"
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JOE BLOGS wrote on Jul. 29, 2011 @ 09:46 GMT
Lets chat.
https://www.sendthisfile.com/Dsi1UcAS1T4nqej4a0zxk1TB
My
clock converts a circular earth orbit into an eliptical one.
And the result is six minutes difference from sidereal time per year.
Approx we take this figure to 10,000 digits of pi accuracy as the formula uses Pi.
A cicular orbit can be in as many as 11 dimensions but these are unstable when an orbit is converted to an elipse it becomes stable in three dimensions plus one of time.
Thus you can reverse the equation to convert Einsteins 4D space time to 11 dimensions.
So you can convert String theory to Einsteins thoery and EInsteins theory back into string theory.
Some scientists believe Einsteins thoery cannot be expressed in 10 dimensions.
Others believe EInsteins thoery can be expressed in as many dimensions as you want to use...................
What do you believe can my thoery work to unify Einsteins thoery and string theory.
And is my clock time more accurate or just an error of six minutes per year rather than a more accurate measurement of time..........................................
Please help me with this problem.
Steve..................
Iam not answering the question myself what I have provided is background to the problem.
The central question is whether Einsteins 4D space/time can be converted to ten dimensions or not.
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Anonymous replied on Jul. 30, 2011 @ 10:47 GMT
The central question is whether there is 4D. And there is not. I will give you a clue, here is a quote from Lorentz 1892 (para 5), this is how it started:
"I have sought a long time to explain this experiment without success, and eventually I found only one way to reconcile the result with Fresnel’s theory. It consists of the assumption, that the line joining two points of a solid body doesn't conserve its length, when it is once in motion parallel to the direction of motion of Earth, and afterwards it is brought normal to it. [The factor being] p2/2V2 . Such a change in length of the arms in Michelson’s first experiment, and in the size of the stone plate in the second, is really not inconceivable as it seems to me".
Paul
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Author/expert Frank Martin DiMeglio wrote on Aug. 9, 2011 @ 19:50 GMT
The key is distance in/of space as it relates to the consequences of touch/motion in (and with) time. The extremes of size, motion, and energy/force have to be equivalent/balanced in conjunction with space manifesting as gravitational/electromagnetic/inertial energy -- as inertia, gravity, and electromagnetism are all key to distance in/of space. (This is the prescription for quantum gravity too.) Fundamentally balanced/equivalent inertia and gravity (both at half strength/force) balances attraction and repulsion.
I have demonstrated all of this in/as dream experience; and, moreover, I have shown the dream to be a linked center of body experience as well. All of us originate at/from the center of the HUMAN body.
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John R. Cox wrote on Jun. 7, 2013 @ 17:43 GMT
While reading in recent years about the conundrum of 'dark energy' it occurred me that since Minkowski it has conventionally been simply assumed that the metric of scale of time to be same as for space. While we cannot look to anything in particular to establish a universal system of scale as absolute, it is quite arguable that as real physical properties the length of a span of duration in the dimension of time is covariant with a commensurate length of a span of directional dimension in space. As illustration, any intersection of time and space would establish the relative scales of length of each for that dynamic locality. In an intersection of a shorter dimension of time with a longer dimension of space, time would be induced to extend producing a corresponding expansion of space in leap-frog fashion until the extensional covariance produces a self-replicating proportion, such as the Golden Mean. If time and space were invariant in scale time would not need extend at all but exist as a static appearance of space. An intersection of a longer span of time with a shorter one of space would induce time to contract with a corresponding dynamic wherein that locality would diminish out of existence. Thus the 'arrow' of time is one of only extension as a physical property.
This is conjecture, of course, as it is difficult to imagine any experimental protocol to support it as hypothesis. Conjecture is therefore a dangerous thing if it satisfies, but not outside the legitimate realm of philosophy which is the discipline of Prof. Callender.
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Shaikh Raisuddin wrote on May. 31, 2017 @ 09:07 GMT
TIME IS MEASURE OF CONSCIOUSNESS
https://www.linkedin.com/groups/3091009/3091009
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