Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Brent, A more general approach than Wheeler's is to understand that all participants in every event, even down to the particle level, are effectively observers of that event. I generalize Wheeler's statement in my book on Reality to explain how every connected network of events essentially functions as a mini-reality accessible only to event participants of their networks, and it is only through networks connecting through common events that those mini-networks become merged into sharable realities in which events become real because they become observable. It's a very important concept that leads to very important conclusions because it shows how GR and QM can be conceptually unified and all Quantum paradox resolved. I explained all this in my New Topic post titled something like Yes, my book does address quantum reality if you want to read more. Best, Edgar On Thursday, December 26, 2013 2:16:35 PM UTC-5, Brent wrote: On 12/26/2013 1:46 AM, LizR wrote: Interesting, at a brief skim they appear to be suggesting that phenomena like quantum erasure involve rewriting the past, or words to that effect.or have I got that wrong? Yeah, it's sort of like Wheeler's No event is a real event until it's an observed event. They're saying the observation *writes*, not rewrites, the past. But we don't want to leave conscious observation as a mystery; we know that observation by any macroscopic recorder is sufficient to fix the events. I think this can be accommodated in Bruno's theory by looking at it, not as changing or rewriting the past, but as post-selecting the past from the infinite threads of computation. Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/27/2013 10:06 AM, Edgar L. Owen wrote: I generalize Wheeler's statement in my book on Reality to explain how every connected network of events essentially functions as a mini-reality accessible only to event participants of their networks, and it is only through networks connecting through common events that those mini-networks become merged into sharable realities in which events become real because they become observable. So you explain the classical, irreversible nature of observations as a statistical consequence of many interactions, i.e. decoherence. Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Brent, That's not what I say but roughly true. However the classical world is mostly a construct of internal mental models of the external computational reality rather than being an actual external physical world. When we study how minds simulate and model external reality this becomes clear as I explain in Part IV: Mind and Reality of my book. Edgar On Friday, December 27, 2013 5:13:13 PM UTC-5, Brent wrote: On 12/27/2013 10:06 AM, Edgar L. Owen wrote: I generalize Wheeler's statement in my book on Reality to explain how every connected network of events essentially functions as a mini-reality accessible only to event participants of their networks, and it is only through networks connecting through common events that those mini-networks become merged into sharable realities in which events become real because they become observable. So you explain the classical, irreversible nature of observations as a statistical consequence of many interactions, i.e. decoherence. Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Interesting, at a brief skim they appear to be suggesting that phenomena like quantum erasure involve rewriting the past, or words to that effect.or have I got that wrong? -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 26 December 2013 20:17, meekerdb meeke...@verizon.net wrote: There are other viewpoints though. QM makes for some interesting questions about time as raised in this speculative paper by a couple of top experimentalists: http://a-c-elitzur.co.il/uploads/articlesdocs/Elitzur-Dolev13.pdf A few discontents in present-day physics' account of time are pointed out, and a few novel quantum-mechanical results are described. Based on these, an outline for a new interpretation of QM is proposed, based on the assumption that spacetime itself is subject to incessant evolution. ... One of us (AE) owes this insight to a student's question about SchrÄodinger's cat. She argued that, if the box is opened after su±ciently many hours, it should be possible to know whether the cat has been dead or alive during the preceding hours. If it has been alive, it would soil the box and leave scratches on its walls, whereas if it has been dead, it would show signs of decomposition. Here too, the measurement at the moment of opening the box must select not only the cat's state at the moment of opening the box but its entire history within the box. = Interesting, at a brief skim they appear to be suggesting that phenomena like quantum erasure involve rewriting the past, or words to that effect.or have I got that wrong? QM has prompted all sorts of uinintuitive ideas, of course, but I do feel that if one is going to indulge in wild speculation, one should start from a position of understanding what the orthodox view is, as I believe Bruno and Max Tegmark do. I think these people you're citing are also doing that, but from what I have seen so far of Mr Owen's speculations, he hasn't grasped some of the simpler aspects of SR, and hence his ideas don't appear to me to stack up (or maybe I haven't grasped some of the implications of SR, if so I'd be glad to have my mistakes pointed out). This parallels my views on art and music, poetry and writing, as it happens -- that one needs to know the rules before one can break them to good effect -- which may of course be another mistake on my part... -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
2013/12/26 LizR lizj...@gmail.com On 26 December 2013 20:17, meekerdb meeke...@verizon.net wrote: There are other viewpoints though. QM makes for some interesting questions about time as raised in this speculative paper by a couple of top experimentalists: http://a-c-elitzur.co.il/uploads/articlesdocs/Elitzur-Dolev13.pdf A few discontents in present-day physics' account of time are pointed out, and a few novel quantum-mechanical results are described. Based on these, an outline for a new interpretation of QM is proposed, based on the assumption that spacetime itself is subject to incessant evolution. ... One of us (AE) owes this insight to a student's question about SchrÄodinger's cat. She argued that, if the box is opened after su±ciently many hours, it should be possible to know whether the cat has been dead or alive during the preceding hours. If it has been alive, it would soil the box and leave scratches on its walls, whereas if it has been dead, it would show signs of decomposition. Here too, the measurement at the moment of opening the box must select not only the cat's state at the moment of opening the box but its entire history within the box. = Interesting, at a brief skim they appear to be suggesting that phenomena like quantum erasure involve rewriting the past, or words to that effect.or have I got that wrong? QM has prompted all sorts of uinintuitive ideas, of course, but I do feel that if one is going to indulge in wild speculation, one should start from a position of understanding what the orthodox view is, as I believe Bruno and Max Tegmark do. I think these people you're citing are also doing that, but from what I have seen so far of Mr Owen's speculations, he hasn't grasped some of the simpler aspects of SR, and hence his ideas don't appear to me to stack up (or maybe I haven't grasped some of the implications of SR, if so I'd be glad to have my mistakes pointed out). The problem with Mr. Owen (or Roger or Kermit sometimes) is that he asserts things often contrary to known science, use language like though no one seems to have recognized this prior to my exposition in 1997... but his exposition from 1997 is unknown to most on earth but somehow has been recognized to give insightful advancement in science. He uses expressions like XXX *fundamental mistake* while not seeing his owns... That types of vocabulary is the vocabulary of crackpots, not someone open to discussing ideas... These types of persons once coming to the list tends to overwhelm it with massive posting of their revolutionary ideas... I'll pass. Quentin This parallels my views on art and music, poetry and writing, as it happens -- that one needs to know the rules before one can break them to good effect -- which may of course be another mistake on my part... -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out. -- All those moments will be lost in time, like tears in rain. (Roy Batty/Rutger Hauer) -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Brent, Yes, the reuniting is an event, an event like every event that occurs in the present moment. Think about it this way. Assume every observer in the entire universe travels relativistically to meet up at a common location. There will be billions of different clock time readings on their clocks but they will all be together in a single common present moment. Therefore it is clear and inescapable that the present moment is universal and common to every observer in the universe. All the effects of SR and GR affect clock times, but every one of them occurs in a single common present moment they all share. In fact this is completely clear because otherwise they could not even compare clock time results to know they were different. Edgar On Tuesday, December 24, 2013 8:26:00 PM UTC-5, Edgar L. Owen wrote: Liz states that Special relativity shows that there is no such thing as a common present moment. but this is incorrect. Actually special relativity shows exactly the opposite. In my book I explain how this works. It is well known, though little understood, that everything without exception continually travels through spacetime at the speed of light according to its own comoving clock. I call this the STc Principle. This is a well known consequence of special relativity but actually as I point out in my book this is an even more fundamental Principle than Special Relativity and Special Relativity is properly a consequence of it and can be derived from it. What the STc Principle says is that the total velocity through both space and through time of everything without exception is = to the speed of light. This is the reason that time slows on a clock moving with some relative spatial velocity, as Special Relativity tells us. It also demonstrates that the speed of light is properly understood as the speed of TIME. That's what c really is. Light just happens to move entirely in space according to its own comoving clock, therefore its entire spacetime velocity is in space only. Anyway it is precisely this STc Principle that puts both the arrow of time and a privileged present moment on a firm physical basis. Why? Because it requires that everything must be in one particular place in spacetime (the present moment) and moving at the speed of light (the arrow of time). So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, and the reason for a common present moment, though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. Edgar -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/26/2013 1:46 AM, LizR wrote: Interesting, at a brief skim they appear to be suggesting that phenomena like quantum erasure involve rewriting the past, or words to that effect.or have I got that wrong? Yeah, it's sort of like Wheeler's No event is a real event until it's an observed event. They're saying the observation *writes*, not rewrites, the past. But we don't want to leave conscious observation as a mystery; we know that observation by any macroscopic recorder is sufficient to fix the events. I think this can be accommodated in Bruno's theory by looking at it, not as changing or rewriting the past, but as post-selecting the past from the infinite threads of computation. Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/26/2013 5:02 AM, Edgar L. Owen wrote: Brent, Yes, the reuniting is an event, an event like every event that occurs in the present moment. Think about it this way. Assume every observer in the entire universe travels relativistically to meet up at a common location. There will be billions of different clock time readings on their clocks but they will all be together in a single common present moment. Therefore it is clear and inescapable that the present moment No, that's *a* present moment *at a specific place*. It's an event, not a global time. is universal and common to every observer in the universe. All the effects of SR and GR affect clock times, but every one of them occurs in a single common present moment they all share. They don't share it unless they are at the same place in space at the moment, i.e. at an event. Brent In fact this is completely clear because otherwise they could not even compare clock time results to know they were different. Edgar On Tuesday, December 24, 2013 8:26:00 PM UTC-5, Edgar L. Owen wrote: Liz states that Special relativity shows that there is no such thing as a common present moment. but this is incorrect. Actually special relativity shows exactly the opposite. In my book I explain how this works. It is well known, though little understood, that everything without exception continually travels through spacetime at the speed of light according to its own comoving clock. I call this the STc Principle. This is a well known consequence of special relativity but actually as I point out in my book this is an even more fundamental Principle than Special Relativity and Special Relativity is properly a consequence of it and can be derived from it. What the STc Principle says is that the total velocity through both space and through time of everything without exception is = to the speed of light. This is the reason that time slows on a clock moving with some relative spatial velocity, as Special Relativity tells us. It also demonstrates that the speed of light is properly understood as the speed of TIME. That's what c really is. Light just happens to move entirely in space according to its own comoving clock, therefore its entire spacetime velocity is in space only. Anyway it is precisely this STc Principle that puts both the arrow of time and a privileged present moment on a firm physical basis. Why? Because it requires that everything must be in one particular place in spacetime (the present moment) and moving at the speed of light (the arrow of time). So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, and the reason for a common present moment, though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. Edgar -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 27 December 2013 08:16, meekerdb meeke...@verizon.net wrote: On 12/26/2013 1:46 AM, LizR wrote: Interesting, at a brief skim they appear to be suggesting that phenomena like quantum erasure involve rewriting the past, or words to that effect.or have I got that wrong? Yeah, it's sort of like Wheeler's No event is a real event until it's an observed event. They're saying the observation *writes*, not rewrites, the past. But we don't want to leave conscious observation as a mystery; we know that observation by any macroscopic recorder is sufficient to fix the events. I think this can be accommodated in Bruno's theory by looking at it, not as changing or rewriting the past, but as post-selecting the past from the infinite threads of computation. It can also be explained by allowing that quantum objects don't have a built in arrow of time, but can be influenced by future or past events. -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/24/2013 5:26 PM, Edgar L. Owen wrote: Liz states that Special relativity shows that there is no such thing as a common present moment. but this is incorrect. Actually special relativity shows exactly the opposite. In my book I explain how this works. It is well known, though little understood, that everything without exception continually travels through spacetime at the speed of light according to its own comoving clock. I call this the STc Principle. This is a well known consequence of special relativity but actually as I point out in my book this is an even more fundamental Principle than Special Relativity and Special Relativity is properly a consequence of it and can be derived from it. What the STc Principle says is that the total velocity through both space and through time of everything without exception is = to the speed of light. This is the reason that time slows on a clock moving with some relative spatial velocity, as Special Relativity tells us. It also demonstrates that the speed of light is properly understood as the speed of TIME. That's what c really is. Light just happens to move entirely in space according to its own comoving clock, therefore its entire spacetime velocity is in space only. Anyway it is precisely this STc Principle that puts both the arrow of time and a privileged present moment on a firm physical basis. Why? Because it requires that everything must be in one particular place in spacetime (the present moment) and moving at the speed of light (the arrow of time). This is the same approach used by Lewis Carroll Epstein in his excellent little book, Relativity Visualized. His diagrams of spacetime use the usual spacial coordinates, but instead of coordinate time the fourth axis is proper time. Since the proper velocity is always 1, a Lorentz boost just rotates this velocity so is has an increased space component and a reduced time component. As Epstein puts it, The reason we can't go faster than light is that we can't go slower. There is only one speed. Everything, including you, is always moving at the speed of light. However, that doesn't change the fact that space-like separate events can be seen to occur in either order depending on the choice of inertial frame, which is what is meant by the there is no global present. Brent So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, and the reason for a common present moment, though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. Edgar -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out. -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 25 December 2013 14:26, Edgar L. Owen edgaro...@att.net wrote: So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. OK. I was just going by all the physics books I've read, which apparently claim there is no common present time. Obviously that Einstein chap and the authors of those books didn't understand the full implications of special relativity. This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, and the reason for a common present moment, though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. I'm not convinced that there is a big philosophical problem with the arrow of time. If we don't introduce any new physics, the source of the arrow of time can be reduced to two questions - (a) is there any time asymmetry in the laws of physics? (and if there is, is it significant enough to account for eggs forming omelettes, people ageing, sugar dissolving in coffee, and so on) - and (b) are there any boundary conditions on the universe that are sufficient to impose a global time asymmetry on the matter and energy within it? Both these questions can be answered using our present knowledge of physics, and give answers that should be considered first in any discussion of the AOT, before any new physics is introduced. (a) Yes, there is *some* time asymmetry built into the laws of physics - the decay of k-mesons operates in a way that violates time symmetry. All other physical processes, viewed at a short enough distance (or equivalently, a high enough energy) are time-symmetric, as far as we know. It seems unlikely that kaon decay is responsible for the large scale entropy gradient observed in the universe, though it's at least possible it may be coupled to it in some as yet unknown way. (b) the elephant in the room in discussions of the AOT is the big bang, which introduces a global time asymmetry on the entire universe. Consideration of the processes which occurred shortly after the big bang leads to the sources of several forms of known time asymmetry. 1 - the formation of nucleons occurred when the energy density of the universe per unit volume fell below their binding energy due to the cosmic expansion. 2 - the formation of nuclei occurred when the energy density of the universe fell below their binding energy due to the cosmic expansion. 3 - the formation of neutral atoms (so called recombination)occurred when the energfy density of the universe fell below their binding energy due to the cosmic expansion. 4 - Stars and galaxies formed when the density of the universe fell enough for (originally small) density fluctuations to be amplified sufficiently to seed their formation. Hence it seems likely that we can get the AOT purely from the global boundary condition imposed by the expansion of the universe plus some uncontraversial, mainly time-symmetric physics. The formation of bound states like nuclei, atoms and stars can be traced back to the existence of a singularity at one temporal extremity, and the lack of one at the other temporal extremity. Since these bound states are a powerful source of negative entropy, this seems very likely to be the origin of the arrow of time. -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Brent, I agree up until your last sentence. There you ignore the fact that the different orders of events are seen by both observers in the exact same common present moment. This can only be understood when two kinds of time are accepted and the difference between clock time (different for different observers) and P-time, the time of the present moment, are recognized. See my new topic on 2 different kinds of time for an explanation Edgar On Tuesday, December 24, 2013 8:26:00 PM UTC-5, Edgar L. Owen wrote: Liz states that Special relativity shows that there is no such thing as a common present moment. but this is incorrect. Actually special relativity shows exactly the opposite. In my book I explain how this works. It is well known, though little understood, that everything without exception continually travels through spacetime at the speed of light according to its own comoving clock. I call this the STc Principle. This is a well known consequence of special relativity but actually as I point out in my book this is an even more fundamental Principle than Special Relativity and Special Relativity is properly a consequence of it and can be derived from it. What the STc Principle says is that the total velocity through both space and through time of everything without exception is = to the speed of light. This is the reason that time slows on a clock moving with some relative spatial velocity, as Special Relativity tells us. It also demonstrates that the speed of light is properly understood as the speed of TIME. That's what c really is. Light just happens to move entirely in space according to its own comoving clock, therefore its entire spacetime velocity is in space only. Anyway it is precisely this STc Principle that puts both the arrow of time and a privileged present moment on a firm physical basis. Why? Because it requires that everything must be in one particular place in spacetime (the present moment) and moving at the speed of light (the arrow of time). So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, and the reason for a common present moment, though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. Edgar -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
The notion that everything travels through spacetime at the speed of light was popularized by Brian Greene, but it only works if you choose a rather odd definition of speed through spacetime, one which I haven't seen any other physicists make use of. See my post #3 on the thread at http://www.physicsforums.com/showthread.php?t=59901 where I quote Greene's explanation of the math behind his statement and explain why this terminology seems counter-intuitive and not particularly illuminating to me. In any case, you haven't really addressed the basic argument in SR that there is no single objective present--the principle of the relativity of simultaneity. In relativity there are different inertial reference frames, and the two basic postulates of relativity are that the laws of physics must work exactly the same in each inertial frame (so if you were in a windowless room moving inertially in space, there'd be no experiment you could do that would give different results depending on what inertial frame you were at rest in), and the speed of light must be measured to be c in every inertial frame--see https://en.wikipedia.org/wiki/Postulates_of_special_relativity From these two postulates you can derive the fact that different frames must judge simultaneity differently. For example, suppose I am standing on a space station watching you travel by me on a spaceship, with one wall transparent so I can see what's going on inside your ship. Suppose you set off a flash of light at the exact center of your ship, and I measure the time it takes in my frame for the light from the flash to hit the front and back walls of your ship. At the moment the flash happened it was equidistant from the front and back wall, but since the ship is moving forwards in my frame, the back wall is moving *towards* the photons that are heading in the direction of the back wall, while the front wall is moving *away* from the photons that are heading in the direction of the front wall. So, if both sets of photons move at the same speed relative to *my* frame, I must conclude that the photons will reach the back wall at an earlier time than the photons reach the front wall. On the other hand, in your rest frame the ship is simply at rest, so neither wall is moving towards or away from the point where the flash happened, and it's still true that both walls are equidistant from the flash. So if both sets of photons move at the same speed as measured in your frame, then it must be true that in your frame the photons reach the front and back walls simultaneously. So, in this way we can see that the basic postulates imply that different frames cannot agree about the simultaneity of events that happen at different locations in spacetime, like photons hitting two different walls (though all frames do agree about events that coincide in space and time, like two twins comparing ages at the moment they reunite). There's a good youtube video illustrating a somewhat similar argument involving lightning hitting two ends of a moving train at http://www.youtube.com/watch?v=wteiuxyqtoM Anyway, the upshot is that in SR, if Alice and Bob are moving away from each other at some significant fraction of lightspeed, you can have a situation where in Alice's frame, the event of her 40th birthday happens simultaneously with the event of Bob's 32nd birthday, but in Bob's frame the event of Alice's 40th birthday is simultaneous with his own 50th birthday. Unless you are claiming that the same present moment can include both the event of Bob celebrating his 32nd birthday and the event of him celebrating his 50th birthday, it seems that your notion of a privileged present moment must pick one frame's definition of simultaneity out as the correct one while others are incorrect. But all of relativistic physics is derived from the basic postulates which say the laws of physics are the same in all frames, so unless the equations derived this way are fundamentally incorrect, there can be absolutely no experimental way to distinguish one frame as more correct than any other. So, the only way you can have a true present compatible with the experimental accuracy of relativity is to say the there is some kind of metaphysically preferred definition of simultaneity which has no experimental consequences whatsoever. This wouldn't contradict any known physics, but it seems kind of ad hoc...it seems a lot more parsimonious to assume metaphysics lines up with physics in this case, so that a lack of any physically preferred definition of simultaneity would imply a lack of a metaphysically preferred definition too, which would mean the philosophy of time known as eternalism or block time (see https://en.wikipedia.org/wiki/Eternalism_(philosophy_of_time) ) would have to be favored over the philosophy known as presentism which you seem to advocate (see https://en.wikipedia.org/wiki/Presentism_(philosophy_of_time) ) Finally, note that special relativity already has built into it some
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Jesse, Good physics based post. Yes, Brian Greene mentions everything travels through spacetime at the speed of light in both his books but only in passing as a curiosity without recognizing its profound significance. Thanks for your link to your physicsforums post. The meaning of 'speed through time' is actually pretty clear as it's based on the universally accepted fundamental equation for 4-d spacetime in which the t variable has to be multiplied by c to make sense. That has to be accepted if we accept that spacetime is a single 4-dimensional structure which everyone agrees is fundamental to relativity theory. The equation for velocity through spacetime works the same way and has to be accepted for the same reason. Once you accept time as distance along a 4th dimension you have to accept velocity through time and all the math of relativity works fine and is consistent. I don't think there should be any reservations about this. The problem with all your other comments (which I agree with as I scanned them) is they refer to clock time, not the P-time of the present moment. Of course clock time t values vary in a number of ways, but the key insight is they always vary in the exact same present moment which is proved by the time traveling twins reuniting with different clock time t's but always in the exact same present moment. This proves there is a single common universal present moment in which all clock time variations occur. And as you infer proper time is the direct experience of P-time which is the same for all observers even as their clock times are running at different relativistic rates. Edgar On Tuesday, December 24, 2013 8:26:00 PM UTC-5, Edgar L. Owen wrote: Liz states that Special relativity shows that there is no such thing as a common present moment. but this is incorrect. Actually special relativity shows exactly the opposite. In my book I explain how this works. It is well known, though little understood, that everything without exception continually travels through spacetime at the speed of light according to its own comoving clock. I call this the STc Principle. This is a well known consequence of special relativity but actually as I point out in my book this is an even more fundamental Principle than Special Relativity and Special Relativity is properly a consequence of it and can be derived from it. What the STc Principle says is that the total velocity through both space and through time of everything without exception is = to the speed of light. This is the reason that time slows on a clock moving with some relative spatial velocity, as Special Relativity tells us. It also demonstrates that the speed of light is properly understood as the speed of TIME. That's what c really is. Light just happens to move entirely in space according to its own comoving clock, therefore its entire spacetime velocity is in space only. Anyway it is precisely this STc Principle that puts both the arrow of time and a privileged present moment on a firm physical basis. Why? Because it requires that everything must be in one particular place in spacetime (the present moment) and moving at the speed of light (the arrow of time). So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, and the reason for a common present moment, though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. Edgar -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Hi Edgar, thanks for the reply. But do you agree or disagree with the point that since different frames are considered equally valid and they define simultaneity differently, either there would have to be no experimental means to determine which frame's definition of simultaneity is correct (so that the assumption of a true definition of simultaneity would be a purely metaphysical postulate with no experimental significance), or else we would have to discover new physics that violates the two postulates of special relativity? If you disagree I think you are misunderstanding something basic about relativity...on the other hand, if you agree, then which of those two options are you arguing for? Also, what do you think of my point that relativity already has a notion of time separate from proper time, namely coordinate time, and that this allows physicists to make sense of the notion that the two twins meet and compare ages simultaneously even though their ages are different, without requiring us to choose presentism over eternalism/block time? Since the block time view treats time as analogous to a fourth spatial dimension, a spatial analogy might come in handy here. If we have various paths of some kind (roads, say) on a 2D surface, we have a notion of path length between any two points along a given road, which could be measured for example by a car driving along the road with its odometer running. This is analogous to the proper time along a given worldline in relativity. But we could also have a Cartesian coordinate grid on the surface, so that any two points could be labeled with an x and a y coordinate. Then if we have roads that start from the same point A, diverge, then reconverge at some other point B (akin to the world-lines of the twins who depart at some point A in spacetime and reunite at some other point B), we can assign x,y coordinates to both the divergence point and the reconvergence point. If one road was a straight line between A and B while another had some changes in direction, we will see that the straight-line path always has the shorter path length (analogous to the fact that the inertial twin always has a *larger* elapsed proper time--the reason it's larger rather than shorter is because path length for a straight segment of a path in Euclidean space is calculated by sqrt[(change in x coordinate)^2 + (change in y coordinate)^2], whereas proper time for an inertial segment of a path in spacetime is calculated by sqrt[(change in t coordinate)^2 - (change in position coordinates)^2]...the fact that you have a minus sign in the square root rather than a plus sign turns out to imply that in spacetime, a straight path between points is the *longest*, not the shortest). But despite the fact that the two roads have different path lengths between A and B, so that cars that started from A and took each road would reunite with different odometer readings, the two cars do meet at the same x or y coordinate (either one can be treated as analogous to the t-coordinate in spacetime). Clearly this does not imply that other earlier parts of the road have ceased to exist when the cars meet, they're just at a different spatial position; and similarly a block time advocate can say that even though the twins do meet at the same t-coordinate, this doesn't mean that earlier segments of their worldline have ceased to exist as a presentist would believe, they're just at a different position in spacetime than the event of their meeting. Jesse On Wed, Dec 25, 2013 at 2:59 PM, Edgar L. Owen edgaro...@att.net wrote: Jesse, Good physics based post. Yes, Brian Greene mentions everything travels through spacetime at the speed of light in both his books but only in passing as a curiosity without recognizing its profound significance. Thanks for your link to your physicsforums post. The meaning of 'speed through time' is actually pretty clear as it's based on the universally accepted fundamental equation for 4-d spacetime in which the t variable has to be multiplied by c to make sense. That has to be accepted if we accept that spacetime is a single 4-dimensional structure which everyone agrees is fundamental to relativity theory. The equation for velocity through spacetime works the same way and has to be accepted for the same reason. Once you accept time as distance along a 4th dimension you have to accept velocity through time and all the math of relativity works fine and is consistent. I don't think there should be any reservations about this. The problem with all your other comments (which I agree with as I scanned them) is they refer to clock time, not the P-time of the present moment. Of course clock time t values vary in a number of ways, but the key insight is they always vary in the exact same present moment which is proved by the time traveling twins reuniting with different clock time t's but always in the exact same present moment. This proves there is a single common
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
Hi Jesse, Thanks for your thoughtful reply again. Your notion of 'simultaneity' in your first paragraph is clock time simultaneity (same clock time readings), not the common actual present moment of P-time. Big difference. So it doesn't apply to my points. Coordinate time is clock time, proper time is P-time, at least as I interpret it. Note the important, crucial, point that clocks measure only clock time. P-time can't be measured by clocks but it is measurable by Omega, the curvature of the universe (see below). However P-time is experienced, and in fact our consciousness of the present moment is the basic experience of our existence. Yes, block time treats time as a 4th dimension. That's correct so far as it goes, but since only the present moment exists that 4th dimension is actually only a surface, not a whole time dimension extending into past and future. Specifically it's the 4th dimension is only present time moment of our 4-dimensional hypersphere in which our 3-dimensions are the surface, and non-existent past time back to the big bang the radius. It is the continual extension of that radius that is the source of the passage and arrow of time and the present moment. And again most of your last paragraph discusses clock time phenomena rather than the common present moment in which those all play out. Best, Edgar On Tuesday, December 24, 2013 8:26:00 PM UTC-5, Edgar L. Owen wrote: Liz states that Special relativity shows that there is no such thing as a common present moment. but this is incorrect. Actually special relativity shows exactly the opposite. In my book I explain how this works. It is well known, though little understood, that everything without exception continually travels through spacetime at the speed of light according to its own comoving clock. I call this the STc Principle. This is a well known consequence of special relativity but actually as I point out in my book this is an even more fundamental Principle than Special Relativity and Special Relativity is properly a consequence of it and can be derived from it. What the STc Principle says is that the total velocity through both space and through time of everything without exception is = to the speed of light. This is the reason that time slows on a clock moving with some relative spatial velocity, as Special Relativity tells us. It also demonstrates that the speed of light is properly understood as the speed of TIME. That's what c really is. Light just happens to move entirely in space according to its own comoving clock, therefore its entire spacetime velocity is in space only. Anyway it is precisely this STc Principle that puts both the arrow of time and a privileged present moment on a firm physical basis. Why? Because it requires that everything must be in one particular place in spacetime (the present moment) and moving at the speed of light (the arrow of time). So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, and the reason for a common present moment, though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. Edgar -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 26 December 2013 07:23, Jesse Mazer laserma...@gmail.com wrote: The notion that everything travels through spacetime at the speed of light was popularized by Brian Greene, but it only works if you choose a rather odd definition of speed through spacetime, one which I haven't seen any other physicists make use of. Mainly because it doesn't make sense. Speed is change of position with time, hence speed in spacetime equates to the angle a world-line makes relative to some world-line chosen as a basis, e.g. the rest frame of the Hubble flow. Things don't move through space-time, they move through space. They are 4 dimensional objects embedded in space-time. -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/25/2013 12:59 PM, Edgar L. Owen wrote: Coordinate time is clock time, proper time is P-time, at least as I interpret it. Note the important, crucial, point that clocks measure only clock time. ?? Clock is proper-time along the worldline of the clock. P-time can't be measured by clocks but it is measurable by Omega, the curvature of the universe (see below). So you're taking the FRW spherical, homogeneous cosmology as the clock that measures P-time. And then coordinates in which the cosmic microwave background is isotropic are privileged. However P-time is experienced, and in fact our consciousness of the present moment is the basic experience of our existence. But we, the Earth, is not this privileged frame. There is a dipole temperature gradient in the observed CMB due to motion of the Earth. Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/25/2013 2:45 PM, LizR wrote: On 26 December 2013 07:23, Jesse Mazer laserma...@gmail.com mailto:laserma...@gmail.com wrote: The notion that everything travels through spacetime at the speed of light was popularized by Brian Greene, but it only works if you choose a rather odd definition of speed through spacetime, one which I haven't seen any other physicists make use of. Mainly because it doesn't make sense. Speed is change of position with time, hence speed in spacetime equates to the angle a world-line makes relative to some world-line chosen as a basis, e.g. the rest frame of the Hubble flow. Things don't move through space-time, they move through space. They are 4 dimensional objects embedded in space-time. But when you are standing still your time coordinate keeps increasing. Your 4-velocity in your own inertial frame is always (1 0 0 0). Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/25/2013 11:59 AM, Edgar L. Owen wrote: The problem with all your other comments (which I agree with as I scanned them) is they refer to clock time, not the P-time of the present moment. Of course clock time t values vary in a number of ways, but the key insight is they always vary in the exact same present moment which is proved by the time traveling twins reuniting with different clock time t's but always in the exact same present moment. But reuniting in the exact same present moment is not a global time. It's an EVENT and it has no extent in space or time. If the two persons are moving relative to one another then they have different spacelike hypersurfaces of constant time. Einstein rejected the idea of preferring one person's time over the other. You apparently think that one of them might agree with P-time (however that is defined) while the other did not. Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 26 December 2013 15:56, meekerdb meeke...@verizon.net wrote: On 12/25/2013 2:45 PM, LizR wrote: On 26 December 2013 07:23, Jesse Mazer laserma...@gmail.com wrote: The notion that everything travels through spacetime at the speed of light was popularized by Brian Greene, but it only works if you choose a rather odd definition of speed through spacetime, one which I haven't seen any other physicists make use of. Mainly because it doesn't make sense. Speed is change of position with time, hence speed in spacetime equates to the angle a world-line makes relative to some world-line chosen as a basis, e.g. the rest frame of the Hubble flow. Things don't move through space-time, they move through space. They are 4 dimensional objects embedded in space-time. But when you are standing still your time coordinate keeps increasing. Your 4-velocity in your own inertial frame is always (1 0 0 0). If you insist on using this velocity through space-time view, yes. But if you consider yourself to be a worldline then you have no 4-velocity, only a 3-velocity, which is measured as the angle your worldline makes to the vertical axis (modulo the usual caveats about there being no preferred reference frames). Here is a diagram of how time isn't... [image: Inline images 1] And here's a diagram of how it actually is... [image: Inline images 2] ...both are from Chapter 11 of FOR. -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/25/2013 9:15 PM, LizR wrote: On 26 December 2013 15:56, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net wrote: On 12/25/2013 2:45 PM, LizR wrote: On 26 December 2013 07:23, Jesse Mazer laserma...@gmail.com mailto:laserma...@gmail.com wrote: The notion that everything travels through spacetime at the speed of light was popularized by Brian Greene, but it only works if you choose a rather odd definition of speed through spacetime, one which I haven't seen any other physicists make use of. Mainly because it doesn't make sense. Speed is change of position with time, hence speed in spacetime equates to the angle a world-line makes relative to some world-line chosen as a basis, e.g. the rest frame of the Hubble flow. Things don't move through space-time, they move through space. They are 4 dimensional objects embedded in space-time. But when you are standing still your time coordinate keeps increasing. Your 4-velocity in your own inertial frame is always (1 0 0 0). If you insist on using this velocity through space-time view, yes. Hey, it's not something I made up. Check Weinberg's Gravitation and Cosmology. He uses the 4-velocity frequently, e.g. in Ch9 eqn 9.8.1 thru 9.8.6 he writes the T^00 component of the stress energy tensor as rho*U^0U^0, where U^0 is the time-like component of the 4-velocity of a perfect fluid. Robert Wald does much the same in General Relativity. Or look at page 50 of Misner, Thorne, and Wheeler where they write,More fundamental than the components of a vector is the vector itself. It is a geometric object with a meaning independent of all coordinates. Thus a particle has a world line, P(tau), and a 4-velocity U=dP/dtau, that have nothing to do with any coordinates. But if you consider yourself to be a worldline then you have no 4-velocity, only a 3-velocity, which is measured as the angle your worldline makes to the vertical axis (modulo the usual caveats about there being no preferred reference frames). Here is a diagram of how time isn't... Inline images 1 And here's a diagram of how it actually is... Inline images 2 ...both are from Chapter 11 of FOR. First, I said nothing about a present moment; that's Edgar's concept. I referred to the 4-velocity. By treating the velocity as a 3-vector, instead of suppressing the 0-component, the above diagrams do not show how one's clock runs slower relative to the coordinate frame. When you use some of your 4-velocity to move thru space, there is less of it available to move you through time. So when you say it is the angle between the vertical axis and the world line, that's a statement in a specific coordinate system. But one's proper velocity is always 1, independent of coordinates. Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 26 December 2013 19:11, meekerdb meeke...@verizon.net wrote: On 12/25/2013 9:15 PM, LizR wrote: On 26 December 2013 15:56, meekerdb meeke...@verizon.net wrote: On 12/25/2013 2:45 PM, LizR wrote: On 26 December 2013 07:23, Jesse Mazer laserma...@gmail.com wrote: The notion that everything travels through spacetime at the speed of light was popularized by Brian Greene, but it only works if you choose a rather odd definition of speed through spacetime, one which I haven't seen any other physicists make use of. Mainly because it doesn't make sense. Speed is change of position with time, hence speed in spacetime equates to the angle a world-line makes relative to some world-line chosen as a basis, e.g. the rest frame of the Hubble flow. Things don't move through space-time, they move through space. They are 4 dimensional objects embedded in space-time. But when you are standing still your time coordinate keeps increasing. Your 4-velocity in your own inertial frame is always (1 0 0 0). If you insist on using this velocity through space-time view, yes. Hey, it's not something I made up. Check Weinberg's Gravitation and Cosmology. He uses the 4-velocity frequently, e.g. in Ch9 eqn 9.8.1 thru 9.8.6 he writes the T^00 component of the stress energy tensor as rho*U^0U^0, where U^0 is the time-like component of the 4-velocity of a perfect fluid. Robert Wald does much the same in General Relativity. Or look at page 50 of Misner, Thorne, and Wheeler where they write,More fundamental than the components of a vector is the vector itself. It is a geometric object with a meaning independent of all coordinates. Thus a particle has a world line, P(tau), and a 4-velocity U=dP/dtau, that have nothing to do with any coordinates. OK, Brent, my apologies if I have misread you. But you are supporting a view that doesn't make sense in terms of SR - nothing is actually moving through spacetime, and giving (apparent) support to the notion that it is isn't going to help. I don't have most of those books you mention, but I do have Gravitation (which my other half got for his 18th birthday in 1973) open to page 51, box 2.1 - Farewell to ict - and have just had my mind suitably boggled by reading about 4-velocities. Please note, everyone (I'm sure Brent knows this already) that these are NOT velocities *through* space-time, they are handy vectors for working out what is going on at a point along an object's world-line. The object doesn't move through space-time, it exists at various points in space-time which joined together make a 4 dimensional object known as a world line. One can draw vectors at points along this world line and use them to work out its 4-velocity, which I assume is a quantity useful for working out how its clock goes in relation to other objects, and/or how the various Lorentz transformations work - or something along these (world) lines - but this does *not* mean that things are moving through space-time or that there is a common present moment, or that the past doesn't exist, or any of the other things Mr Owen has claimed. I think Brent, who knows all this stuff backwards and sideways, is just toying with us naughty Mr Meeker. -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On 12/25/2013 10:53 PM, LizR wrote: On 26 December 2013 19:11, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net wrote: On 12/25/2013 9:15 PM, LizR wrote: On 26 December 2013 15:56, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net wrote: On 12/25/2013 2:45 PM, LizR wrote: On 26 December 2013 07:23, Jesse Mazer laserma...@gmail.com mailto:laserma...@gmail.com wrote: The notion that everything travels through spacetime at the speed of light was popularized by Brian Greene, but it only works if you choose a rather odd definition of speed through spacetime, one which I haven't seen any other physicists make use of. Mainly because it doesn't make sense. Speed is change of position with time, hence speed in spacetime equates to the angle a world-line makes relative to some world-line chosen as a basis, e.g. the rest frame of the Hubble flow. Things don't move through space-time, they move through space. They are 4 dimensional objects embedded in space-time. But when you are standing still your time coordinate keeps increasing. Your 4-velocity in your own inertial frame is always (1 0 0 0). If you insist on using this velocity through space-time view, yes. Hey, it's not something I made up. Check Weinberg's Gravitation and Cosmology. He uses the 4-velocity frequently, e.g. in Ch9 eqn 9.8.1 thru 9.8.6 he writes the T^00 component of the stress energy tensor as rho*U^0U^0, where U^0 is the time-like component of the 4-velocity of a perfect fluid. Robert Wald does much the same in General Relativity. Or look at page 50 of Misner, Thorne, and Wheeler where they write,More fundamental than the components of a vector is the vector itself. It is a geometric object with a meaning independent of all coordinates. Thus a particle has a world line, P(tau), and a 4-velocity U=dP/dtau, that have nothing to do with any coordinates. OK, Brent, my apologies if I have misread you. But you are supporting a view that doesn't make sense in terms of SR - nothing is actually moving through spacetime, and giving (apparent) support to the notion that it is isn't going to help. I don't have most of those books you mention, but I do have Gravitation (which my other half got for his 18th birthday in 1973) open to page 51, box 2.1 - Farewell to ict - and have just had my mind suitably boggled by reading about 4-velocities. Please note, everyone (I'm sure Brent knows this already) that these are NOT velocities /through/ space-time, they are handy vectors for working out what is going on at a point along an object's world-line. The object doesn't move through space-time, it exists at various points in space-time which joined together make a 4 dimensional object known as a world line. One can draw vectors at points along this world line and use them to work out its 4-velocity, which I assume is a quantity useful for working out how its clock goes in relation to other objects, and/or how the various Lorentz transformations work - or something along these (world) lines - but this does /not/ mean that things are moving through space-time or that there is a common present moment, or that the past doesn't exist, or any of the other things Mr Owen has claimed. I think Brent, who knows all this stuff backwards and sideways, is just toying with us naughty Mr Meeker. There are other viewpoints though. QM makes for some interesting questions about time as raised in this speculative paper by a couple of top experimentalists: http://a-c-elitzur.co.il/uploads/articlesdocs/Elitzur-Dolev13.pdf A few discontents in present-day physics' account of time are pointed out, and a few novel quantum-mechanical results are described. Based on these, an outline for a new interpretation of QM is proposed, based on the assumption that spacetime itself is subject to incessant evolution. ... One of us (AE) owes this insight to a student's question about SchrÄodinger's cat. She argued that, if the box is opened after suąciently many hours, it should be possible to know whether the cat has been dead or alive during the preceding hours. If it has been alive, it would soil the box and leave scratches on its walls, whereas if it has been dead, it would show signs of decomposition. Here too, the measurement at the moment of opening the box must select not only the cat's state at the moment of opening the box but its entire history within the box. = Brent -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at
Re: How the STc principle (special relativity) puts both the arrow of time and a common present moment on a firm physical basis.
On Tue, Dec 24, 2013 at 8:26 PM, Edgar L. Owen edgaro...@att.net wrote: Liz states that Special relativity shows that there is no such thing as a common present moment. but this is incorrect. Actually special relativity shows exactly the opposite. In my book I explain how this works. It is well known, though little understood, that everything without exception continually travels through spacetime at the speed of light according to its own comoving clock. Why are clocks needed? Isn't it enough to say everything travels through spacetime at c? In other words, in one year, every object traces a path one light year long through coordinate time. I call this the STc Principle. Does STc stand for something? This is a well known consequence of special relativity but actually as I point out in my book this is an even more fundamental Principle than Special Relativity and Special Relativity is properly a consequence of it and can be derived from it. What the STc Principle says is that the total velocity through both space and through time of everything without exception is = to the speed of light. Right, this follows from using a Euclidean coordinate system instead of a Minkowski coordinate system. This is the reason that time slows on a clock moving with some relative spatial velocity, as Special Relativity tells us. It also explains clock desynchronization and length contraction. It also demonstrates that the speed of light is properly understood as the speed of TIME. That's what c really is. Light just happens to move entirely in space according to its own comoving clock, therefore its entire spacetime velocity is in space only. Hence why matter contains so much energy: 1 gram of anti-matter (which travels in the opposite direction through the dimension of time) when it hits 1 gram of matter, converts into 2 grams worth of light. Matter trades its velocity through time for velocity through space. Anyway it is precisely this STc Principle that puts both the arrow of time and a privileged present moment on a firm physical basis. Why? Because it requires that everything must be in one particular place in spacetime (the present moment) and moving at the speed of light (the arrow of time). The present moment is only a three dimensional slice through 4-dimensional spacetime. Two co-moving observers exist in different presents, even if they are in the same place and same time. Are you familiar with Reitdijk-Putnam argument ( http://en.wikipedia.org/wiki/Rietdijk–Putnam_argument ) ? I think relativity of simultaneity is proof that there is no such thing as an objective moving present moment. Thus, the perceived flow of time can only be a construction (illusion) within the mind's of the observers. This is what I (and I think Liz) find it confusing when you say all observers exist in the same present. The only way I can interpret that sentence to be true is if you consider the entire block time to be a single present moment, but this is a somewhat radical redefinition of the word present. So exactly contrary to your statement, it is precisely special relativity, properly understood, that puts both the arrow of time and a common present moment on a firm physical basis. Let me ask you a few questions which might help me understand your view: Do you believe past moments in time still exist? Do you think future moments in time already exist? Is Julius Caesar experiencing Ancient Rome (in some location in space-time 2000 ly away? This insight simultaneously solves two of the big problems of the philosophy of science, the source of the arrow of time, This is solved more-or-less by statistics, I think. I don't see how whether past moments in time continue to exist (or not) serves as any justification or explanation for the arrow of time. (What would change regarding the arrow of time if past moments continued to exist?) and the reason for a common present moment, I think the notion of a common present moment is only a loose convention, agreed upon only by some limited group of contemporaries. Other contemporaries, are no less wrong or justified to believe that their (different) time is the present. though no one seems to have recognized this prior to my exposition in 1997 in my paper 'Spacetime and Consciousness'. Do you have a link? Thanks, Jason -- You received this message because you are subscribed to the Google Groups Everything List group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
