J.C.MacSwell Posted June 11, 2018 Posted June 11, 2018 (edited) 32 minutes ago, swansont said: It's more than not knowing, though. There is no way, even in principle, to test to see if it exists. It's not that there is no evidence, it's that there can be no evidence. It has zero impact on physics. Well so far I would say there have been, Michelson-Morely for example...they have just been negative so far or pointing that way. Physics has not been proven to the nth degree. Edited June 11, 2018 by J.C.MacSwell
mistermack Posted June 11, 2018 Posted June 11, 2018 (edited) 39 minutes ago, swansont said: These are not the same arguments. Relativistic symmetry = no preferred frame. You are talking about a frame, and Laughlin is talking about matter. Your very mention of "deeper reality" points toward metaphysics, not physics. It's the wikipedia author who used the phrase "deeper reality". I don't think that Laughlin is talking about ordinary matter. He's talking about the nature of the vacuum, and the existence of an ether of some sort, that if it existed, must have relativistic symmetry. Edited June 11, 2018 by mistermack
swansont Posted June 11, 2018 Posted June 11, 2018 47 minutes ago, mistermack said: It's the wikipedia author who used the phrase "deeper reality". Also you https://www.scienceforums.net/topic/114843-what-is-the-difference-between-a-preferred-state-of-rest-and-a-preferred-state-of-velocity/?page=2&tab=comments#comment-1056340 Quote I don't think that Laughlin is talking about ordinary matter. He's talking about the nature of the vacuum, and the existence of an ether of some sort, that if it existed, must have relativistic symmetry. So? I don't see how that distinction is meaningful. Whatever it is, it has relativistic symmetry, so there is no way you can distinguish between frames. 54 minutes ago, J.C.MacSwell said: Well so far I would say there have been, Michelson-Morely for example...they have just been negative so far or pointing that way. M-M were looking for the aether, before relativity, so that's moot. If one accepts relativity as valid physics, one accepts that there is no detecting an aether. Or, if one can detect an aether, then relativity is invalid. Quote Physics has not been proven to the nth degree. But that's no reason to throw up your hands and not do any physics. You go with the best theories you have.And the best theory we have says there is no aether, one cannot be detected, and it is fantastically successful. The phase space of where it might not work has a lot of zeroes after the decimal, before you get to anything you can notice.
mistermack Posted June 11, 2018 Posted June 11, 2018 8 minutes ago, swansont said: Also you https://www.scienceforums.net/topic/114843-what-is-the-difference-between-a-preferred-state-of-rest-and-a-preferred-state-of-velocity/?page=2&tab=comments#comment-1056340 Yes, but I made it clear I was just referring to what was said in wikipedia. I'm not disputing what you are saying, but I don't think it's a reason not to go there mentally. Nobody knows what's around the corner. Here's another titbit this discussion has thrown up from the web, when I put "river model" into the search : http://www.dailygalaxy.com/my_weblog/2014/06/gravitys-river-new-black-hole-theory-suggests-gravity-is-a-fluid-.html
J.C.MacSwell Posted June 11, 2018 Posted June 11, 2018 13 minutes ago, swansont said: Also you https://www.scienceforums.net/topic/114843-what-is-the-difference-between-a-preferred-state-of-rest-and-a-preferred-state-of-velocity/?page=2&tab=comments#comment-1056340 So? I don't see how that distinction is meaningful. Whatever it is, it has relativistic symmetry, so there is no way you can distinguish between frames. M-M were looking for the aether, before relativity, so that's moot. If one accepts relativity as valid physics, one accepts that there is no detecting an aether. Or, if one can detect an aether, then relativity is invalid. But that's no reason to throw up your hands and not do any physics. You go with the best theories you have.And the best theory we have says there is no aether, one cannot be detected, and it is fantastically successful. The phase space of where it might not work has a lot of zeroes after the decimal, before you get to anything you can notice. Of course. You also don't accept current theory as dogma and stop doing physics either.
Markus Hanke Posted June 12, 2018 Posted June 12, 2018 23 hours ago, mistermack said: It is ironic that Einstein's most creative work, the general theory of relativity, should boil down to conceptualizing space as a medium I disagree with this (and yes, I’m aware you are quoting somebody else here) - firstly, GR is about spacetime, not space. Secondly, it is most certainly not conceptualised as any kind of medium; the nature of spacetime is a collection of events, which are causally related in certain ways. This is very different from any kind of mechanical medium.
swansont Posted June 12, 2018 Posted June 12, 2018 On 6/11/2018 at 12:43 PM, mistermack said: Yes, but I made it clear I was just referring to what was said in wikipedia. You offered it in agreement. On 6/11/2018 at 12:43 PM, mistermack said: I'm not disputing what you are saying, but I don't think it's a reason not to go there mentally. Nobody knows what's around the corner. And the point that has been made is that "going there" is not physics, and will not be physics until one can do an experiment that shows a difference between frames.
J.C.MacSwell Posted June 12, 2018 Posted June 12, 2018 20 minutes ago, swansont said: You offered it in agreement. And the point that has been made is that "going there" is not physics, and will not be physics until one can do an experiment that shows a difference between frames. If you "go there", and set up an experiment that fails to show any difference are you not doing physics?
YaDinghus Posted June 12, 2018 Posted June 12, 2018 (edited) 23 minutes ago, J.C.MacSwell said: If you "go there", and set up an experiment that fails to show any difference are you not doing physics? 23 minutes ago, J.C.MacSwell said: And the point that has been made is that "going there" is not physics, and will not be physics until one can do an experiment that shows a difference between frames. The difference is very nuanced. If it didn't show any difference between frames - of which I have no doubt - then it would have to be an extremely sophisticated experiment that in principle could show that there was a master frame to be of any significance. Since we're talking about science, I tend to say that something is only impossible until someone does it. Coming up with this experiment would require designing a lucid alternative theory to GR, which would be a monumentous feat in its own right. And disproving such a theory with the experiment which was supposed to upheave physics as we know it itself would be irony of... Well, we would have a Shakespeare of Physics Edited June 12, 2018 by YaDinghus
swansont Posted June 13, 2018 Posted June 13, 2018 15 hours ago, J.C.MacSwell said: If you "go there", and set up an experiment that fails to show any difference are you not doing physics? How is that an example of "going there mentally"?
StringJunky Posted June 13, 2018 Posted June 13, 2018 (edited) 6 minutes ago, swansont said: How is that an example of "going there mentally"? Would the Michelson-Morely experiment be an example? Edited June 13, 2018 by StringJunky
swansont Posted June 13, 2018 Posted June 13, 2018 3 minutes ago, StringJunky said: Would the Michelson-Morely experiment be an example? That was an actual experiment, and happened when people thought there was an aether. I take "going there mentally" (in this context) to mean "Let's ignore the physics we know" or possibly "Let's assume that some alternative theory is correct"
StringJunky Posted June 13, 2018 Posted June 13, 2018 Just now, swansont said: That was an actual experiment, and happened when people thought there was an aether. I take "going there mentally" (in this context) to mean "Let's ignore the physics we know" or possibly "Let's assume that some alternative theory is correct" Yeah, I thought that's what you meant. That experiment was consistent for its time. In order to achieve what mistermack wants, you've got to throw away the central tenets of relativity.
swansont Posted June 13, 2018 Posted June 13, 2018 2 minutes ago, StringJunky said: Yeah, I thought that's what you meant. That experiment was consistent for its time. In order to achieve what mistermack wants, you've got to throw away the central tenets of relativity. Exactly. While it's fine to test relativity to see if it holds in new situations and at greater levels of precision (which we do repeatedly), it's quite another thing to make a claim that's contrary to what we've confirmed.
StringJunky Posted June 13, 2018 Posted June 13, 2018 1 minute ago, swansont said: Exactly. While it's fine to test relativity to see if it holds in new situations and at greater levels of precision (which we do repeatedly), it's quite another thing to make a claim that's contrary to what we've confirmed. I don't think its principles will ever be supplanted and any new theory that fills in its sub-atomic gaps must embody them. I did read recently that people were trying to see if they could use the CMBR as an absolute frame. I can't remember the outcomes and consensus on that.
swansont Posted June 13, 2018 Posted June 13, 2018 1 hour ago, StringJunky said: I don't think its principles will ever be supplanted and any new theory that fills in its sub-atomic gaps must embody them. I did read recently that people were trying to see if they could use the CMBR as an absolute frame. I can't remember the outcomes and consensus on that. It's a convenient frame, not an absolute one, as I mentioned earlier
J.C.MacSwell Posted June 13, 2018 Posted June 13, 2018 1 hour ago, swansont said: That was an actual experiment, and happened when people thought there was an aether. I take "going there mentally" (in this context) to mean "Let's ignore the physics we know" or possibly "Let's assume that some alternative theory is correct" I didn't take it that way at all. Mistermack can correct me but I think he meant it as to hold it, or look at it, as a possibility.
StringJunky Posted June 13, 2018 Posted June 13, 2018 3 minutes ago, swansont said: It's a convenient frame, not an absolute one, as I mentioned earlier Right.
swansont Posted June 13, 2018 Posted June 13, 2018 3 minutes ago, J.C.MacSwell said: I didn't take it that way at all. Mistermack can correct me but I think he meant it as to hold it, or look at it, as a possibility. How does one look at it (in a physics sense) if one can't devise an experiment that will confirm it, or a model that distinguishes it?
StringJunky Posted June 13, 2018 Posted June 13, 2018 3 minutes ago, J.C.MacSwell said: I didn't take it that way at all. Mistermack can correct me but I think he meant it as to hold it, or look at it, as a possibility. But that's the same as saying: "Is there a God?"
J.C.MacSwell Posted June 13, 2018 Posted June 13, 2018 2 minutes ago, swansont said: How does one look at it (in a physics sense) if one can't devise an experiment that will confirm it, or a model that distinguishes it? With all due respect that seems backwards. How would you devise, or even give consideration for, an experiment to confirm something if you don't look at it as a possibility first.
swansont Posted June 13, 2018 Posted June 13, 2018 2 hours ago, J.C.MacSwell said: With all due respect that seems backwards. How would you devise, or even give consideration for, an experiment to confirm something if you don't look at it as a possibility first. But we have looked at it, and looked at it carefully, for >100 years. And the framework of the consideration is that there is no way to test for it (i.e. it exists but has relativistic symmetry), and that of some new framework of thought were found it would not change physics at all, since we've already agreed that in this scenario there is no physical test that can distinguish the frame, which is synonymous with saying there is no preferred frame of reference.
studiot Posted June 13, 2018 Posted June 13, 2018 I may be being selfish but I prefer my own frame of reference.
mistermack Posted June 13, 2018 Posted June 13, 2018 12 hours ago, StringJunky said: Yeah, I thought that's what you meant. That experiment was consistent for its time. In order to achieve what mistermack wants, you've got to throw away the central tenets of relativity. Sorry, but that's not right at all. It would only be right, if the one point of view was incompatible with the other. If you postulate that the laws of physics apply equally in every frame, which of course I'm not disputing, then they would inevitably apply in a "real" frame in the same way as every other frame. What's the difference between saying that there is no preferred frame, and saying that there is no preferred frame available? My argument for years now has been that the speed of light RESTRICTS us from observing reality, and relativity is just the consolation prize that we can use to recreate a working model. It's not reality, but it's all we can achieve and we're lucky to have it. Imagine that somebody tomorrow discovered a previously undetected form of light, call it L2. Instead of travelling at c, L2 travelled almost infinitely fast. So as far as we could tell, even from billions of light years away, you were seeing the present. What would that do to relativity? What would you consider reality, what you were seeing with L2, or what you observed with ordinary light? Just because there is no way for US to observe simultaneous events, does that mean there ARE no simultaneous events? It's the unfortunate slow speed of light that's stopping us from observing reality. What we CAN see, is reality for us, it's all we've got, but it's not what's actually out there.
Mordred Posted June 14, 2018 Posted June 14, 2018 (edited) light seed isn't the only process that is affected by the speed limit. All information exchange is affected and under velocity addition even a bullet will be limited to c unless you have a causality violation with time. The mathematics of the transformations do not require light to show the speed limit. That is simply one of the most common examples. An invariant frame as mentioned before as per the M-M experiment would have hydrostatic influences that should be detectable via the M-M experiment. The null results isn't something one can just ignore willy nilly. Edited June 14, 2018 by Mordred
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