• noAxioms
    1.3k
    So you’re saying you have a problem with people fighting for truthleo
    Until you falsify the other interpretation, it's opinion, not truth, and opinion isn't worth the militant fighting.

    Apparently in your view it’s not a good thing to point out falsehoods in the mainstream narrative.
    A great thing if you can, but if you do it by only showing that it contradicts your opinion, then it just makes you look the fool.
    Would you say that relativists attacking ‘absolutists’ aren’t ‘militantly biased’?
    There are some, sure, but at a much lower percentage.

    Personally I would converse on that subject much more calmly if I hadn’t been attacked so many times for simply being a curious and inquiring mind questioning the mainstream narrative and exploring alternative paths, which is what science is supposed to be about in the first place.
    You don't come across as curious. You put up strawman arguments against the truth you believe, and don't bother to actually learn the view you're attacking. Pretty closed minded if you ask me.

    I guess you don’t have a problem with people getting attacked when they question the mainstream narrative.
    But you're not questioning it. You're asserting it to be wrong.

    In this case questioning is not claiming that relativity isn’t consistent with many experiments, it is pointing out that all these experiments can be explained differently, in a much more intuitive way.
    That's not how you've worded your posts. You've asserted that the mainstream view is wrong, and hence must not be consistent with all the experiments. So instead of the rant, chill out and show where it predicts the wrong results. If you can;t, then again chill out and just accept that both views work and neither is necessarily the truth.

    Also note that many ‘relativists’ claim that relativity proves there is no absolute frame.
    Then they're using the same fallacious reasoning as are you. Most of them don't assert this, especially the physicists whose job it is to know relativity. Those physicists may still have their opinions on the matter.

    Meanwhile, I don’t claim that absolute frame theories prove that an absolute frame exists.
    You said you were fighting for the truth. So you seem to at least claim to know the truth without any proof then.

    However it is easier for most people to think in terms of an absolute frame.
    It isn't. The mathematics are furiously more difficult. Imagine a speed limit sign at the side of the road if it was to state the limit in absolute terms. Nobody uses the absolute interpretation to do anything practical. I can think of no examples except a cosmological map of the universe in comoving coordinates. Somehow the inertial frame just doesn't work that scale since no inertial frame foliates all of space.

    No, there's another reason the absolute interpretation might be necessary. I touched on it in a prior post where I mention the three (not two) basic interpretations of the reality of space and time.

    it gets rid of all the confusion surrounding the relativity paradoxes
    There are no paradoxes. Any attempts to present one always involve strawman arguments.
    Relativity is treated as a religion by many of its proponents, that’s a problem.
    * Snort *

    Do you agree that the inertial frame in which the CMB aopears isotropic from here is a different inertial frame that the one where the CMB appears isotropic from a galaxy say 8 billion light years away? — noAxioms
    So? How does that prevent us from selecting the CMBR rest frame here as a preferred frame?
    I said it was the correct choice. I didn't say you shouldn't select it.

    You said you would debunk my statement, and yet when I ask a question, you evade it. Answer the question yes or no or something else. My argument depends on how you answer it. Then you can debunk my argument. You seem to imply 'yes' to that (as you shstraould), but it wasn't clear. If you answer no, then the argument proceeds along the lines of denial of empirical observations. If you say yes, then you should know that the distance between a stationary object here and a stationary object a billion LY away is increasing, which isn't true in any inertial frame.

    If the CMBR rest frame in a galaxy 8 billion light years away ever becomes relevant, then presumably we would have found superluminal signals by then, which would allow us to pick a more accurate preferred frame.
    But they have found 'superluminal' galaxies. The most distant object is something like 32 BLY away, and light from it is 13.4 billion years old. That's means the distance between us and it is increasing at well over twice light speed, despite the fact that both us and it are within a few percent of being stationary.
    It isn't a superluminal signal. The thing was much closer when the light we see now was emitted. That light reaches us now at speed c. Numbers quoted here are all using the absolute interpretation, which I said was useful for such scales.

    Anyway, I called nothing 'strange' — noAxioms

    you get strange effects — noAxioms
    I stand corrected. Yes, I consider a thing slowing down without a force acting on it a strange departure from Newtonian physics, but plenty of GR stuff also departs like that. The conservation of energy thing is a serious problem and either needs to be accounted for or needs to admit that the interpretation does not hold to thermodynamic law,


    I would never have suggested time running more slowly in a muon's own frame. — noAxioms
    So how do you interpret it?
    In the muon's frame, time is not dilated at all since the muon is stationary. I also would not worded it as 'running' since I don't think time is something that 'runs
  • leo
    882
    Until you falsify the other interpretation, it's opinion, not truth, and opinion isn't worth the militant fighting.
    A great thing if you can, but if you do it by only showing that it contradicts your opinion, then it just makes you look the fool.
    You don't come across as curious. You put up strawman arguments against the truth you believe, and don't bother to actually learn the view you're attacking. Pretty closed minded if you ask me.
    But you're not questioning it. You're asserting it to be wrong.
    noAxioms

    So you're not reading or not understanding what I say?

    I'm not saying relativity is false. I'm saying it's not necessarily true. I'm saying there is no proof it is true. I'm saying there are alternative ways to explain all the experiments that are considered tests of special relativity, without invoking relativity. Hence it is false to claim that these experiments prove relativity is true. Basic logic, yet you seem to have a hard time with it.

    There are some, sure, but at a much lower percentage.noAxioms

    A lower percentage doesn't mean there are less of them, seeing as probably 1000 times more people follow the mainstream narrative without ever questioning it. Those who question the mainstream view are relentlessly attacked, just like you are doing now, without focusing on the arguments. Obviously when relativists discuss relativity between themselves they don't attack one another, usually you have those who preach and those who blindly accept what they're told. You're being willfully obtuse about what's going on.

    That's not how you've worded your posts. You've asserted that the mainstream view is wrong, and hence must not be consistent with all the experiments.noAxioms

    Show me where I have asserted that relativity is wrong? Hint: you can't.

    I've said it is a lie to pretend that relativity is proven true. Because, again, alternative theories account for the same experiments just as well. Do you understand this does not imply that relativity is necessarily false? What is it you don't understand about that?

    You said you were fighting for the truth. So you seem to at least claim to know the truth without any proof then.noAxioms

    Look at the scientific literature if you want proofs that one version of the Lorentz aether theory is experimentally equivalent to special relativity. Which implies that there is not only one way to account for the existing experimental evidence. Which implies the experimental evidence doesn't prove relativity is true.

    But if we ever find superluminal signals there would be ways to distinguish them, and then maybe relativity will turn out to be false.

    It isn't. The mathematics are furiously more difficult. Imagine a speed limit sign at the side of the road if it was to state the limit in absolute terms. Nobody uses the absolute interpretation to do anything practical.noAxioms

    The nice thing is the calculations can be simplified a lot by a change of coordinates. Any inertial frame can be picked as the preferred frame to carry out the calculations, it works out the same in the end.

    So in the example of the twins, we can pick the frame of the staying twin as the absolute frame, and then the traveling twin is the one aging more slowly all along. If the real absolute frame is the one of the traveling twin on the way out, then the traveling twin ages more quickly on the first half of the trip, but ages much more slowly on the second half, and the end result we calculate is the same. No matter what the real absolute frame is, the calculated outcome is the same.

    And the advantage is there is no paradox. Even if you call it an apparent paradox and not a real paradox, the point remains that it confuses pretty much everyone, to the point that plenty of papers were written on it in professional journals (and there are many more other paradoxes). Whereas the absolute interpretation is clear, it's the intuitive way people are used to think, there is no "each twin ages more slowly than the other".

    John Stewart Bell advocated teaching special relativity in that way. He called Einstein's approach "pedagogically dangerous". I agree with him. I believe David Mermin also advocates this. Again if you deny that most people are confused about relativity and all its paradoxes (even if you call them not real paradoxes they still confuse most people even when they try hard to resolve them), you're being wilfully obtuse.

    Why push people to study the hard and confusing way instead of the easy way? Especially when they lead to the same observable results? Why make it hard and leave people confused and giving up on understanding the universe? Why tell them that it's the only way to explain the universe and that they have to accept it even if it's confusing? Why tell them the universe is complicated and confusing instead of showing them how it can be explained simply? Like with quantum mechanics people are told to "shut up and calculate". I find this elitist mentality disgusting. And most people aren't aware that alternative explanations exist, because they are never told that, they're just given the confusing mainstream story.

    You said you would debunk my statement, and yet when I ask a question, you evade it..noAxioms

    The "So?" implied a yes, and again so what? If you don't say anything I have nothing to debunk.

    If you say yes, then you should know that the distance between a stationary object here and a stationary object a billion LY away is increasing, which isn't true in any inertial frame.noAxioms

    Well, you should know that if there is an absolute frame, and there is a stationary object in that frame, then the object a billion light years away whose distance is increasing is by definition in motion relative to the frame, it isn't stationary...

    Like I said, if there is an absolute frame, then two frames in relative motion can't both be the absolute frame, so if the absolute frame is the one in which the CMBR is isotropic here then it's not the one where the CMBR is isotropic in other distant galaxies. And even if we can't detect the true absolute frame now, that doesn't mean that we won't in the future depending on what we discover.

    Obviously if you force two frames in relative motion to be the same frame then you get weird effects because that's inconsistent, but I never proposed to do that, you did for some reason.

    But they have found 'superluminal' galaxies. The most distant object is something like 32 BLY away, and light from it is 13.4 billion years old. That's means the distance between us and it is increasing at well over twice light speed, despite the fact that both us and it are within a few percent of being stationary.
    It isn't a superluminal signal. The thing was much closer when the light we see now was emitted. That light reaches us now at speed c.
    noAxioms

    Yea, well these galaxies aren't really 'superluminal', they get this result when they extrapolate Hubble's law to distances where it doesn't apply anymore. See section 2.6.1 in this paper https://arxiv.org/pdf/0707.0380.pdf

    In the muon's frame, time is not dilated at all since the muon is stationary. I also would not worded it as 'running' since I don't think time is something that 'runsnoAxioms

    But you would say that in Earth's frame the muons are time dilated? And if you say time doesn't run, would you say time passes? Flows? How would you say it?
  • leo
    882
    the apparent contradiction that each other's clocks are running slower is just a very simple matter of perspective.

    Here's an easy explanation from the book I'm currently writing:

    [...]
    Edgar L Owen

    By the way that explanation seems to be flawed. It's not really a matter of perspective, as in practice each twin doesn't see how fast the clock of the other twin is ticking. Because in order to know how fast the clock of the other twin his ticking, they have to know how fast the other twin is traveling. And the issue is that fundamentally, each twin doesn't know exactly how fast the other twin is going.

    Because how do they measure each other's velocity? By exchanging light signals. For instance the staying twin would send successive light pulses towards the spaceship and wait for them to be reflected back, and from this he would infer the velocity of the traveling twin as a function of the times of reception of the pulses and as a function of the speed of light on the way out and on the way back.

    But while he can measure the times of reception, he cannot measure the speed of light in each direction (https://en.wikipedia.org/wiki/One-way_speed_of_light), he only knows that the average speed of light on a round-trip is measured to be c, while the unidirectional speed of light could be anything. So the velocity he infers depends on the assumption he makes about the speed of light in each direction.

    If the staying twin assumes that light travels at the same speed in both directions in his frame, then he infers from his measurements that the clock of the traveling twin is ticking more slowly. If the traveling twin makes the same assumption in his own frame, then he infers that the clock of the staying twin is ticking more slowly. Both on the way out and on the way back, and that's what leads to the paradox.

    But if the assumption that light travels at the same speed in both directions in both frames is false, then the paradox disappears. For instance if light travels at c in both directions in the frame of the staying twin, and it travels at c+v and c-v relative to the traveling twin (depending on the direction), then the staying twins infers that the clock of the traveling twin is ticking more slowly, while the traveling twin infers that the clock of the staying twin is ticking more quickly! Both on the way out and on the way back. No more inconsistency.

    And here we see clearly that it is the assumption that light travels at the same speed in all directions in all inertial frames that leads to the twin paradox (and to all other relativity paradoxes). If we don't make that assumption, if instead we assume that there is only one frame in which light travels at the same speed in all directions (just like there is only one frame in which sound travels at the same speed in all directions, the frame where the medium of propagation is at rest), then the paradox disappears, because we haven't introduced something paradoxical (the idea that light travels at the same speed relative to two frames in relative motion).


    Now of course the relativists claim that it isn't a real paradox (if it was relativity would be self-contradictory and worthless), because if they manipulate some mathematical equations in some specific way then they always get the result that the traveling twin has aged less once he returns to Earth. But still there is an uneasiness about it that doesn't go away. At each moment of the trip the staying twin is aging more slowly from the point of view of the traveling twin, and yet when they reunite the staying twin has aged more.

    In order to explain that, they invoke the idea that the calculations always have to be carried out from the same inertial frame all along, which seems arbitrary, and I've never seen them explain intuitively why that is necessary, other than "if we don't do it we don't get the correct result". They may come up with convoluted explanations, but the bottom line is: the postulate of the constancy of the speed of light in all directions in all inertial frames forces them to give up the idea of there being one absolute frame, instead inertial frames are all relative, so measured quantities aren't absolute, they can't be carried from one frame to the other, they are frame-dependent.

    Whereas in the absolute frame interpretation, in which light travels at the same speed in all directions only in one frame, there is no such problem, both twins always agree on which one is aging more slowly than the other. If at each moment of the trip the staying twin is aging more quickly from the point of view of the traveling twin, that's what really happens, when they reunite the staying twin has aged more. We can talk of what things really are like in a frame-independent way, like we've always used to, and that's a huge benefit.

    The paradoxes disappear, and things become intuitive again...
  • noAxioms
    1.3k
    So you're not reading or not understanding what I say?leo
    You're not being very clear about what you're trying to say. I see you starting a rant about fighting for the truth, which says to me that you claim that your view is the truth and everybody is just being dogmatic for not seeing it.

    I'm not saying relativity is false. I'm saying it's not necessarily true.
    ...
    Because, again, alternative theories account for the same experiments just as well.
    Not being clear.
    'Relativity' is the theory, and while science is not is the business of proving anything, the evidence for the theory is overwhelming. It is effectively necessarily true. There is no competing theory.

    What you seem unable to articulate is that the metaphysics behind that theory is open to multiple interpretations (preferred frame vs. any-frame-will-do, and preferred moment vs. block), and thus no one interpretation is necessarily true. With that I agree, and it isn't truth to be fought for, but rather an open-ended philosophical point left to ones personal preference.

    I'm saying there is no proof it is true. I'm saying there are alternative ways to explain all the experiments that are considered tests of special relativity, without invoking relativity.
    Sorry, but even the interpretations with a preferred frame need to invoke relativity theory else they'd predict different things. This is especially true of SR. There is no CMB in SR since it doesn't model our universe. You have to go to GR for that, and GR suggests (wait for it):
    a preferred frame.

    A lower percentage doesn't mean there are less of them, seeing as probably 1000 times more people follow the mainstream narrative without ever questioning it.
    I doubt that very much. The vast majority buy into some sort of single-frame mentality because it works for them. Most of them wouldn't know the first thing about relativity theory or be able to describe how it differs from say a Newtonian view, if they even know what that was. The majority of the relevant physicists and engineers probably hold the mainstream view, but there aren't very many of them. That leaves the fairly small percentage of armchair opinion holders like ourselves on these forums, and among them, it seems split pretty evenly.

    Those who question the mainstream view are relentlessly attacked, just like you are doing now, without focusing on the arguments.
    You seem to be quite focused on perceived attacks and not on any arguments. I don't recall for instance you asking what beef I have with say neo-Lorentz-Ether 'theory'. I put that in quotes since a view that makes no predictions isn't a theory. Not sure what name to give the mainstream view since 'relativity' is the name of the theory, not the metaphysical interpretation. Let's just say 'multi-frame'. You also seem to be in the 3D space camp rather than the 4D spacetime camp. I must admit that the latter term appears frequently in the theory. The mathematics are far simpler in 4 dimensional space than in 3 dimension, and even nLET uses 4D calculations. For instance, I've never seen the twin scenario (a realistic one with Earth not stationary) described using any absolute interpretation.

    Look at the scientific literature if you want proofs that one version of the Lorentz aether theory is experimentally equivalent to special relativity.
    I consider that to be a different metaphysical interpretation of the same theory. He didn't get his name on it only because he didn't publish first, and never completed the general theory. You don't seem to buy into his view since he did not see time flowing/'running' as you seem to. That's why I reference neo-Lorentz-ether theory, which does.

    But if we ever find superluminal signals there would be ways to distinguish them, and then maybe relativity will turn out to be false.
    Lorentz needs superluminal signals? Why? How about quantum entanglement? Some non-local quantum interpretations require them.


    The mathematics are furiously more difficult. Imagine a speed limit sign at the side of the road if it was to state the limit in absolute terms. Nobody uses the absolute interpretation to do anything practical.
    — noAxioms

    The nice thing is the calculations can be simplified a lot by a change of coordinates. Any inertial frame can be picked as the preferred frame to carry out the calculations, it works out the same in the end.
    But that's all that relativity theory (the theory itself) says. The calculations work in any frame.

    So in the example of the twins, we can pick the frame of the staying twin as the absolute frame, and then the traveling twin is the one aging more slowly all along. If the real absolute frame is the one of the traveling twin on the way out, then the traveling twin ages more quickly on the first half of the trip, but ages much more slowly on the second half, and the end result we calculate is the same. No matter what the real absolute frame is, the calculated outcome is the same.
    That sounds exactly like the mainstream view.

    And the advantage is there is no paradox.
    That's right. Never claimed one in either interpretation.
    Even if you call it an apparent paradox and not a real paradox, the point remains that it confuses pretty much everyone, to the point that plenty of papers were written on it in professional journals (and there are many more other paradoxes).
    Agree with that. If they frame it as a paradox, they're misrepresenting the theory or the interpretation. Don't confuse pop articles with science. The Andromeda 'paradox' for instance isn't paradoxical at all unless you say mix interpretations.

    there is no "each twin ages more slowly than the other".
    Yea, like that. That's the misrepresentation I'm talking about. You're dissing an interpretation that you either don't understand or refuse to represent correctly. The theory does not say that each twin ages more slowly than the other.

    If you don't say anything I have nothing to debunk.
    ...
    Well, you should know that if there is an absolute frame, and there is a stationary object in that frame, then the object a billion light years away whose distance is increasing is by definition in motion relative to the frame, it isn't stationary...
    You've contradicted yourself. You agreed that the inertial frame in which the CMB appears isotropic from here is a different inertial frame that the one where the CMB appears isotropic from a galaxy 8 billion light years away (science agrees with that). That isotropic CMB defines being absolutely stationary according to your definition of the preferred frame (known as the comoving frame), and here you say the distant galaxy isn't stationary. You need to fix something (like the statement immediately above) or you've been debunked yourself.


    Like I said, if there is an absolute frame, then two frames in relative motion
    I'm talking about the one absolute frame, and not any other. I'm referencing no other frame.

    [Two frames] can't both be the absolute frame, so if the absolute frame is the one in which the CMBR is isotropic here then it's not the one where the CMBR is isotropic in other distant galaxies.
    This is only true for inertial frames. Are you suggesting now that the preferred frame is inertial? In that case, the CMB is of no help to you since it is isotropic in a different inertial frame at every point in space, and in no inertial frame is there not a point in space from which the CMB appears isotropic to a stationary object.

    You're changing your story, which indicates you're not very familiar with the view you think everybody rejects.

    In the muon's frame, time is not dilated at all since the muon is stationary. I also would not worded it as 'running' since I don't think time is something that 'runs
    — noAxioms

    But you would say that in Earth's frame the muons are time dilated?
    As you say, we can pick Earth's as the absolute frame and say the muons are time dilated, yes.

    And if you say time doesn't run, would you say time passes? Flows? How would you say it?
    Time is a dimension, orthogonal to space, which is why they call it spacetime. Space doesn't flow either. There is no preferred location that is one place, and then somewhere else.
  • Bartricks
    6k
    You either know what you mean and can make it clear, or you don't and cannot.tim wood

    I think I've been very clear. I want to know how the twin case is supposed to provide us with evidence that time is relative. For it seems to me that most of those who reason about these sorts of case commit egregious fallacies.

    So, again, here is my parallel example, one that illustrates, very clearly, just how stupidly people are reasoning about the original twin case.

    My twin is travelling away from me. From my perspective he appears to be getting smaller. From his perspective, I appear to be getting smaller. Conclusion Tim Wood would draw: therefore both of us are actually getting smaller than each other.

    As for what I understand relativity to mean in this context: well, someone who held that time was relative would deny that there is an absolute now. That is, there is no 'now', there is just 'now-for-x'.
  • noAxioms
    1.3k
    But while he can measure the times of reception, he cannot measure the speed of light in each direction, he only knows that the average speed of light on a round-trip is measured to be c, while the unidirectional speed of light could be anything.leo
    I always wondered about this claim. The first speed of light measurement was done using a one way method. It can still be done today with far greater precision. Are you saying Romer did not actually measure light speed, or that the method he used was in some way not one way?
  • tim wood
    8.7k
    I think I've been very clear. I want to know how the twin case is supposed to provide us with evidence that time is relative.Bartricks
    What in the world does "time is relative" mean? Or more accurately, what in the world do you think it means?

    Conclusion Tim Wood would draw: therefore both of us are actually getting smaller than each other.Bartricks
    This is beyond ignorant and worse than stupid because you refuse to access anything that might educate you. Because you won't I suspect it is also useless to reply - but we'll give it a try: travelers moving apart will each seem to the other to be getting smaller, and each will measure the other's clock as running slower. Part of the clock's being measured as running slower is Doppler effect, and part the effects of relativity. There's obviously no accounting for what a person might conclude from this, and relativity on that provides no guidance.

    As for what I understand relativity to mean in this context: well, someone who held that time was relative would deny that there is an absolute now. That is, there is no 'now', there is just 'now-for-x'.Bartricks
    And this is exactly correct.
  • leo
    882
    you claim that your view is the truth and everybody is just being dogmatic for not seeing itnoAxioms

    It is the truth that special relativity is not the only theory consistent with the experiments that are considered tests of that theory, contrary to what is usually claimed. You seem to consider that the Lorentz ether theory is not a different theory but an interpretation of special relativity, I’m going to address that.

    'Relativity' is the theory, and while science is not is the business of proving anything, the evidence for the theory is overwhelming. It is effectively necessarily true. There is no competing theory.

    What you seem unable to articulate is that the metaphysics behind that theory is open to multiple interpretations (preferred frame vs. any-frame-will-do, and preferred moment vs. block), and thus no one interpretation is necessarily true. With that I agree, and it isn't truth to be fought for, but rather an open-ended philosophical point left to ones personal preference.
    noAxioms
    Sorry, but even the interpretations with a preferred frame need to invoke relativity theory else they'd predict different things.noAxioms
    neo-Lorentz-Ether 'theory'. I put that in quotes since a view that makes no predictions isn't a theory. Not sure what name to give the mainstream view since 'relativity' is the name of the theory, not the metaphysical interpretation.noAxioms
    I consider that to be a different metaphysical interpretation of the same theory. He didn't get his name on it only because he didn't publish firstnoAxioms
    Lorentz needs superluminal signals? Why?noAxioms

    The Lorentz ether theory is a theory different from special relativity, it isn’t an interpretation of it. The postulates of special relativity lead to the Lorentz transformation, Einstein called it that way precisely because Lorentz had come up with it before.

    It isn’t a mere matter of philosophical/metaphysical preference though. The two theories are said to be observationally equivalent, this is correct but only to a limited extent.

    Consider that in the Lorentz ether theory, there is only one frame in which light travels at c in all directions, while in other frames this isn’t the case. Whereas in special relativity light travels at c in all directions in all inertial frames. Actually special relativity can be formulated in such a way that light doesn’t travel at c in all directions in all frames, but Einstein believed it didn’t make a difference which is why he and others say that it’s a matter of convention to set the one-way speed of light to c in all directions in all inertial frames.

    However this is correct only as long as nothing travels faster than light! Obviously if we ever encounter superluminal signals, then the one-way speed of light would no more be a convention, it would be experimentally measurable. And it would allow to decide whether there really is an absolute frame or whether all inertial frames are truly relative. The difference wouldn’t be merely metaphysical anymore, because we would have access to new measurements that would distinguish between the two.

    The mere existence of superluminal signals would disprove Einstein’s thesis that the value of the one-way speed of light is a convention.

    But that’s not the only difference between the theories. Consider that special relativity is a principle theory (based on heuristic principles), while the Lorentz ether theory is a constructive theory (provides a picture/mechanism of what is actually thought to be occurring). Another example of a principle theory is thermodynamics, while a corresponding constructive theory is the kinetic theory, which gives a more detailed view and explains the laws of thermodynamics as a consequence of more fundamental phenomena. The kinetic theory can be said to offer a deeper understanding than thermodynamics.

    Special relativity doesn’t attempt to explain what causes time dilation and length contraction, it merely derives them as a consequence of heuristic principles. While the Lorentz ether theory attempts to give the beginning of an explanation. It says that there is a medium that permeates all space, the ether, which represents an absolute frame, and that objects moving within that medium are length contracted and time dilated by a given factor which is a function of their velocity in that medium. The next step would be to understand what is it about that medium that generates such an effect on matter and processes, Lorentz and others had begun working in that direction.

    There is much evidence today that the so-called vacuum of space isn’t empty, it is a medium. And so maybe Lorentz was really on the right track towards a theory more fundamental than special relativity, just like the kinetic theory is more fundamental than thermodynamics.

    There are key differences between special relativity and the Lorentz ether theory, they cannot be said to be two mere interpretations of the same theory. Special relativity doesn’t give any hint as to where to go further towards a more fundamental constructive theory, we’re stuck with its principles (in fact Einstein was initially looking for a constructive theory, but his failure to do so was what led him to formulate a principle theory, which he considered to be something useful to have until we come up with a constructive theory that would explain the same experiments and more). Whereas the Lorentz ether theory opened the path towards a constructive theory.

    And so it really is a sad state of affairs for science that the Lorentz ether theory is ignored, rarely mentioned, or presented as a mere interpretation of special relativity like you do, while it is more than that and it could be so much more than that. But it won’t be as long as it isn’t given the attention it deserves, as long as everyone keeps teaching special relativity alone, as long as everyone remains focused on the principles of special relativity and confused with all its (apparent) paradoxes.

    That leaves the fairly small percentage of armchair opinion holders like ourselves on these forums, and among them, it seems split pretty evenly.noAxioms

    On most physics forums you will find that in most discussions about special relativity most people do not question the mainstream view (that only special relativity can explain all the experiments it explains), and those who do question it are usually labeled crackpots and quickly banned. So much for the scientific spirit of open inquiry.

    For instance, I've never seen the twin scenario (a realistic one with Earth not stationary) described using any absolute interpretation.noAxioms

    I had done the calculations myself some years back, I believe I’ve seen it done in a few papers, but anyway once we realize that by a specific change of coordinate we can treat the Earth as stationary and this greatly simplifies the calculations, there is no need to do the complicated ones all over again every time.

    he did not see time flowing/'running' as you seem to.noAxioms
    Time is a dimension, orthogonal to space, which is why they call it spacetime.noAxioms

    Personally I consider that it is a fallacy to say that time runs/passes/flows, as if time was a physical entity. Change does occur, but time itself is a concept not a physical thing, it is a relative measure of change. For instance to say that some process takes 1 minute is to say that while it takes place, there is another process we call a clock that changes in a specific way that we call 1 minute. When we say that a process is time dilated we’re merely saying that it takes longer than it does in other conditions, relative to a reference process.

    Based on that, I consider it a fallacy to treat 4-dimensional spacetime as anything more than a mathematical concept. Unfortunately many people do believe that spacetime is a real physical thing that really curves. And they believe that because that’s what they’re taught with poor analogies, like the rubber sheet analogy to describe gravity.

    You're dissing an interpretation that you either don't understand or refuse to represent correctly. The theory does not say that each twin ages more slowly than the other.noAxioms

    Not far, it says that at every moment of the trip each twin sees that the other is aging more slowly than themselves.

    And then the real thing that rubs people the wrong way: “at every moment of the trip twin A sees twin B aging more slowly, yet when they reunite twin B has aged more”.

    You've contradicted yourself. You agreed that the inertial frame in which the CMB appears isotropic from here is a different inertial frame that the one where the CMB appears isotropic from a galaxy 8 billion light years away (science agrees with that). That isotropic CMB defines being absolutely stationary according to your definition of the preferred frame (known as the comoving frame), and here you say the distant galaxy isn't stationary. You need to fix something (like the statement immediately above) or you've been debunked yourself.noAxioms

    I concede that the frame in which the CMBR is isotropic here is not necessarily the absolute frame of the whole universe, but I already conceded that. I shouldn’t have said in an earlier post that “in practice an absolute frame can be detected”. It’s simply neat to pick that frame as the preferred frame. And it might be the absolute frame in case the cosmological principle is incorrect. But I didn’t think things through with the CMBR, so you get to win that point if you want. Still there is no proof that there is no absolute frame, personally I believe there is one and eventually we will detect it.

    As you say, we can pick Earth's as the absolute frame and say the muons are time dilated, yes.noAxioms

    And so going back to the fridge example, would you say that the apple in the fridge is time dilated? After all it decays more slowly, just like the muons.

    In the case of the fridge we explain it by saying that the cold slows down the internal processes of the apple. In the case of the muons the common view is to invoke the principles of special relativity, which don’t explain what’s going on but merely account for what’s going on. But now, considering the search for a constructive theory underlying the principles of special relativity, it would be interesting to explore the idea that special relativistic time dilation is a physical slowdown of internal processes due to some effect that is yet to be understood. What do you think?
  • leo
    882
    I always wondered about this claim. The first speed of light measurement was done using a one way method. It can still be done today with far greater precision. Are you saying Romer did not actually measure light speed, or that the method he used was in some way not one way?noAxioms

    Yes the Rømer measurement isn’t a true one-way measurement either, this is actually addressed in the link I mentioned: https://en.wikipedia.org/wiki/One-way_speed_of_light (this is a good Wiki article for once, there aren’t too many like that).

    The Australian physicist Karlov also showed that Rømer actually measured the speed of light by implicitly making the assumption of the equality of the speeds of light back and forth.

    Link to Karlov paper:
    http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1970AuJPh..23..243K


    As a general argument for why we can’t measure the one-way speed of light (my explanation, not taken from the above paper):

    In order to measure the one-way velocity of some thing we need to know the one-way velocity of a signal that we transmit back and forth between that thing and us, but since light is the fastest signal we know and we don’t know the one-way speed of light in the first place, then we can’t measure any one-way velocity with perfect precision, even for slow-moving objects. But while for slow-moving objects the precision is very high (since the average speed of light on a round-trip is much higher), when we attempt to measure the one-way speed of light itself the precision drops to zero, meaning that the one-way speed could be pretty much anything (as long as the two-way average yields c).
  • Bartricks
    6k
    Because you won't I suspect it is also useless to reply - but we'll give it a try: travelers moving apart will each seem to the other to be getting smaller, and each will measure the other's clock as running slower. Part of the clock's being measured as running slower is Doppler effect, and part the effects of relativity. There's obviously no accounting for what a person might conclude from this, and relativity on that provides no guidance.tim wood

    Again: explain how the twin example provides support for relativism about time. You have yet to do so. That is, show me that you are not guilty of the rank stupidity of the person who reasons that the twins are both getting smaller than each other.

    You also assume I am not educated on these matters. Okay, well, this is a philosophy forum - so let's see how well educated you are on the philosophy of time. Just for starters, have you read McTaggart's famous paper? (There will be follow-up questions).
  • Bartricks
    6k
    As for what I understand relativity to mean in this context: well, someone who held that time was relative would deny that there is an absolute now. That is, there is no 'now', there is just 'now-for-x'. — Bartricks

    And this is exactly correct.
    tim wood

    Oh, thanks for confirming that for me! (What you actually mean, by the way, is 'phew - now I know what relativism means - thank you Bartricks for clarifying it for me').

    Er, you realize that concept of time is completely incoherent?
  • Bartricks
    6k
    Thank you for the much-needed sanity.leo

    Likewise!
  • tim wood
    8.7k
    rank stupidity of the person who reasons that the twins are both getting smaller than each other.Bartricks
    "Who reasons that..." Yes, perhaps not rank stupidity, but a path of reasoning that that seems obviously problematic even from the initial statement - not to gainsay any benefits from following it out, part of the practice of good science.

    But what do we say about an individual who seems to decline to distinguish between measurement and understanding what the measurement might mean. Of course two people moving apart will see each other growing smaller, nothing either rank or stupid about that.

    Er, you realize that concept of time is completely incoherent?Bartricks
    Completely incoherent? Really? Completely? I have a wristwatch.

    Of course if Time is completely incoherent, then it's incomprehensible, nor can be spoken of in a reasonable/reasoned way. But we do talk about something and use something called time. Maybe in deference we should call it something else. Suggestion?
  • noAxioms
    1.3k
    The Lorentz ether theory is a theory different from special relativity, it isn’t an interpretation of it. The postulates of special relativity lead to the Lorentz transformation, Einstein called it that way precisely because Lorentz had come up with it before.leo
    Lorentz did not hold to the postulates of relativity. In particular, he denied the first one (that dates back to the time of Galileo). The Galilean principle of relativity states that the laws of physics are the same and can be stated in their simplest form in all inertial frames of reference. Yet LET concludes a violation of that:

    Consider that in the Lorentz ether theory, there is only one frame in which light travels at c in all directions, while in other frames this isn’t the case.
    There you go. That's a violation of the GPoR. Lorentz couldn't accept that principle which is why to my knowledge he never managed to generalize his theory to the actual universe.

    However this is correct only as long as nothing travels faster than light! Obviously if we ever encounter superluminal signals, then the one-way speed of light would no more be a convention, it would be experimentally measurable. And it would allow to decide whether there really is an absolute frame or whether all inertial frames are truly relative.
    OK, I actually agree with this, and have come to a similar conclusion myself. The world of star-trek doesn't work except under an absolute reference system, and since the vast majority of viewers assume such a view, they don't cringe when the Enterprise hits warp speeds.

    But that’s not the only difference between the theories. Consider that special relativity is a principle theory (based on heuristic principles), while the Lorentz ether theory is a constructive theory (provides a picture/mechanism of what is actually thought to be occurring).
    Yes, that being why I call it a metaphysical interpretation. Physics is about what we see (said heuristics), but metaphysics is about what actually is. There is definitely some metaphysical wording in Einstein's theories, especially that taken from Minkowski's work.

    Special relativity doesn’t attempt to explain what causes time dilation and length contraction, it merely derives them as a consequence of heuristic principles.
    That's far more of an explanation than Lorentz's story. If it derives from empirical observation, then it's fully explained.

    While the Lorentz ether theory attempts to give the beginning of an explanation. It says that there is a medium that permeates all space, the ether, which represents an absolute frame, and that objects moving within that medium are length contracted and time dilated by a given factor which is a function of their velocity in that medium. The next step would be to understand what is it about that medium that generates such an effect on matter and processes, Lorentz and others had begun working in that direction.
    I am unclear if this was ever generalized to gravity. How is time dilation say here on Earth explained? I've heard that the ether moves by, giving the impression that it necessarily builds up in places where there is matter, and hence depletes elsewhere. Also how does it explain dilation in a gravity well with no acceleration? I'm inside a hollowed out space inside a planet and my clock runs slower here than out in space, but I'm completely inertial, not accelerating in any way. Which way is the ether going if it is the explanation of the dilation going on there? I ask because the vast majority of our current dilation (compared to a hypothetical stationary clock at zero gravitational potential) is due to this kind of thing.

    Also, I don't see the LET guys explaining the twins using an ether calculation. They all do it the SR way, but keeping to one frame of their choice the whole time.

    everyone remains focused on the principles of special relativity and confused with all its (apparent) paradoxes.
    You seem to know then that it isn't paradoxical.

    That leaves the fairly small percentage of armchair opinion holders like ourselves on these forums, and among them, it seems split pretty evenly.
    — noAxioms

    On most physics forums you will find that in most discussions about special relativity most people do not question the mainstream view
    There are forums that disallow discussions of alternate theories and only exist to give mainstream answers to real questions by people who want to know, and not who want to push their own pet views. If you want to question the mainstream view, these forums are not the place to do it.
    On the other hand, there are forums that are open to it (completely open like Quora where even utterly wrong answers often appear as answers to searched questions) and others that have a separate section to separate mainstream from alternative views. In these forums, the mainstream views are often questioned by more members than supported. I am a moderator on one such forum and the mainstream view seems defended by a small number of people who know it and by several more who don't know it very well, and questioned by countless users that either want real understanding, want to push an alternative (like you), or want to push something of their own.

    Nobody pushing an alternative view gets banned for it. The bans are for abusive language or for purposes of promotion of personal websites. The crackpots often remain, relegated to the children playground. LET is not considered a crackpot view.

    I had done the calculations myself some years back, I believe I’ve seen it done in a few papers, but anyway once we realize that by a specific change of coordinate we can treat the Earth as stationary
    Treating the Earth as stationary when it isn't is valid move because of what Einstein showed.

    and this greatly simplifies the calculations, there is no need to do the complicated ones all over again every time.
    Hence Einstein's being the mainstream view. It indeed simplifies everything.

    Personally I consider that it is a fallacy to say that time runs/passes/flows, as if time was a physical entity.
    There are those that think it does, and that as well is a valid view, although one that Lorentz himself did not seem to hold. He also viewed it as a dimension.

    When we say that a process is time dilated we’re merely saying that it takes longer than it does in other conditions, relative to a reference process.
    Where is your reference process then? How dilated is your kitchen clock? Ever try to compute that?

    Based on that, I consider it a fallacy to treat 4-dimensional spacetime as anything more than a mathematical concept.
    It being a fallacy is not a belief or not. You have to show the logical inconsistency of it. 4-D spacetime is the constructive theory you mentioned, providing an explanation for the dilations and such. LET (or at least the theory Lorentz worked on himself) also posits time as a dimension. nLET does not. You seem to be in the nLET camp then.

    You're dissing an interpretation that you either don't understand or refuse to represent correctly. The theory does not say that each twin ages more slowly than the other.
    — noAxioms

    Not far, it says that at every moment of the trip each twin sees that the other is aging more slowly than themselves.
    Wrong again. In order to make any determination about relative ages, a frame needs to be selected. If they happen to choose different frames, then the results may differ. They each could choose different frames for example and compute that the other twin is always aging faster than themselves. The question of which is older is a frame dependent question. You know this, and yet you misrepresent what the theory says by omitting frame references in a statement that references multiple frames. That's a strawman tactic, or fallacious reasoning.

    And then the real thing that rubs people the wrong way: “at every moment of the trip twin A sees twin B aging more slowly, yet when they reunite twin B has aged more”.
    More strawman. It isn't true since the turnaround time is not considered in the above statement, and also the frame references (there are multiple frames again) are omitted. You seem to do this deliberately since you know better. Are you really suggesting that the mainstream view is contradictory or are you just pretending to be stupid when it suits your purposes?

    I concede that the frame in which the CMBR is isotropic here is not necessarily the absolute frame of the whole universe, but I already conceded that. I shouldn’t have said in an earlier post that “in practice an absolute frame can be detected”. It’s simply neat to pick that frame as the preferred frame.
    If you mean the inertial frame in which the CMBR is isotropic here, that is not a valid candidate for the preferred frame of the universe since no inertial frame foliates all of spacetime. In other words, galaxies like GN-z11 (something we can see) does not even exist in that inertial frame since it is moving at well over light speed and thus hasn't yet been born. Inertial frames are really only locally valid and do not correspond to curved space. Most of the absolutist theories choose the comoving frame as the absolute frame. Even GR does, it being for instance the only frame in which the expansion rate of the universe is the same at every spatial point in the frame.

    Still there is no proof that there is no absolute frame, personally I believe there is one and eventually we will detect it.
    There seems to be the one choice, making it quite detectable. It is objective in that any observer anywhere in the universe would agree with the choice, and they certainly wouldn't agree with the one you chose.

    And so going back to the fridge example, would you say that the apple in the fridge is time dilated?
    No. I put a clock in there and it still paces the one on the outside. That's empirical evidence against the dilation explanation of the apple rotting.

    it would be interesting to explore the idea that special relativistic time dilation is a physical slowdown of internal processes due to some effect that is yet to be understood. What do you think?
    But they've already done that, in two different ways (geometry and ether). The geometry method for instance explains (and is not just a mathematical convenience) why the height of a flag pole can be taller or shorter depending on your choice of the orientation of the 'up' dimension. That is physical length contraction without any change to the proper dimensions of the pole. That's essentially the contructive explanation behind dilation: recognition that measurements of any one dimension depends on the choice of orientation of the coordinate system, without any physical change to the proper properties of the object being measured.
  • leo
    882
    I want to know how the twin case is supposed to provide us with evidence that time is relative. For it seems to me that most of those who reason about these sorts of case commit egregious fallacies.Bartricks
    As for what I understand relativity to mean in this context: well, someone who held that time was relative would deny that there is an absolute now. That is, there is no 'now', there is just 'now-for-x'.Bartricks

    Indeed the twin paradox doesn’t prove that there is no absolute ‘now’. First of all it is a thought experiment based on the postulates of special relativity (not an actual experiment that has been carried out), and these postulates imply that there is no absolute ‘now’, so the description of what happens in the frame of each twin already presupposes that there is no absolute ‘now’. So concluding from the twin paradox that there is no such thing as an absolute ‘now’ would be a circular reasoning.

    Another thing to keep in mind is that even if that experiment was carried out, each twin wouldn’t see exactly how fast the clock of the other twin is ticking. Because if the traveling twin sends a light pulse every second towards the staying twin, the staying twin doesn’t receive a pulse every second (even if there was no time dilation) because the traveling twin is moving away from the staying twin. And so in order to infer how fast the clock of the other twin is ticking they have to know how fast light goes in one direction, but as I explained in a post above this one-way speed of light can’t be measured without using faster-than-light signals which we don’t have.

    So what each twin infers depends on what they assume about the one-way speed of light. If they each assume that this one-way speed is the same in all directions in each of their frame, then each of them infers that the clock of the other twin is ticking more slowly. If they make different assumptions they would infer otherwise, they might both say that the clock of the other twin is ticking more quickly, or they might agree that one clock is ticking more slowly than the other but they could disagree about the magnitude.

    As we see the assumption they make about the one-way speed of light changes what they infer to happen, so strictly speaking we can’t say that each twin ‘sees’ time dilation. But they do see the clock of the other ticking more slowly from the mere fact that they are moving away from each other (as every successive pulse has more distance to cover).

    But there are experiments that do show that an atomic clock doesn’t tick at the same rate depending on how fast it moves. Just like there are experiments that show that an apple doesn’t decay at the same rate depending on how cold it is. And indeed neither of them implies that there is no absolute ‘now’, they can both be interpreted as internal processes running at a different rate in different conditions (relative to some reference process) without contradicting absolute simultaneity.
  • noAxioms
    1.3k
    Yes the Rømer measurement isn’t a true one-way measurement either, this is actually addressed in the link I mentioned: https://en.wikipedia.org/wiki/One-way_speed_of_light (this is a good Wiki article for once, there aren’t too many like that).

    The Australian physicist Karlov also showed that Rømer actually measured the speed of light by implicitly making the assumption of the equality of the speeds of light back and forth.
    leo
    Yes, it says that, despite no signal going back. Only forth.
    At no point does that page say that the measurement was invalid (cannot be done to arbitrary precision today) or that it in fact involved a round trip signal of some kind.

    In order to measure the one-way velocity of some thing we need to know the one-way velocity of a signal that we transmit back and forth between that thing and us
    This says that in order to know X, you already need to know X. I suppose that's arguably true in this case.


    but since light is the fastest signal we know and we don’t know the one-way speed of light in the first place, then we can’t measure any one-way velocity with perfect precision, even for slow-moving objects.
    We're not asking for perfect precision. Romer was off by quite a bit mostly because of a poor measurement of Earth's orbital radius, something not trivial to measure in the day. The most accurate clock at the time was a sundial. Still, the method works today and easily gets several digits of accuracy. Perfection? No.

    But while for slow-moving objects the precision is very high (since the average speed of light on a round-trip is much higher), when we attempt to measure the one-way speed of light itself the precision drops to zero, meaning that the one-way speed could be pretty much anything (as long as the two-way average yields c).
    There was no two-way measurement. That's the whole point.
  • Bartricks
    6k
    Gibberish. You've not answered my questions. You haven't read McTaggart, have you? So you don't know about the philosophy of time (for philosophy of time really begins with his famous argument). You can't show me why it is no less stupid to conclude that the twins paradox implies that relativism about time is true than to conclude that relativism about size is true, or to conclude that time flows more slowly in fridges (here's the simple reason for that: there's no difference in the reasoning, and those who think time is relative on the basis of the twin paradox are being stupid).
  • tim wood
    8.7k
    You have not answered mine about the what time being relative means. Relative to what? If not relative, then what? And if referred to something else, then what? Meanwhile you claim.

    MacTagggart? Read. https://plato.stanford.edu/entries/mctaggart/#UnrTim

    But you say time is unreal, that time is completely incoherent. You'll have to own that yourself. Make your case. After all, your opponent is only a wristwatch.
  • Bartricks
    6k
    You have not answered mine about the what time being relative means.tim wood

    er, yes I did. Here:

    Here:
    tim woodAs for what I understand relativity to mean in this context: well, someone who held that time was relative would deny that there is an absolute now. That is, there is no 'now', there is just 'now-for-x'. — Bartricks

    And this is exactly correct. — tim wood
    Bartricks

    And why are you pointing me to a Stanford encyclopedia entry? The question is have YOU read McTaggart?

    You don't know your stuff, do you? You haven't even read McTaggart. All you've done is watch some youtube videos made by physicists or wannabe physicists who are as ignorant as you are about the philosophy of time.

    Look, anyway, you're too ignorant to be worth discussing this matter with any further. Tara.
  • Bartricks
    6k
    But you say time is unreal, that time is completely incoherent. You'll have to own that yourself. Make your case. After all, your opponent is only a wristwatch.tim wood

    I also didn't say that. So again, well done for paying no attention whatsoever. I think time is real. I don't think it is relative. I think the idea that it is relative is incoherent. But I think time is real (unlike McTaggart). I mentioned McTaggart because contemporary philosophy of time begins with him, and I think you haven't read him. (Yet you seem to think that you're up on the subject and that it is I who does not know his stuff).

    But I am not going to explain why 'time is relative' doesn't make sense to someone who wouldn't know sense from his elbow.
  • leo
    882
    Lorentz did not hold to the postulates of relativity.noAxioms

    I didn’t claim he did, you were saying that the Lorentz ether theory came after special relativity, I was pointing out that’s not the case.

    Yes, that being why I call it a metaphysical interpretation. Physics is about what we see (said heuristics), but metaphysics is about what actually is.noAxioms

    You would have called the kinetic theory of gases a metaphysical interpretation of thermodynamics, back when molecules hadn’t been observed yet. We shouldn’t pretend that we already see everything that we can see.

    That's far more of an explanation than Lorentz's story. If it derives from empirical observation, then it's fully explained.noAxioms

    So in the same way you consider that thermodynamics provides far more of an explanation than the kinetic theory? If scientists had contented themselves with apparent laws without looking to explain why these laws are accurate, science wouldn’t have advanced very far.

    I am unclear if this was ever generalized to gravity. How is time dilation say here on Earth explained?noAxioms

    Some people have done that, here is an example: https://ilja-schmelzer.de/gravity/

    Or if you assume that gravity is an ether flow you can recover many general relativistic predictions. So you can explain time dilation on Earth in terms of this ether flow (since in the Lorentz ether theory processes are time dilated when they are moving in the ether). That’s just an example, point is it can be done, and not necessarily in a complicated way.

    Also how does it explain dilation in a gravity well with no acceleration? I'm inside a hollowed out space inside a planet and my clock runs slower here than out in space, but I'm completely inertial, not accelerating in any way. Which way is the ether going if it is the explanation of the dilation going on there? I ask because the vast majority of our current dilation (compared to a hypothetical stationary clock at zero gravitational potential) is due to this kind of thing.noAxioms

    You mean if you’re at the center of the planet? Indeed this might be a problem of the ether flow theory, I would have to think more about it. In any case not much research has been done in that direction, but I’m confident it should be possible to come up with a simple and accurate theory of gravitation without invoking curved spacetime.

    Also, I don't see the LET guys explaining the twins using an ether calculation. They all do it the SR way, but keeping to one frame of their choice the whole time.noAxioms

    As I said it can be done, it’s just tedious. Once you realize that the result comes out the same no matter what the real absolute frame is, then there is no need to pick an arbitrary frame that makes calculations complicated, might as well pick one that simplifies them. Which again does not imply that there is no difference between the Lorentz ether theory and special relativity, as I explained.

    I am a moderator on one such forum and the mainstream view seems defended by a small number of people who know it and by several more who don't know it very well, and questioned by countless users that either want real understanding, want to push an alternative (like you), or want to push something of their own.

    Nobody pushing an alternative view gets banned for it. The bans are for abusive language or for purposes of promotion of personal websites. The crackpots often remain, relegated to the children playground. LET is not considered a crackpot view.
    noAxioms

    Okay, maybe I’ve been on the wrong forums then, the few ones I used were extremely dogmatic and totally not open to alternative ideas.

    Treating the Earth as stationary when it isn't is valid move because of what Einstein showed.noAxioms

    The validity of doing that can be derived from the Lorentz transformation itself, which existed before special relativity.

    Where is your reference process then? How dilated is your kitchen clock? Ever try to compute that?noAxioms

    That wasn’t my point, let’s say you pick the kitchen clock as a reference process, and you compare some process A to that reference process. Then you find out that under some conditions that process A runs more slowly compared to the reference process, we say that process A is time dilated, that’s all.

    Hence Einstein's being the mainstream view. It indeed simplifies everything.noAxioms

    It doesn’t simplify the understanding as it confuses the vast majority of people. It’s pedagogically much simpler to retain the view that there is an absolute frame like we’re used to, then show that no matter which inertial frame is the absolute one we still get the same result, then use that to simplify the calculations, without going the next step and claim that the absolute frame doesn’t exist and give up our intuitive understanding. If Einstein’s view simplified everything, people wouldn’t still be confused about the twin paradox and others a century later. There is no such confusion when we assume an absolute frame.

    It being a fallacy is not a belief or not. You have to show the logical inconsistency of it. 4-D spacetime is the constructive theory you mentioned, providing an explanation for the dilations and such.noAxioms

    I didn’t claim spacetime is inconsistent, I said that it is a mathematical concept, not a physical thing. Well there is no evidence that it is a physical thing, so there is no evidence that it is a physical thing that curves. It could be a constructive theory if we had actually detected a 4-dimensional thing that curves, but obliviously we haven’t. Stuff like gravitational lensing isn’t evidence at all of such curvature, considering that we don’t have to assume that light always travels in straight lines.

    LET (or at least the theory Lorentz worked on himself) also posits time as a dimension. nLET does not. You seem to be in the nLET camp then.noAxioms

    I’m not sure in what way you distinguish LET and nLET, but as I said I consider time to be a concept of the mind, a tool of thought. I don’t see time and change as the same thing, time refers to a measure of change, it isn’t change itself.

    The question of which is older is a frame dependent question. You know this, and yet you misrepresent what the theory says by omitting frame references in a statement that references multiple frames.noAxioms

    I said “at every moment of the trip each twin sees that the other is aging more slowly than themselves”, the frame references lie in the “sees”. Each twin sees, but the twins aren’t in the same frame, so it is implied that what they see is frame dependent, they see that from their own frame.

    It isn't true since the turnaround time is not considered in the above statement, and also the frame references (there are multiple frames again) are omitted. You seem to do this deliberately since you know better. Are you really suggesting that the mainstream view is contradictory or are you just pretending to be stupid when it suits your purposes?noAxioms

    I said: “at every moment of the trip twin A sees twin B aging more slowly, yet when they reunite twin B has aged more”, are you really claiming that’s false? There can be zero turnaround time if you invoke triplets instead of twins.

    I’m not suggesting special relativity is self-contradictory, I specifically said it isn’t, I’m merely suggesting what I’ve been saying since the beginning, that it is extremely confusing (whereas there is another theory that isn’t), and you’re the one pretending there is nothing confusing about it.

    From the point of view of the traveling twin, the clock of the staying twin is ticking more slowly, on the first half and on the second half of the trip, you can even simulate an instantaneous turnaround using a second spaceship. Yet when they reunite the clock of the staying twin has ticked more. Sure you can explain that by invoking different frames, the point is it’s extremely confusing. Whereas in the absolute view the clock of the staying twin is not ticking more slowly at every moment.

    If you mean the inertial frame in which the CMBR is isotropic here, that is not a valid candidate for the preferred frame of the universe since no inertial frame foliates all of spacetime. In other words, galaxies like GN-z11 (something we can see) does not even exist in that inertial frame since it is moving at well over light speed and thus hasn't yet been born.noAxioms

    As I said, there are no real superluminal galaxies, I gave a link to a paper explaining that. The Hubble law doesn’t apply to arbitrarily large distances. If you assume it does then you get superluminal velocities. Just like if you assume that the speed of a car increases by 10m/s every second eventually that car will exceed the speed of light, that doesn’t mean it ever gets there. You can very well pick a global frame in which nothing is superluminal.

    See that’s the kind of confusing stuff with the mainstream view, on the one hand they say nothing exceeds the speed of light, on the other hand they extrapolate Hubble’s law to arbitrarily large distances, and then they get superluminal galaxies, and people get confused. Don’t make that unwarranted extrapolation and you don’t get superluminal galaxies, simple.

    No. I put a clock in there and it still paces the one on the outside. That's empirical evidence against the dilation explanation of the apple rotting.noAxioms

    Or the apple is time dilated in the fridge but not the clock. Have you tried accelerating an apple to a high velocity to see if it decays more slowly? Maybe the clock gets time dilated but not the apple.

    Also have we ever tested if a mechanical clock gets time dilated at high velocities? To my knowledge only atomic clocks have been tested. Sure they’re more accurate, but then maybe their time dilation has to do with their internal processes, there is no evidence that everything gets time dilated due to velocity.

    The geometry method for instance explains (and is not just a mathematical convenience) why the height of a flag pole can be taller or shorter depending on your choice of the orientation of the 'up' dimension. That is physical length contraction without any change to the proper dimensions of the pole.noAxioms

    Well a flag pole can certainly appear differently depending on how you look at it, that doesn’t imply that the flag pole physically changes when you do that, unless again you’re assuming arbitrarily that there is not one reality but one reality for each frame.

    Also I don’t see what that has to do with seeing time dilation as a manifestation of a slowdown of internal processes. Indeed Lorentz and others had begun looking in that direction, but not much research has been done on that since.
  • leo
    882
    Yes, it says that, despite no signal going back. Only forth.
    At no point does that page say that the measurement was invalid (cannot be done to arbitrary precision today) or that it in fact involved a round trip signal of some kind.
    noAxioms

    Did you read the paper of Karlov? In the Rømer measurement at some point an implicit assumption is made that light travels at the same speed in both directions, it’s not easy to see.

    This says that in order to know X, you already need to know X. I suppose that's arguably true in this case.noAxioms

    That would be a tautology. Without instantaneous signals we can’t measure any one-way velocity with perfect precision.

    Consider how you might measure a one-way velocity. You will realize that the best precision you can attain depends on the two-way velocity of the fastest signal you have. There is no way around that.

    There was no two-way measurement. That's the whole point.noAxioms

    Are you still claiming that the one-way speed of light has been measured? If so there’s something you haven’t understood. Look deeply into it, you will realize it can’t be measured with any precision, as long as we don’t have faster-than-light signals.



    Well I’m probably not going to be available for a while, I’d like to discuss all of this more, but sadly we’re not being paid to discuss that, we mostly get paid to slave away while contributing to the destruction of the planet in some way, so I guess I’ll join the herd, I tried to escape it but that didn’t work. Gonna be a slave trying to buy his freedom, cause that’s what this world is about really. I wish things were different. But people don’t wake up, so things don’t change, and I can’t change it all on my own. /rant
  • noAxioms
    1.3k
    You would have called the kinetic theory of gases a metaphysical interpretation of thermodynamics, back when molecules hadn’t been observed yet.leo
    I think not since that theory makes predictions. I suppose that explains the hunt for the ether, even though I don't think it is posited to be detectable.

    That's far more of an explanation than Lorentz's story. If it derives from empirical observation, then it's fully explained.
    — noAxioms

    So in the same way you consider that thermodynamics provides far more of an explanation than the kinetic theory?
    About the same actually. The explanation is that light actually goes the same speed in any frame, and doesn't just appear to. That explanation is all that is needed. It isn't provable of course, but neither is the alternate (and more complicated) explanation.

    Or if you assume that gravity is an ether flow you can recover many general relativistic predictions. So you can explain time dilation on Earth in terms of this ether flow (since in the Lorentz ether theory processes are time dilated when they are moving in the ether). That’s just an example, point is it can be done, and not necessarily in a complicated way.
    ...
    Indeed this might be a problem of the ether flow theory, I would have to think more about it. In any case not much research has been done in that direction, but I’m confident it should be possible to come up with a simple and accurate theory of gravitation without invoking curved spacetime.
    Keep in mind I'm just asking here since I'm not totally familiar. If the ether moves/flows, where does the ether go when it gets to say the center of say Earth?

    Also how does it explain dilation in a gravity well with no acceleration? I'm inside a hollowed out space inside a planet and my clock runs slower here than out in space, but I'm completely inertial, not accelerating in any way. Which way is the ether going if it is the explanation of the dilation going on there? I ask because the vast majority of our current dilation (compared to a hypothetical stationary clock at zero gravitational potential) is due to this kind of thing.
    — noAxioms

    You mean if you’re at the center of the planet?
    No, the question above talks about being in a dense hollow shell, a region of a flat gravitational field (no acceleration, but still in a well). Let's assume the ball is stationary so the dilation is completely due to gravity and not the ball moving through the ether or being in an acceleration field.

    Also, I don't see the LET guys explaining the twins using an ether calculation. They all do it the SR way, but keeping to one frame of their choice the whole time.
    — noAxioms

    As I said it can be done, it’s just tedious.
    That was my point. I'm not suggesting it can't be done, but the tedium is part of why it isn't the mainstream view.

    Okay, maybe I’ve been on the wrong forums then, the few ones I used were extremely dogmatic and totally not open to alternative ideas.
    I've been on some of those like thephysicsforum.com . I abandoned it due to the open hostility displayed not only to those pushing nonsense, but the uninformed asking genuine questions. My post count there is still a single digit I think.

    The validity of doing that can be derived from the Lorentz transformation itself, which existed before special relativity.
    I read that actually, so agree.

    Where is your reference process then? How dilated is your kitchen clock? Ever try to compute that?
    — noAxioms
    That wasn’t my point
    No, but it is sort of one of my points. All clocks anywhere are dilated, no matter their position or velocity. They never compute how dilated these clocks are. Nothing exact is asked for. A single digit of precision would be nice. You'd think the 'time flows' proponents would want to know the objective rate of time flow, but they seem to avoid it like it's something embarrassing.

    Hence Einstein's being the mainstream view. It indeed simplifies everything.
    — noAxioms
    It doesn’t simplify the understanding as it confuses the vast majority of people.
    I am inclined to agree with that. But it's the physicists and engineers that actually need to work with the theory and not just comprehend a description of a couple paragraphs, and to that end the mainstream view is, well, complete for one thing. I suppose Lorentz's theory has been generalized then? I wonder how black holes are handled since they don't seem to exist under LET. That's not much of a knock against it since I could probably argue similarly for any interpretation.

    It’s pedagogically much simpler to retain the view that there is an absolute frame like we’re used to, then show that no matter which inertial frame is the absolute one we still get the same result, then use that to simplify the calculations, without going the next step and claim that the absolute frame doesn’t exist and give up our intuitive understanding.
    But the mainstream view is the same in that way: Any frame can be used and the calculations are simple, and if you choose a different frame as the one to use, then a different person is dilated more. We're back to the same concepts that need teaching in both cases.

    If Einstein’s view simplified everything, people wouldn’t still be confused about the twin paradox and others a century later. There is no such confusion when we assume an absolute frame.
    Einstein's view doesn't suggest you complicate things by computing everything in different frames. It is equally simple if you stick to one like you should in such an exercise. The confusion occurs when the situation is deliberately described in mixed frames. Look at the OP of this thread where Mike is doing exactly that: Describing everything in from an idealistic mixed-frame point of view where distant people physically age backwards and such. It's not wrong, but it omits a lot of implicit assumptions and thus is nothing but confusing. He words it like my age is caused by the actions of somebody far from me, which is nonsense.

    I didn’t claim spacetime is inconsistent, I said that it is a mathematical concept, not a physical thing.
    That's your belief, and that's fine. I happen to prefer the view that the physical thing is just like that. I personally find the 3D view logically inconsistent, but relativity theory has nothing to do with that.

    LET (or at least the theory Lorentz worked on himself) also posits time as a dimension. nLET does not. You seem to be in the nLET camp then.
    — noAxioms
    I’m not sure in what way you distinguish LET and nLET,
    neo Lorentz ether theory, that which has evolved from his work by others. The big change was the assertion of the 3D flowing time view, the thing that MTaggart supposedly 'disproved' according to Bartricks' post above. I'm personally unimpressed with the argument. Point is, I am unaware that Lorentz himself supported that. Maybe I'm wrong. His was a preferred frame but not preferred moment model.

    I said “at every moment of the trip each twin sees that the other is aging more slowly than themselves”
    the frame references lie in the “sees”.
    If the twins are approaching each other, they see the other aging faster. Yes, that's doppler, so 'sees' is a misleading choice of verbs. What each actually does is compute the age of the other, and in order to do that, each needs to select a frame, and if they select different frames (there is no reason they need to), then they're going to get different answers of course. Your statement omitted the choice of frames they made, and hence is using obfuscating language. The fact is that they're incapable of determining the age of somebody not in their presence. You know that, but your statement suggests they can. Take away the obfuscating language and the attempted paradox vanishes.

    It isn't true since the turnaround time is not considered in the above statement, and also the frame references (there are multiple frames again) are omitted. You seem to do this deliberately since you know better. Are you really suggesting that the mainstream view is contradictory or are you just pretending to be stupid when it suits your purposes?
    — noAxioms

    I said: “at every moment of the trip twin A sees twin B aging more slowly, yet when they reunite twin B has aged more”, are you really claiming that’s false?
    Obviously, since the reuniting moment verifies otherwise.
    There can be zero turnaround time if you invoke triplets instead of twins.
    There there is no turnaround at all. Yes, I've used tag-team examples for those who refuse to consider an acceleration case, but now you have to explain how there's Louis who is way out there and already seriously younger (in his own frame) than Huey and Dewey at their separation event at age zero. It appears they're not triplets after all.

    From the point of view of the traveling twin
    That point of view is not inertial, which is making the same obfuscating mistake as Mike in the OP. It makes it look like distant people age quickly or possibly backwards which they simply don't. An accelerating person does not define an inertial reference frame. Do it from any inertial reference frame and the ages work out.

    One can do it the complicated way (the non-inertial frame in which the traveler is stationary the whole way), but then the twin back home ages mostly during the time taken to turn around. If it's instant, then the remote age change is instant. Either way, your assertion above that 'at every moment of the trip twin A sees twin B aging more slowly' is wrong. It happens during the acceleration, however long that takes.

    you can even simulate an instantaneous turnaround using a second spaceship.
    Can't jump to the other ship without accelerating. The ship has nothing to do with it. Maybe the traveler takes Earth with him and leaves the other twin in a ship without fuel back home.

    Yet when they reunite the clock of the staying twin has ticked more. Sure you can explain that by invoking different frames, the point is it’s extremely confusing.
    You're making it confusing by using a non-inertial object as your reference. So don't do that if reducing confusion or reducing complication is your goal.

    If you mean the inertial frame in which the CMBR is isotropic here, that is not a valid candidate for the preferred frame of the universe since no inertial frame foliates all of spacetime. In other words, galaxies like GN-z11 (something we can see) does not even exist in that inertial frame since it is moving at well over light speed and thus hasn't yet been born.
    — noAxioms

    The Hubble law doesn’t apply to arbitrarily large distances.
    Oh doesn't it now. Are we in a privileged location in space where it seems to work out to a fixed distance from us in every direction, but if we were near the edge of that, it would only work if we looked back at Earth and not further away from Earth?
    If not, what do you mean by this? The comoving coordinate system (that based on the postulated absolute frame) has the Hubble law continuing forever.

    If you assume it does then you get superluminal velocities.
    No you don't. Velocity is a property under absolutism, not a relation. All those galaxies are nearly stationary. The separation between us and them is growing at a rate more than c, but velocity is not defined as a relative change in position relative to a reference in that view. That's the SR view, and the universe is not described by SR over large distances. That's a good part of why the absolute frame cannot be inertial.

    Just like if you assume that the speed of a car increases by 10m/s every second eventually that car will exceed the speed of light, that doesn’t mean it ever gets there.
    First of all, under SR, this isn't true. The problem is that it takes infinite energy to accelerate the last bit, so it cannot be sustained. What can be done is indefinite proper acceleration of 1G like that, in which case light speed is never reached.

    Under absolute view, the car slows down over time by itself, and at high enough speeds, the slowing balances the proper acceleration and the two cancel out. I'm not making fun of the view. It actually works this way.
    I actually tried to draw a picture of the whole universe using an inertial frame, including these 'superluminal' objects. Under SR, speeds do indeed add up using the relative rule and light speed can never be reached. The picture works fine until I attempted to work acceleration of expansion into it, and I could not do it without violating fixed light speed in the coordinate system. I don't think I can post pictures here or I'd show it to you, but it is a picture of non-absolute physics.

    You can very well pick a global frame in which nothing is superluminal.
    That you can, and they have diagrams of it. All the super-large-scale pictures use it, which prompted me to attempt it using inertial rules since I could find nobody else attempting it on the web.

    See that’s the kind of confusing stuff with the mainstream view, on the one hand they say nothing exceeds the speed of light, on the other hand they extrapolate Hubble’s law to arbitrarily large distances
    Hubbles law is about the increase of proper distance measured over curved lines of comoving time, not about absolute speed, which is assumed to be fixed at zero. Our galaxy for instance moves at I think under 0.002c, but our solar system is well under that figure. The other galaxies move at similar speeds, nowhere near light speed. That's the consequence of a non-inertial preferred frame.

    No. I put a clock in there and it still paces the one on the outside. That's empirical evidence against the dilation explanation of the apple rotting.
    — noAxioms
    Or the apple is time dilated in the fridge but not the clock.
    Time that picks and chooses. Yea sure.

    Also have we ever tested if a mechanical clock gets time dilated at high velocities?
    To my knowledge only atomic clocks have been tested.
    Muons make great clocks. Accurate to at least 2 digits and easy to accelerate.

    Sure they’re more accurate, but then maybe their time dilation has to do with their internal processes, there is no evidence that everything gets time dilated due to velocity.
    Let me know how that works out for you.

    The geometry method for instance explains (and is not just a mathematical convenience) why the height of a flag pole can be taller or shorter depending on your choice of the orientation of the 'up' dimension. That is physical length contraction without any change to the proper dimensions of the pole.
    — noAxioms

    Well a flag pole can certainly appear differently depending on how you look at it, that doesn’t imply that the flag pole physically changes when you do that
    Exactly. Ditto with length contraction. The change is only a mathematical coordinate difference, not a physical change. I think it is actually a physical change in the absolute interpretation. Fast things really do physically change in that view.
  • tim wood
    8.7k
    ↪tim wood
    But you say time is unreal, that time is completely incoherent. You'll have to own that yourself. Make your case. After all, your opponent is only a wristwatch.
    — tim wood

    I also didn't say that. So again, well done for paying no attention whatsoever. I think time is real.
    Bartricks
    Er, you realize that concept of time is completely incoherent?Bartricks

    On the "time is unreal," my bad, you're correct, I didn't see it in your post. Here it is: "McTaggart is most famous for arguing that time is unreal." From https://plato.stanford.edu/entries/mctaggart/#UnrTim section 3, first line. Maybe you should do some reading.

    What are we to do with a blowhard like you, Bartricks. Btw, do you own a watch or a clock of any kind? Do you ever make appointments, and how do you know when they are? Ever take a trip on an airplane? Even a train? Or do you just ask people what time it is?
  • Bartricks
    6k
    erm, is you understanding English be? Are you fluent being?

    McTaggart - whom you've never read - argued that time is unreal. That doesn't mean I think time is unreal. Mentioning someone doesn't mean you endorse their views. Do you not realize that?

    McTaggart - the person whose work you've never read, but is the first person you read when you do philosophy of time - argued time is unreal. I don't. He does. I don't. I'm not him, see? He's not me, and I'm not him.

    I think time is real. Real. R.e.a.l. Really really realingtons.

    Now, when I said "that concept of time is incoherent' I was referring to the idea of time being relative. That is, the idea I'd mentioned in the previous sentence. That - you know, the one just mentioned - is incoherent.

    That doesn't mean the same as 'the concept of time is incoherent'.

    Btw, do you own a watch or a clock of any kind? Do you ever make appointments, and how do you know when they are? Ever take a trip on an airplane? Even a train? Or do you just ask people what time it is?tim wood

    Do you have a cerebrum?

    I note too that you still - still - haven't answered any of my questions.

    I told you what relativity involves. I asked you to explain to me how the twin paradox (and it really isn't a paradox) implies that time is relative. I asked you to explain to me how drawing that conclusion would be any less stupid than concluding that time passes more slowly in fridges. And I asked you if you'd read McTaggart.
  • leo
    882
    I said I'm not going to be available for a while, I shouldn't be here now, but I guess the urge to respond is too strong, so I'll be quick:

    I suppose that explains the hunt for the ether, even though I don't think it is posited to be detectable.noAxioms

    There really is a medium permeating all space that is detectable, the vacuum isn't nothingness it is full of electromagnetic radiation and so-called virtual particles. Now consider an atomic clock at rest in that medium (isotropic radiation coming from all around) and an atomic clock in motion (anisotropic radiation). An atomic clock is based on the behavior of atoms (and electrons), that behavior depends on their environment, why should we expect that the two atomic clocks behave the same when one receives isotropic electromagnetic radiation and the other one anisotropic electromagnetic radiation? That's the kind of thing I refer to when I talk about a constructive theory, there's something there to understand and describe, we have to take into account both the atomic clock and its environment in order to fully describe how it works. And maybe we'll realize that an atomic clock runs slower when it receives anisotropic radiation than when it receives isotropic radiation. See what I mean? There would be no need for relativity there.

    Keep in mind I'm just asking here since I'm not totally familiar. If the ether moves/flows, where does the ether go when it gets to say the center of say Earth?noAxioms
    No, the question above talks about being in a dense hollow shell, a region of a flat gravitational field (no acceleration, but still in a well). Let's assume the ball is stationary so the dilation is completely due to gravity and not the ball moving through the ether or being in an acceleration field.noAxioms

    I don't know, the ether flow model works well in many cases but it seems to be problematic in the kind of situation you mention. I haven't looked too hard into it. What I described in the above paragraph seems much more promising to me.

    I suppose Lorentz's theory has been generalized then? I wonder how black holes are handled since they don't seem to exist under LET.noAxioms

    I gave a link to an example of such a generalization, but it could be generalized in other ways.

    No, but it is sort of one of my points. All clocks anywhere are dilated, no matter their position or velocity. They never compute how dilated these clocks are. Nothing exact is asked for. A single digit of precision would be nice. You'd think the 'time flows' proponents would want to know the objective rate of time flow, but they seem to avoid it like it's something embarrassing.noAxioms

    As I said I don't consider that time 'flows', but in order to compute absolute time dilation one would have to have detected the absolute frame in the first place, so until then that absolute dilation is unknown, but even without knowing it we can make accurate predictions, again that doesn't prove there is no absolute frame or no absolute dilation.

    If the twins are approaching each other, they see the other aging faster. Yes, that's doppler, so 'sees' is a misleading choice of verbs. What each actually does is compute the age of the other, and in order to do that, each needs to select a frame, and if they select different frames (there is no reason they need to), then they're going to get different answers of course.noAxioms

    Yes strictly speaking they don't 'see', I explained that in another post, what they see is mostly Doppler not the real rate of the other clock. But when each of them assumes that light travels at c in all directions in their frame, each of them infers (computes) that in their frame the other clock is ticking more slowly.

    One can do it the complicated way (the non-inertial frame in which the traveler is stationary the whole way), but then the twin back home ages mostly during the time taken to turn around. If it's instant, then the remote age change is instant. Either way, your assertion above that 'at every moment of the trip twin A sees twin B aging more slowly' is wrong. It happens during the acceleration, however long that takes.noAxioms
    Can't jump to the other ship without accelerating.noAxioms

    And that's exactly the kind of stuff that confuses people. The idea of an instant "remote age change". If there is no acceleration, there is no "during the acceleration".

    Consider that we don't even need to talk about twins, we can simply talk about the clock readings. In that way there is no need to jump to another ship and accelerate, whatever reading the clock of the first spaceship indicates can be transmitted to the other spaceship going the other way when they pass by one another, and the clock of the second spaceship can be synchronized to it. In that way it is as if the clock had been transferred to the second ship without any acceleration at any point. Sure there is a change of inertial frame. But still, at any moment, it is as if from the point of view of the moving clock, the staying clock is always ticking more slowly.

    Of course if we don't take into account the change of inertial frame we don't get a correct result. But consider that people don't understand why the staying clock would have ticked more if at every moment from the point of view of the moving clock it ticked more slowly! And that's the difference with the absolute frame explanation of the ether theory, in it the staying clock ticks more quickly on at least one half of the trip no matter what the true absolute frame is, and that people can understand, because it doesn't defy common sense, it doesn't leave people confused.

    Oh doesn't it now. Are we in a priveleged location in space where it seems to work out to a fixed distance from us in every direction, but if we were near the edge of that, it would only work if we looked back at Earth and not further away from Earth?
    If not, what do you mean by this?
    noAxioms

    We may be in a privileged location (how would we know we aren't), but let's assume we aren't anyway, and that the Hubble law applies from the point of view of other galaxies, that redshift of distant galaxies is proportional to their distance. Even if that redshift/distance law applies to arbitrarily large distances, the velocity/distance law doesn't, or at the very least there is no reason it should apply.

    If we assume no superluminal velocity, then arbitrarily large redshift doesn't translate to arbitrarily large velocity, as the redshift increases the velocity approaches the speed of light, just like in a given inertial frame if you have a projectile with a very high redshift its velocity is close to the speed of light not above.

    The thing most people don't seem to realize (even cosmologists) is that we don't need to invoke a physical expansion of space between galaxies to account for Hubble's law (like with the balloon analogy). If you have an absolute inertial frame, you can see all galaxies moving like projectiles. If these projectiles are all moving away from one another because of a huge explosion a long time ago you end up with the Hubble law, with the matter that was the furthest away from the center of the explosion moving faster as it was pushed by the matter closer to the center. Again we can explain it all in that way, there is no need to complicate matters by invoking superluminal velocities and space expansion and local inertial frames and whatnot.

    Even if galaxies are accelerating away from one another (they might be, or maybe the evidence/reasoning for dark energy is flawed), that still doesn't imply superluminal velocities nor the absence of an absolute inertial frame.

    All those galaxies are nearly stationary. The separation between us and them is growing at a rate more than c, but velocity is not defined as a relative change in position relative to a reference in that view. That's the SR view, and the universe is not described by SR over large distances. That's a good part of why the absolute frame cannot be inertial.noAxioms

    I answered that right above. The galaxies don't have to be seen as stationary. The separation between us and them doesn't have to be seen as growing at a rate more than c. The absolute frame can be inertial. See the problem with the mainstream narrative? Pushing beliefs as if they were truths.

    First of all, under SR, this isn't true. The problem is that it takes infinite energy to accelerate the last bit, so it cannot be sustained. What can be done is indefinite proper acceleration of 1G like that, in which case light speed is never reached.noAxioms

    I know that isn't true, yet that's exactly what they do when they say that the recession velocities of galaxies are proportional to their distance no matter how distant they are. They don't take into account how velocity approaches the speed of light as redshift increases. They do exactly the same as saying that the car would accelerate beyond the speed of light if accelerated for long enough.

    I actually tried to draw a picture of the whole universe using an inertial frame, including these 'superluminal' objects. Under SR, speeds do indeed add up using the relative rule and light speed can never be reached. The picture works fine until I attempted to work acceleration of expansion into it, and I could not do it without violating fixed light speed in the coordinate system. I don't think I can post pictures here or I'd show it to you, but it is a picture of non-absolute physics.noAxioms

    I did that too, indeed the speeds add up without reaching the speed of light, and the Hubble law becomes something like v = c*tanh(f(D)) or something like that I don't recall exactly, the recession velocity is no more proportional to distance, there is no reason that it should be proportional to distance, that's a pure belief based on nothing while being pushed as truth.

    If you include acceleration there is no reason you should break the speed of light, just like the car doesn't break the speed of light, there must have been an error in your derivation.

    Muons make great clocks. Accurate to at least 2 digits and easy to accelerate.noAxioms

    Muons aren't mechanical clocks.

    Time that picks and chooses. Yea sure.noAxioms
    Let me know how that works out for you.noAxioms

    That sounds stupid only because you assume special relativity is true, and yet if that's the case special relativity would be shown to be false. Consider the first paragraph I wrote in this post. There is no reason that anisotropic radiation coming from all around would affect an atomic clock and an apple in the same way, their internal processes aren't the same.
  • Metaphysician Undercover
    12.3k
    Keep in mind I'm just asking here since I'm not totally familiar. If the ether moves/flows, where does the ether go when it gets to say the center of say Earth?noAxioms

    Physical objects must be conceived of as part of the ether, properties of the ether, juust like particles are conceived of as property of the fields described by wavefunctions. Michelson-Morley experiments demonstrate that the ether is not a substance independent from the substance of material objects. Modeling the ether in this way connects all objects as property of one ether. Now the relations between distinct material objects are simply a feature of that ether. Observations like "spatial expansion", indicate changes in the ether itself, which affect the relations between objects. as motions which are inconsistent with a static ether.

    As I said I don't consider that time 'flows', but in order to compute absolute time dilation one would have to have detected the absolute frame in the first place, so until then that absolute dilation is unknown, but even without knowing it we can make accurate predictions, again that doesn't prove there is no absolute frame or no absolute dilation.leo

    With the ether theory, the flow of time can be represented as the flow of ether. It might not be proper to call it a flow though, rather it is an activity, as evidenced by spatial expansion and other related concepts, and that activity is what we call the flow of time.

    If you have an absolute inertial frame, you can see all galaxies moving like projectiles.leo

    The "absolute inertial frame" cannot be produced without a proper representation of the ether flow, which may not be a flow at all, but some other unknown type of activity. So with our present knowledge of these things it only makes sense to talk about an "absolute inertial frame", as something desired but completely unobtainable. To claim as you do, that we might just produce an absolute inertial frame from our present understanding is not realistic, because there are too many unknown factors like dark matter and dark energy.
  • leo
    882
    To claim as you do, that we might just produce an absolute inertial frame from our present understanding is not realistic, because there are too many unknown factors like dark matter and dark energy.Metaphysician Undercover

    Dark matter and energy aren't incompatible with an absolute inertial frame. Also it may be possible to come up with a theory that doesn't need to invoke dark matter and energy to explain observations, since the only evidence that we have for them comes from the fact that observations do not match the predictions of general relativity, which is extremely weak evidence really. Every theory has a domain of validity, that general relativity is accurate to account for some phenomena at some scales doesn't imply that it is accurate at all scales...
  • ernestm
    1k
    I think I've been very clear. I want to know how the twin case is supposed to provide us with evidence that time is relative.
    — Bartricks
    What in the world does "time is relative" mean? Or more accurately, what in the world do you think it means?
    tim wood

    Actually Einstein has a very philosophical answer for this. When a child asked him to explain his theory of relativity, he replied "you know when you are in a class and watching the clock, and the five minutes to break last forever? But then the break is 30 minutes and you think it's over in a jiffy? That means you understand my theory, which only says, time is only meaningful in the perception of the observer, who is now you, so now, what time is it? It is time for you to go and play :) "
  • Metaphysician Undercover
    12.3k
    Dark matter and energy aren't incompatible with an absolute inertial frame.leo

    That's right, but until it's understood what they are, a proper absolute inertial frame cannot be produced. And understanding what they are requires a proper understanding of the nature of space, and this is most likely as an ether. So the way to an absolute inertial frame is through ether theory.
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Get involved in philosophical discussions about knowledge, truth, language, consciousness, science, politics, religion, logic and mathematics, art, history, and lots more. No ads, no clutter, and very little agreement — just fascinating conversations.