• noAxioms
    1.5k
    I think what I am really getting at is: is a purely Newtonian universe possible, with all relativity being Galilean Relativity. Could God create such an universe which neither violated Newtonian physics nor Relativity as an illusion due to the limits of the speed of light, meaning limiting the speed of information transfer?FreeEmotion
    God is defined to be able to do anything, yes. But no, this is not that universe. Such a universe is possible. It would probably have luminiferous aether if there was a light speed of sorts, but the aether would be something you could carry with you to increase the speed of information transfer. There would be no limit to that. If there was a limit, then no Galilean Relativity.

    Sound works like that. It has a speed limit (that varies with the medium), but if I'm in a supersonic jet, I can hear the person behind me talking. Outside, nobody hears the jet approaching. Sound obeys Galilean Relativity only because we can carry its aether with us.

    One can imagine that information transfer is limited by the speed of light, reality is not. For example, is God's knowledge of an event is delayed by the time it takes light from the event to reach Him? Surely this is an absurd statement? (Asimov hinted at this, that the speed of light was slowing the second coming of Christ).
    Your God has a location, and light travels there? Indeed, that's absurd. God is outside and does not gain knowledge the way we do: by waiting for physical photons and such to reach us. God has access to all states, and thus can meaningfully be said to be everywhere.
  • noAxioms
    1.5k
    Not a religious argument but more an experientialRich
    Are you claiming there would be an experiential difference between the views? That would constitute an empirical test, no?
    and intuitive one based upon Bergson's studies of biology, mathematics, and education.
    Intuitive yes, but if we went by that, the world would still be flat with the sun being carried overhead each day. Very few scientific advancements in the last couple centuries would qualify as intuitive findings.

    Time (durée), as it is experienced, is heterogeneous and continuous.
    ???? So we should experience a series of stationary images while watching a 60fps movie.
    This is the opposite of scientific time which is homogenous and discontinuous.
    No idea how this relates to ontology of time, or what you mean by 'scientific time'.
  • Rich
    3.2k
    Are you claiming there would be an experiential difference between the views?noAxioms

    Indeed, explicit within Relativity, two observers are experiencing events differently. To Bergson, time (duree), is precisely what we experience as life. Memory is continuously evolving and sometimes it feels as time is moving very slowly and sometimes very quickly depending upon what we are experiencing. This is the duree of life, what Bergson called real time. Thomas Mann (and other modernist writers) attempted to express this experience in their novels, such as Mann's Magic Mountain.

    What Bergson, in his critique, attempted to express was that life as experienced is different than life as science views it, science addressing the issue of determining simultaneity of events.

    Intuitive yes, but if we went by that, the world would still be flat with the sun being carried overhead each day. Very few scientific advancements in the last couple centuries would qualify as intuitive findings.noAxioms

    Our way of looking at things change as we share actual experiences, and in almost all cases, some creative intuition is involved whether it be ocean travel around the Earth or in a laboratory. It is in the laboratory, where creative experiments are first designed and implemented, that new discoveries are found. I would like to emphasize that it is the creative mind of the applied scientist in the laboratory that encourages evolutionary change. Theorists most frequently react to surprising new developments (Kuhn) that disrupt. Bohm writes quite eloquently about the nature of creative intuition in the advancement of scientific understanding.

    On another front, Daoists, Greeks, and Muslims, developed a very concrete and effective view of health and medicine based upon experience and intuition. Creative intuition is the heart of evolution, not natural selection
  • FreeEmotion
    773
    Your God has a location, and light travels there? Indeed, that's absurd. God is outside and does not gain knowledge the way we do: by waiting for physical photons and such to reach us. God has access to all states, and thus can meaningfully be said to be everywhere.noAxioms

    So does this mean that the Relativity of Simultaneity does not apply to God? I would think he knows the Universe the way we would know fish in a fishbowl - we know were each one is, the limits, the center of the fishbowl ( I note your comments) , and the position and velocity of each fish in real time (since fish move at very much less than the speed of light, there are no detectable relativistic effects for us). He would know whether a fish is absolutely at rest or at motion with regard to the edges of the fishbowl, for example, or the water (ether?) or an arbitrarily chosen set of water molecules which happen to be in the same inertial frame?

    Does Relativity apply to God?
  • FreeEmotion
    773
    Sound works like that. It has a speed limit (that varies with the medium), but if I'm in a supersonic jet, I can hear the person behind me talking. Outside, nobody hears the jet approaching. Sound obeys Galilean Relativity only because we can carry its aether with us.noAxioms

    Does Special Relativity apply only to 'real time' events? That is, events where information is communicated only by the speed of light and at the speed of light? No examining of historical traces or event logs, Einstein's train thought experiment seems to only illustrate real time effects.
  • FreeEmotion
    773
    This forum is a much freer and more open forum than some of the science fora I have been on. Refreshing change. Thank you.
  • noAxioms
    1.5k
    So does this mean that the Relativity of Simultaneity does not apply to God?FreeEmotion
    I think (without proof) that time is part of the universe, and that clocks measure it (temporal distance). God is outside the universe presumably (unless he created himself sort of like the legend of Abe Lincoln being born in a log cabin he built with his own hands) so the physics of this universe have zero application to God. If you want, you can suggest the physics of God as almost everybody does, but somehow I don't think God takes much notice of us telling him how his physics must work.
    Now if you put time outside the universe (as Rich does), then it can be said that God existed before the universe and eventually caused it to begin, and it is a thing that continues to 'happen'. Then I guess the question of relativity at least has some bearing. Anyway, in this interpretation, time is not part of the universe and thus would seem utterly undetectable. Clocks don't measure it (as relativity shows), but people are special and apparently do detect it, but not well enough to say what is going on elsewhere right now, so I find this claim completely dubious. This is probably not a fair description, since it is a view I don't hold. Ask the question of its adherents.

    I would think he knows the Universe the way we would know fish in a fishbowl - we know were each one is, the limits, the center of the fishbowl ( I note your comments) , and the position and velocity of each fish in real time (since fish move at very much less than the speed of light, there are no detectable relativistic effects for us). He would know whether a fish is absolutely at rest or at motion with regard to the edges of the fishbowl, for example, or the water (ether?) or an arbitrarily chosen set of water molecules which happen to be in the same inertial frame?
    Relativity says there is no outside boundary, the bowl grows over time, and there is no possible designation of something stationary that gives a sub-light velocity to most of the fish.
    The center has no position and no duration, so it does not define such a reference. It is an event, not a frame. Where on this map is the center of Earth? "Not on the map." OK, but which spot is directly over the center? "All of them".
  • noAxioms
    1.5k
    Does Special Relativity apply only to 'real time' events? That is, events where information is communicated only by the speed of light and at the speed of light? No examining of historical traces or event logs, Einstein's train thought experiment seems to only illustrate real time effects.FreeEmotion
    Not sure what a 'real time event' is. If there is communication, there is the event of the message being sent, and another where it is received. That's two events.
    Einstein's experiments involve implications of frame-independent constant light-speed, so yes, there's going to be discussion of light in them. Not sure how that makes it more 'real time'.

    This forum is a much freer and more open forum than some of the science fora I have been on. Refreshing change. Thank you.FreeEmotion
    Been on that, and yes, it seems a place for people who know their stuff to make fun of people who don't. Some are worse that way than others.
  • noAxioms
    1.5k
    Are you claiming there would be an experiential difference between the views?
    — noAxioms

    Indeed, explicit within Relativity, two observers are experiencing events differently. To Bergson, time (duree), is precisely what we experience as life. Memory is continuously evolving and sometimes it feels as time is moving very slowly and sometimes very quickly depending upon what we are experiencing. This is the duree of life, what Bergson called real time. Thomas Mann (and other modernist writers) attempted to express this experience in their novels, such as Mann's Magic Mountain.
    Rich
    So your claim is that under Minkowski time (time has same ontology as space, something that relativity suggests but doesn't demand), experienced time would not seem to drag when one is bored?
    Not sure where in any of the descriptions that prediction is made.
  • Rich
    3.2k
    Intuitive yes, but if we went by that, the world would still be flatnoAxioms
    Yes, Minkowski time, which is gridlike, is a convenience for scientific problems. It is not real time/duration as we experience it in life.
  • noAxioms
    1.5k
    Intuitive yes, but if we went by that, the world would still be flat
    — noAxioms
    Yes, Minkowski time, which is gridlike, is a convenience for scientific problems. It is not real time/duration as we experience it in life.
    Rich
    Interesting choice of quotes to attach to that response.
    So you're saying that the round Earth model is just a convenience for scientific problems, not corresponding the real flat world as we experience it in life.
    Not absurd, but pretty idealist. Not sure if FreeEmotion is asking about this.
  • Rich
    3.2k
    Interesting choice of quotes to attach to that response.
    So you're saying that the round Earth model is just a convenience for scientific problems, not corresponding the real flat world as we experience it in life.
    Not absurd, but pretty idealist. Not sure if FreeEmotion is asking about this.
    noAxioms

    Not what I said or meant.
  • FreeEmotion
    773


    Could we define an arbitrary boundary based on a set of stars that move very slowly relative to each other? Within this frame of reference, we can define absolute motion, does this make sense? How large does the frame of reference have to be to become useful?
  • FreeEmotion
    773
    Not sure what a 'real time event' is. If there is communication, there is the event of the message being sent, and another where it is received. That's two eventsnoAxioms

    Take for example the train and lightning strikes thought experiment. I have always thought that one could tell which lightning strike occurred first by stopping the train, and taking readings with measuring rods and clocks.

    At the time the train is moving, however, it may not be possible to do this, due to the impossibility of using variations in light speed to determine simultaneity of events. This is an 'as it happens' view. Science also consists of taking measurements of past events using not speeds but displacements and locally recorded times.
  • noAxioms
    1.5k
    Could we define an arbitrary boundary based on a set of stars that move very slowly relative to each other? Within this frame of reference, we can define absolute motion, does this make sense?FreeEmotion
    If it is relative to something (your set of stars), it is not absolute. Any absolute frame would not be in reference to a particular thing.

    How large does the frame of reference have to be to become useful?
    Frames don't have a size.
  • noAxioms
    1.5k
    Take for example the train and lightning strikes thought experiment. I have always thought that one could tell which lightning strike occurred first by stopping the train, and taking readings with measuring rods and clocks.FreeEmotion
    In the frame of the train, it is already stopped. Typically, the lightning example has the two lightning events being simultaneous in the frame of the platform, but the experiment works with the roles reversed as well.

    At the time the train is moving,
    Only in the frame of the platform
    however, it may not be possible to do this, due to the impossibility of using variations in light speed to determine simultaneity of events.
    The experiment presumes a fixed light speed, as has always been measured. If the speed was variable, empirical measurements would vary depending on the frame in which the experiment took place. This has been done, and it is always a constant.

    This is an 'as it happens' view. Science also consists of taking measurements of past events using not speeds but displacements and locally recorded times.
    In the train example, there are two observers taking the measurements, each spatially centered between the two events. So the events are simultaneous if they're detected at the same time, even though it takes time for the light from the events to reach the measurer.
  • FreeEmotion
    773


    The Lumiferous Ether when it was thought to exist, was to serve the purpose of an universal frame of reference. A local volume of the Ether would then serve the same purpose.
  • noAxioms
    1.5k
    The Lumiferous Ether when it was thought to exist, was to serve the purpose of an universal frame of reference. A local volume of the Ether would then serve the same purpose.FreeEmotion
    Yes, that was the model for a while. It predicts that if two observers were in the same local volume but only one of them stationary, the moving one could be detected by that observer measuring a different speed of light. But it is always measured the same, falsifying this view.
  • FreeEmotion
    773
    If it is relative to something (your set of stars), it is not absolute. Any absolute frame would not be in reference to a particular thing.noAxioms

    I don't understand, can the same be said of the Ether? The Ether being the particular thing?
  • noAxioms
    1.5k
    I guess if you define Ether to be a substance that can be said to be stationary, then it defines a frame, and you can move relative to it, and light speed would be non-constant. This is pretty much how they falsified the ether model.
  • FreeEmotion
    773
    Yes, that was the model for a while. It predicts that if two observers were in the same local volume but only one of them stationary, the moving one could be detected by that observer measuring a different speed of light. But it is always measured the same, falsifying this view.noAxioms

    So there is no philosophical objection to light, or light waves or photons or whatever, being measured at the same speed no matter how fast the emitter and receiver are moving relative to each other?

    None?

    Can the concept of an object whose speed always is your speed + its natural speed raise any alarm bells?
  • noAxioms
    1.5k
    So there is no philosophical objection to light, or light waves or photons or whatever, being measured at the same speed no matter how fast the emitter and receiver are moving relative to each other?

    None?
    FreeEmotion
    None, yes. Emission and detection of a photon are two events and events do not have velocities and do not define frames. The relative velocity of the apparatus involved is thus completely irrelevant.

    Can the concept of an object whose speed always is your speed + its natural speed raise any alarm bells?
    That's the intuition, and intuition is wrong here. All measurements (light in a vacuum) always yield the same number. Light is slowed if it goes through water, glass, etc.
  • FreeEmotion
    773
    Let's take the first instance. You have a two detectors, that measure when light passes one and then when light passes the other, D1 and D2. You then have light emitted from an emitter of course, from somewhere outside the detector, along the same axis as D1 and D2.

    E >>>>>>>>>>>>>>>>>D1>>>>>>>D2>>>>>>>

    It makes no difference if the emitter is moving towards or away from the detecting apparatus, the speed of light they measure will always be the same. Is that correct?

    One explanation is that E, D1 and D2 all are immersed in an invisible medium just like air is to sound, that transmits light by first responding to the disturbance at E and then transmitting the light at the natural speed that the ether transmits light to D1 and D2.

    I suppose no alarm bells need to be raised here, this is the explanation involving ether.

    What I think I meant was, in the absence of ether, what other explanation is possible? The ballistic theory will be ruled out by the independence of the speed of the emitter.

    The wave theory would work, but it needs a medium.

    How would you describe the way in which light is transmitted, without using either the ether, waves in ether or the ballistic theory? What is this concept and can it be put into words?
  • noAxioms
    1.5k
    Let's take the first instance. You have a two detectors, that measure when light passes one and then when light passes the other, D1 and D2. You then have light emitted from an emitter of course, from somewhere outside the detector, along the same axis as D1 and D2.

    E >>>>>>>>>>>>>>>>>D1>>>>>>>D2>>>>>>>

    It makes no difference if the emitter is moving towards or away from the detecting apparatus, the speed of light they measure will always be the same. Is that correct?
    FreeEmotion
    You're describing objects, not events. The above setup needs a defined frame to take a measurement, and none has been specified. So for instance, the D1 detector doesn't know when the light was emitted and thus how long it took to get there or how far it traveled. That needs definition, so the measurement of elapsed time can be taken. You've not provided that.
    That said, if the experiment is expressed as three events instead of three potentially moving objects which are not events, then the measurement can be taken in any frame and it will always result in the same speed of light.

    One explanation is that E, D1 and D2 all are immersed in an invisible medium just like air is to sound, that transmits light by first responding to the disturbance at E and then transmitting the light at the natural speed that the ether transmits light to D1 and D2.

    I suppose no alarm bells need to be raised here, this is the explanation involving ether.
    This explanation has been falsified long ago. You persist in a model that predicts different results than those that are empirically observed.

    What I think I meant was, in the absence of ether, what other explanation is possible? The ballistic theory will be ruled out by the independence of the speed of the emitter.

    The wave theory would work, but it needs a medium.

    How would you describe the way in which light is transmitted, without using either the ether, waves in ether or the ballistic theory? What is this concept and can it be put into words?
    Relativity is not a statement about the mechanism of light getting from here to there. It is about the geometric implications that directly follow from a fixed light speed.
  • FreeEmotion
    773
    I am simply looking at the previous explanations as well.

    Relativity is not a statement about the mechanism of light getting from here to there. It is about the geometric implications that directly follow from a fixed light speed. — noAxioms

    This does clarify things somewhat, however questions remain:

    What is the underlying method of light transmission that relativity ultimately describes? With Newton, you had a mechanism - photons, if relativity is a description of reality, then what is the underlying reality?
  • FreeEmotion
    773
    You're describing objects, not events. The above setup needs a defined frame to take a measurement, and none has been specified. So for instance, the D1 detector doesn't know when the light was emitted and thus how long it took to get there or how far it traveled. That needs definition, so the measurement of elapsed time can be taken. You've not provided thatnoAxioms

    OK, but the distance and time to D1 is not needed, just take the event consisting of light reaching D1 and the event of light reaching event D2, and measure the speed in between.
  • Metaphysician Undercover
    13.3k
    What is the underlying method of light transmission that relativity ultimately describes? With Newton, you had a mechanism - photons, if relativity is a description of reality, then what is the underlying reality?FreeEmotion

    It is called the photoelectric effect. But it's not well understood, and that's why there is quantum uncertainty, the creation of conceptual fields, and wave functions. The inadequacy of which demonstrates that there is no underlying reality for this conceptual structure.
  • noAxioms
    1.5k
    What is the underlying method of light transmission that relativity ultimately describes? With Newton, you had a mechanism - photons, if relativity is a description of reality, then what is the underlying reality?FreeEmotion
    Relativity is not a full description of reality. A full description would need to include relativity. Light is still photons, and relativity is based on the observed fact that the speed of photons is a constant in a vacuum. It says that they have zero rest mass and frame-dependent nonzero energy. Relativity says little more than that at the level we're discussing here. Look to quantum mechanics for a better description of what a photon actually is.

    It is called the photoelectric effect.Metaphysician Undercover
    The photoelectric effect concerns emission of electrons when light shines on a surface and has nothing to do with light transmission mechanism or relativity.

    OK, but the distance and time to D1 is not needed, just take the event consisting of light reaching D1 and the event of light reaching event D2, and measure the speed in between.FreeEmotion
    OK, those are events, but how do you measure speed between events? There is no frame-independent definition of that in physics. So you've not specified a frame for these two events. Essentially you need to tell me the spatial separation between events E1 and E2, and given that we know light speed, we can compute (not measure) the time it takes for light to make the trip in the frame you've specified. This is obviously not a measurement of light speed since we're assuming a constant for it in our calculation.

    Most (all??) light speed measurements are done via round trip so the emission and detection events are in the same place and the duration can be measured by a clock. That doesn't work if the events are spatially separated. Most of the thought experiments you reference in your early posts assume an already known light speed and from there find geometric implications about the ordering of events and the distance between them.
  • Metaphysician Undercover
    13.3k
    The photoelectric effect concerns emission of electrons when light shines on a surface and has nothing to do with light transmission mechanism or relativity.noAxioms

    I believe that when light is transmitted through a substance, there is an interaction between the electrons of the material, and the light energy.
  • noAxioms
    1.5k
    I believe that when light is transmitted through a substance, there is an interaction between the electrons of the material, and the light energy.Metaphysician Undercover
    I've not heard of anything like that, but I'm no expert either. All descriptions I read are from light being absorbed, not just passing by if it was merely being transmitted through a material that passes light like glass. Yes, glass interacts, but not by giving off electrons.

    What does any of this have to do with relativity thought experiments that F-E is asking about?
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