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B A question of why time dilates and what is described by it

  1. Nov 14, 2016 #1
    I know what time dialation is, that is not the question. I don't know what school level this is (the prefix thingy in the title) since I am exploring this personally and never had schooling on it, only knowing the tidbits I've found or heard, that don't really go in depth.

    The question is two-fold.

    First, is time truly seen as an objectively existing thing, or is it simply a measure of how much change has occured relative to how a reference amount of change for a given frame of reference?
    Second, are theories on why time dialation occurs? For example, if the functioning of things, including observers and clocks, depends on how much electrons have rotated around neucli (being systems built of atoms), then it logically follows that any system made of atoms would function more slowly at faster "speeds," since the number of rotations would be fewer at faster "speeds" given the idea that the electrons stay travelling at the same rate.

    This then leads to the question, is the speed of light and possibly the theory on time (depending on answers above) a description of how the universe works as the emergent result of a mix of possibly simpler laws of nature, or is it assumed that the speed of light is an inherent law in an actual thing (rather than a merely abstract model) that limits other laws of nature?

    Last question, does this theory preclude the idea of an ether of some sort? (the only experiments I know of, were testing for an ether wind from the earth moving around the sun, but of course, there are possible reasons why such an ether wind would not exist for the earth, which would seem rather likely if an ether did exist.)
     
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  3. Nov 14, 2016 #2

    Orodruin

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    The prefix should reflect your level of knowledge in order for responders to be able to direct their replies to that level, not to the subject itself. I have changed the thread label to B.

    It is unclear what you would mean by this. Time is, by definition, what is measured by a watch. The standard frame setup in SR involves an array of synchronised watches at rest in that frame. A clock generally measures how many times a process has repeated itself, such as the number of times the big hand has moved past the vertical position.

    Time dilation is a prediction of special relativity. In order to understand it, you need to understand special relativity (and it is very well understood within special relativity). If you want a "reason", it follows directly from the postulates of SR and so it would be because the speed of light is the same in all frames.

    Electrons do not "rotate around" nuclei. This classical likeness is not applicable at such small scales.

    In general, your ideas seem to build upon misconceptions of how the theory actually works. If you want to solve your "issues", you need to focus on learning the actual theory and not on popular scientific descriptions of it.
     
  4. Nov 14, 2016 #3

    PeroK

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    To be honest, from the rest of your question it's clear that you don't know what time dilation is, so a good first step would be to read more about it. Time dilation is not "time slowing down at faster speeds".
     
  5. Nov 14, 2016 #4
    Quote 1,
    Thanks, knowing what that is for helps quite a bit.

    Quote 2,
    Okay, consider for a moment that the watches are affected by the time dialation. Therefore, the process itself of moving hands is slowing down at faster speeds, this slowing of the process affects measurements made in comparison to the watch, basically, the rulerstick changes. So making measurements objectively can be done, but only by accounting for speed.

    The question is whether this is because of the "mechanical" aspects of the process of matter change having a limited amount of change potential being shared between the process of functioning and the process of moving, or if there is some other "thing" that imposes itself on the matter that is moving that causes it change more slowly.

    Quote 3,
    Possibly another description might be, whether the the space-time continuum is an actually real thing, or simply a mathematical model that describes how things move. If the space-time continuum is simply a mathematical model, are there theories on why the universe adheres to that model, or is it simply assumed that the space-time continuum is a thing in-and-of-itself that affects or dictates how things move? If the former, what theories are there for the time dialation effect, or if the latter, by what process does the space-time continuum affect matter?

    Quote 4
    I was referencing that atoms are not static little motes of dust. They have a process of continuous change involving moving bits, whatever the exact movement might be. If that movement is repetative, then the number of repetitions would reduce in number at higher speeds due the increase in the distance traveled by the moving parts.

    I.E. if you have two clocks that move continuously, then the hands on a moving clock would travel at move at the same rate as a stationary clock, but due to moving, some of the hand's motion would translate to moving forward, reducing how quickly the hands move around the face. This makes sense as an explanation to why time dialation exists without space-time being an actual thing. This is because, if the hands moved around the face at the same rate regardless of movement of the whole clock, then the hands could travel faster than light while the clock as whole is travelling slower than light, due the addition of both forward motion and the circular motion.

    Of course, trying to get any real info on this stuff has been a majorly unproductive pain in the posterior. The faq in here was lightyears ahead of anything I've found before. Probably just my goolgle-fu sucks horribly.
     
  6. Nov 14, 2016 #5

    timmdeeg

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    Instead of rotating electrons (which makes no sense as already mentioned) you can consider atomic clocks or even your wristwatch. Perhaps an example helps. You will not notice anything weird if you are sitting in a spaceship with high speed. Your wristwatch functions just normal. According to special relativity however people one on earth will see your watch slowing down depending on the relative velocity between spaceship and earth. Vice versa you will see clocks on the earth (and not only clocks, all motion) slow down.
     
  7. Nov 14, 2016 #6
    "To be honest, from the rest of your question it's clear that you don't know what time dilation is, so a good first step would be to read more about it. Time dilation is not "time slowing down at faster speeds."

    Except, objectively that is exactly what happens. From the point of view of each frame of reference it doesn't seem like it (and examples always make comparisons betwen subjective experiences between observers rather than trying for an objective comparison, i.e. Bob experienced a year while Fred experienced three years because Bob travelled really fast), but if you want objective measurements that can be applied to any frame of reference or point of view, either directly or via some predictable adjustment, you have to account for the changes in time.

    Basically, knowing how different frames relate to each other allows you to adapt all frames to a single frame (we'll call it the prime reference frame), and thus we can make comparisons from any frame to any other frame. Doing this shows that time slows down for frames that are travelling faster, hence, why two initially syncronized clocks end up with different times after one travels really fast for a while.

    The perception of the fast travelling observer that time doesn't slow down is an illusion because the observer is affected equally as much as the things they measure and the things they measure with.
    Thus from their pov, time doesn't appear to slow down, but when speed is accounted for and things are compared in a prime reference frame, then most certainly time did slow down. As the previous responder said, paraphrased, that time is a measure of change reletive to a reference amount of change, the amount of change occuring in a fast moving frame is less than that of a slow moving frame, aka, the amount of change reletive to a single reference change (like a clock in a prime reference frame) is less for the fast frame, therefore, time was effectively slower in that frame.
     
  8. Nov 14, 2016 #7
    Okay, part of the goal is to remove the subjectivity. It is rather understood that the brain isn't going to keep functioning at full pace if all matter moving at that speed slows down, thus the observations of the observer would slow down as well, giving the illusion that time doesn't slow down.

    Really though, many paradoxes stem from treating time as something you can move forward or backwards in, but if time is nothing more than a measure of change, and that change can occur at different rates, then going backwards in time is not possible, and therefore, no paradoxes from travelling backwards in time.


    In that case, the limitation of lightspeed makes sense.
     
  9. Nov 14, 2016 #8

    PeroK

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    The root of your problem is that you are confusing "time dilation" with "differential ageing".

    Time dilation does not "happen": it is a relationship between measurements of time in different reference frames.

    Differential ageing does happen, as a result of changing reference frames (acceleration).

    Another misconception is that are in fact no such things as "fast moving" or "slow moving" frames. All inertial reference frames are equivalent.
     
  10. Nov 14, 2016 #9

    Orodruin

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    I think that this is the number one culprit of most misconceptions about relativity - and it is something that already should be known from classical mechanics! A lot could be gained if students would just remember this when studying SR.
     
  11. Nov 14, 2016 #10

    Dale

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    A good rule of thumb is what level of math you would like to read in the answers. If you don't want anything beyond algebra then you should label it B. If you are ok with a little calculus then you should label it I. If you want them to use any and all math needed then label it A.
     
  12. Nov 14, 2016 #11
    From what I read, Einstein said you could have an objective frame of reference, but that it was pointless to do so.

    In the general case of applying reletivity, I'd agree, but I'm not looking to apply it, I'm looking for why reletivity happens the way it does, and for that I need the objective frame of reference.

    To use a metaphore, one can describe the Earth's orbit using pure math describing it as an ellipses. But that math alone can't tell you why Earth moves that way. Pure math won't reveal the existance of gravity in this, instead, you need to expand your view and start looking at other aspects of Earth and other celestial bodies, namely the sun, or have some other insight to figure out gravity. In this, gravity is part of why Earth has that orbit and not some other orbit.

    Likewise, relativity is the math of the result, it tells us how to predict things, but it doesn't tell us why things happen that way, and that is what I'm wondering. Why? What is the chain of cause and effect that results in two syncronized clocks losing sync when one travels faster than the other? Math that tells us how much that sync is off by, doesn't tell us why the sync is lost.
     
  13. Nov 14, 2016 #12

    russ_watters

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    This explanation is favored by people who are uncomfortable with the idea of time dilation and are trying to hold on to the idea of absolute time. You will need to let go of the hope that certain physical processes are affected by speed and accept that it is time itself that is different to different observers. That is what time dilation is.
     
  14. Nov 14, 2016 #13
    I finally figured out quotes! :)

    Fast vs slow moving frames are used in many examples. Even in Einstein's own writing on the topic (a train and the embankment if I recall). Frames can have relative motion, and frames are discussed as moving at speeds close to the speed of light.

    Of course, a frame doesn't really exist, it is just an abstract reference to a particular set of subjective would-be observations.
     
  15. Nov 14, 2016 #14

    Nugatory

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    The math doesn't tell us why, but Einstein's analysis of clock synchronization and simultaneity does. That, and not the formulas that you've been seeing in your reading are the proper starting point.
     
  16. Nov 14, 2016 #15

    PeroK

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    There are two fundamental problems:

    1) You have not understood the basics about reference frames and motion. And hence about time dilation.

    2) You think you have and that we are all wrong.

    That doesn't leave us in a very good possible to help you understand SR, does it? In your view, you're now having to help us understand reference frames and time dilation!
     
  17. Nov 14, 2016 #16
    But what about the other half of the hand's journey around the clock face? There some of the hand's motion would translate to moving backwards!

    You're asking a lot of questions about time dilation because you've spent some time trying to learn about it. But I think that a lot of questions would best be answered by revisiting the fundamentals of time dilation.

    Could you say that Fred experienced a year while Bob experienced three years because Fred traveled really fast?

    Let's start with the simplest scenario in which neither Bob nor Fred changes speed or direction.

    Fred and Bob are moving really fast relative to each other. Either one could be regarded as being at rest, and the other in motion. There is no experiment you can do to distinguish between being at rest and being in uniform motion, so either viewpoint is justified.

    Let's say Bob experiences one year of proper time. Proper time is the time that elapses between two events that occur in the same place. Since Fred is in motion relative to Bob, Fred will not be present at both events, so he can't experience both events. He could use two clocks to measure the time that elapses between those two events, one at Bob's location when the first event happens and one at Bob's location when the second event happens. He will of course need to make sure those two clocks are synchronized, and he will then conclude that 3 hours elapsed between the events.

    Likewise we can say that for a different pair of events Fred experiences one year of proper time. Since proper time is the time that elapses between two events that occur in the same place, and Bob is in motion relative to Fred, Bob will not be present at both events, so he can't experience both events. He could use two clocks to measure the time that elapses between those two events, one at Fred's location when the first event happens and one at Fred's location when the second event happens. He will of course need to make sure those two clocks are synchronized, and he will then conclude that 3 hours elapsed between the events.

    The apparent paradox is resolved when we realize that each will not agree that the other synchronized his clock's correctly. In addition to time dilation there is also relative simultaneity, meaning that clocks that are synchronized in a frame are not synchronized for an observer in motion relative to that frame.
     
  18. Nov 14, 2016 #17
    I finally figured out quotes! :)

    Fast vs slow moving frames are used in many examples. Even in Einstein's own writing on the topic (a train and the embankment if I recall). Frames can have relative motion, and frames are discussed as moving at speeds close to the speed of light.

    Of course, a frame doesn't really exist, it is just an abstract reference to a particular set of subjective would-be observations


    Except that presents a problem, if time is simply an amount of change relative to a reference amount of change, than naturally, there is an objective view to how much an object is changing.

    The problem comes in at trying to bring the reference with the observer without accounting for how the reference will affected.

    For example, if you take a clock and designate it as your reference and compare all change to that specific clock, you see how objects can have different rates of change, and further, that difference applies to observer's that are moving around, thus observers never perceive this difference in the rate of change because their perceptions, experiences, and thoughts are all affected equally, but in comparison to that designated reference clock, moving at different speeds affects rate of change.
    Therefore, there is some process that results in this effect.
     
  19. Nov 14, 2016 #18

    jbriggs444

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    [... snip much that ignores the problem of comparing clocks at a distance ...]
    How will you compare a clock over here to a clock over there to see whether they match?
     
  20. Nov 14, 2016 #19

    russ_watters

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    Sorry, no. A couple of things;
    1. Relativity is all about comparing what happens in different frames. You always need a "reference frame" and "reference clock", but you can always use any you want. There is no preferred/special one. So no "objective view".

    2. If you bring your reference clock with you, that just makes you stationary with respect to it. And indeed, you notice no problems. That isn't a problem.
     
  21. Nov 14, 2016 #20

    phinds

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    This statement makes it clear that you continue to not understand reference frames. Reference frames are just that ... a REFERENCE. It makes sense to talk about something moving fast or slow IN a reference frame but it makes no sense to talk about a reference frame "moving". Things ONLY move in relation to other things.

    I have to echo what has already been said. You seem convinced that you understand things that you clearly do NOT understand and the best bet for you now is to read more about these concepts before asking questions based on misunderstandings.
     
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