Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Lorentz Vs. Einstein Who Wins?

  1. Mar 20, 2012 #1
    Lorents and Einstein both made equations to describe time dialation. One of these equations was used in quantum mechanics, the other equation was then used in cosomology. These equations then made two new areas in physics. One describes one area of physics and the other describes an area of physics, but neither can be used to describe the other. This has raised a lot of questions to which one may be wrong, or what one is more right than the other. Then I noticed something, these two equations are written to different ways but do not equal each other.

    I have seen Einsteins equation written as Δt'=Δt/√(1-v^2/c^2)

    I have seen the Lorentz equation written as Δt=Δt'γ
    where γ=1/√(1-v^2/c^2)

    These two equations do not equal each other. The time variebles are in different locations in the equation? Simply a typo, or is one of the equations more right than another?

    Then if there are in fact the same equation that brings about two branches of science create mathmatics that does not work with each other?
  2. jcsd
  3. Mar 21, 2012 #2
    Lorentz Ether Theory is physically equivalent to Special Relativity. Perhaps you'd care to explain what Δt and Δt' are supposed to represent in the equations you posted.

    None of this is true.
  4. Mar 21, 2012 #3
    ΔWell in Einsteins relativity Δt is the change in time of an observer at rest, and Δt' is the change in time of an object in motion. You get a larger value for dialated time for the object in motion so then you have to take the inverse of the answer to find the proper time.

    In Lorentz transformation Δt is the proper time and Δt' is the proper time of a particle in motion. There is no need to take an inverse. But the inverse of one equation is not equal to the inverse of the other equation.
  5. Mar 21, 2012 #4
    I wish it wasn't.
  6. Mar 21, 2012 #5
    Like I said, LET is equivalent to SR; they do not make different predictions. The discrepancy is coming from you misinterpreting things.

    Say you're at rest in some reference frame and there's some particle traveling at velocity v down your x-axis. If you measure some time Δt separating two events the particle passes through, then the particle will measure Δt' = Δt√(1-v^2/c^2). LET and SR do not differ on this.
  7. Mar 21, 2012 #6
    It isn't. There's no need for wishes.
  8. Mar 21, 2012 #7
    Put a value into that and then put the same value into the other equation and take the inverse and see what you get, I dare you....
  9. Mar 21, 2012 #8
    You're not listening to me. The equation Δt' = Δt√(1-v^2/c^2) is the same prediction made by BOTH SR AND LET.

    You can call the time you measure Δt' and the particle time Δt if you want, and then the other equation is correct. This doesn't change the meaning.

    If you're here because you're confused and want to learn, great. You're coming off as arrogant and argumentative, and you continue to assert your blatantly false ideas.
  10. Mar 21, 2012 #9

    Just let it roll over for another hundred years when someone learns to do algebra. The time variebles are reversed in this enyclopedia even, in no way shape or form does takeing the inverse exchange variebles in an equation. Nothing in either of these equations can be substituted from anything else in the other. It is even written that way in text books that introduce relativity in physics 101. It doesn't make the same prediction, it would be like getting the time variebles missassingned in an equation.
  11. Mar 21, 2012 #10
    I'm done with you. You're not even bothering to try to understand what I said; it seems you'd rather just dig yourself a deeper hole.
  12. Mar 21, 2012 #11
    Good thread. I'd read it again. BTW John, they do make equivalent predictions, you're misinterpreting what the theories mean.
  13. Mar 21, 2012 #12
    I would like to see someone show me how they do. I think they would just end up proving to themselves that they don't. They would only come as close to an answer where you just switched the variables and decided that you could correct it by just takeing the inverse. I don't even know if or where there is any mathmatical rule that says you can do this.
  14. Mar 21, 2012 #13
    You have written the Lorentz equation wrong. The wikipedia page on Lorentz Factors states it as t'=yt. Written like this the two equations are completely identical.
  15. Mar 21, 2012 #14


    Staff: Mentor

    Yes, just a typo. The equations of Lorentz and Einstein are the same.
  16. Mar 21, 2012 #15
    If t' is a moving frame, you must have Dt= gamma*Dt'
  17. Mar 21, 2012 #16
    I thought I saw a video in another thread where it was different. Then there was talk about the proper time, that wasn't the same. Where does the equation that elfmotat gave come from? Or is that also a typo, lol.
  18. Mar 21, 2012 #17

    D H

    User Avatar
    Staff Emeritus
    Science Advisor

    There is no way to distinguish Lorentz ether theory and special relativity experimentally because the two formulations will always predict the same results for any experiment. The two formulations only differ in the underlying assumptions used to arrive at the same predictions.

    So if the two formulations always yield the same results, why is it that special relativity is taught while Lorentz ether theory is largely ignored?

    One answer is that the underlying assumptions of special relativity are much cleaner, much less ad hoc than those of LET. Special relativity assumes that the laws of physics are the same in all inertial frames, assumes that the speed of light is the same to all inertial observers, and assumes that spacetime forms a smooth manifold. The assumption of a constant of the speed of light is weird, but that is what Maxwell's equations and what experiment says is the case.

    LET assumes the Lorentz transformation and assumes an aether frame in which the electromagnetic waves propagate. This aether frame is undetectable thanks to the Lorentz transformation. This is not physics as there is no way to test this assumption. Another problem is that there is no reason for this aether or aether frame. Physicists in 1905 did not know about quantum mechanics. They assumed that electromagnetic waves were like every other wave phenomena they knew of -- some medium was required to transport the waves. Photons travel just fine through vacuum. The need for this aether disappeared with quantum mechanics.

    Yet another problem with LET is that special relativity merges well with quantum mechanics in the form of quantum electrodynamics and generalizes nicely to general relativity. LET does neither.
  19. Mar 21, 2012 #18
    Who discovered that you can find the proper time by taking the reciprocal of the number of times a clocks pendelum swings? I find it to be a strange concept as I have never seen it used before in any other method of calculation.
  20. Mar 21, 2012 #19
    You can't. What made you think you could? 1/t doesn't even have units of time - it has units of frequency.
  21. Mar 21, 2012 #20
    In SR you find the proper time of an object traveling at relative speed by taking the reciprocal of the final answer in order to get a smaller value. I was wondering if this is something that works in Galilean relativity or was it introduced in SR? I guess you are thinking of LET and not SR. In SR gamma is derieved by using a light clock. I don't see why a normal clock would work this way if you did not consider time dialation.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook