Space-time curvature is incorrect

Discussion in 'Physics & Math' started by Frencheneesz, Aug 26, 2002.

  1. zanket Human Valued Senior Member

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    3,777
    Prosoothus:

    Experiments that measured the one-way speed of light:

    In 1676, Olaus Roemer measured the speed of light using the moons of jupiter. His prediction was 200,000 km/s.

    In 1728, James Bradley measured the speed of light using stellar aberration. His prediction was 301,000 km/s.

    I believe James R was referring to experiments confirming time dilation and length contraction, not experiments measuring the speed of light. Nevertheless, a confirmational experiment that involves a one-way trip is that of the muon.
     
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  3. Prosoothus Registered Senior Member

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    zankat,

    Oops!! My statement was a little to vague.

    I meant to say that no experiments have been done that measure the one-way speed of light in a moving frame of reference (that confirm that the speed of light remains c in a moving frame of reference).

    There have been experiments that indicate that time "slows down" at relativistic speeds, but these experiments may be flawed if you take into consideration that the principle of invariance of light may be wrong.

    Tom
     
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  5. (Q) Encephaloid Martini Valued Senior Member

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    Crisp offers:

    However, we can try to explain as much as we want, as long as you don't drop your ungrounded blocking of anything that is related to theory of relativity (regardless whether it is correct or not), I am afraid that that discussion would be a waste of time...

    Prosoothus counters:

    There have been experiments that indicate that time "slows down" at relativistic speeds, but these experiments may be flawed if you take into consideration that the principle of invariance of light may be wrong.

    Oh well, at least Crisp made the offer.
     
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  7. Prosoothus Registered Senior Member

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    Crisp,

    Let me explain so that you don't waste your time.

    There are two clocks, one that is stationairy on Earth, and one in my spaceship. I fly towards the stationairy clock at a speed of .90c in my spaceship. When the clock in my spaceship is right above the stationairy clock they become synchronized, at that exact moment, I turn on my flashlight and point it forward(in the direction of my motion). I continue to fly away at .90c for 1 second of the stationairy clock. How fast is the beam of light moving in my frame of reference??

    In the stationairy clock's frame of reference, I am 270,000 km away from the clock after one stationairy second, and the beam of light is 300,000 km away from the stationairy clock after one stationairy second. That means that after 1 stationairy second, the light is 30,000 km away from me in the stationairy clock's frame of reference. To summarize:

    t=1 second
    L=30,000 km

    Now let's find out the time and distance in my frame of reference:

    Because time slows down for me since I'm travelling at relativistic speeds, every second of the stationairy clock, 0.436 seconds pass on my clock. Therefore:

    t(me)=.436 seconds

    Because length contracts for me since I'm travelling at relativistic speeds, every 1 km of the stationairy clock's frame of reference is contracted to 0.436 km in my frame of reference. So 30,000 km in the stationairy clock's frame of reference is converted to:

    L(me)=13,100 km

    Therefore, the light is 13,100 km away from me in .436 seconds in my frame of reference. To calculate the speed that the light is travelling relative to me I divide the length by the time:

    v=L/t
    v=13,100/.436
    v=30,000 km/s

    I thought the speed of light in my frame of reference was supposed to be 300,000 km/s.

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    It appears that the light is travelling ten times slower than it should be.

    Tom
     
    Last edited: Sep 13, 2002
  8. zanket Human Valued Senior Member

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    Prosoothus:

    You are using circular logic. You use "Because time slows down for me since I'm travelling at relativistic speeds" and "Because length contracts for me since I'm travelling at relativistic speeds," in your logic to show that light's speed is variable. But time slows and length contracts because light's speed is constant. Put differently, you are using a = b to show that a <> b.
     
  9. Crisp Gone 4ever Registered Senior Member

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    1,339
    Hi Tom,

    As many of us explained extensivily in one of the previous major threads on relativity, the formulas for time dilatation and length contraction you use to calculate your numbers are not valid in this situation.

    Yes, I know I (we?) used them at first aswell, until I (we?) saw where it went wrong. However, ever since those formulas were listed, along with the conditions where they are valid, you keep using them in situations where these conditions are not met.

    I'm sorry, but I am afraid it doesn't work that way

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    .

    Bye!

    Crisp
     
  10. Prosoothus Registered Senior Member

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    zanket,

    I used the standard formulae for length contraction and time dilation to prove that the speed of light is not c in the spaceship's frame of reference.

    If I did it in reverse, and assumed that the speed of light is c relative to the spaceship, and calculated length contraction and time dilation from that fact, my formulas for length contraction and time dilation wouldn't match the standard formulas. Not only would they not match the standard formulas, but the formulae would change based on the direction in which I would be pointing my flashlight.

    If you wan't to try to figure out the length contraction and time dilation formulae in my thought experiment, based on the assumption that the speed of light is c relative to the spaceship, please feel free to try. But beware, I will use your formulae against you.

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    Tom
     
  11. Prosoothus Registered Senior Member

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    Crisp,

    Are you saying that:

    A) For every second of the stationairy clock, 0.436 DOES NOT pass for the clock on my spaceship.

    B) Every 1 km DOES NOT contract to 0.436 kilometers in my spaceships frame of reference.

    C) A and B

    If my clock does not show .436 seconds after 1 second of the stationairy clock, what time does it show??

    If one km doesn't contract to .436 kilometers in my frame of reference, what is the contraction ratio??

    Crisp, be carefull how you answer my two questions. I will use your answers against you.

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    Tom
     
  12. zanket Human Valued Senior Member

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    Prosoothus:

    You used the results invalidly. For example, your “t(me)” is from the stationary clock’s frame, whereas your “L(me)” is from the ship’s frame. (From the ship’s frame, while the stationary clock elapses 1 second, the ship’s clock elapses 2.294 seconds.) You assumed that the stationary clock and the ship would simultaneously observe the light pulse reach a coordinate point, which is precluded by the distortion of time and space between them.
     
  13. Crisp Gone 4ever Registered Senior Member

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    1,339
    Hi Tom,

    "Crisp, be carefull how you answer my two questions. I will use your answers against you."

    I am sure you will

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    . Look, I am going to calculate your problem for myself first, verify it about four times and then I'll post what I came up with. That will probably be somewhere later today (have to go to work first).

    Bye!

    Crisp
     
  14. Prosoothus Registered Senior Member

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    1,973
    zanket,

    If that's the way you prefer it. In the stationairy frame of reference:

    t=1 second
    L=30,000 km

    In the spaceship's frame of reference:

    t(me)=2.29 seconds
    L(me)=13,100 km

    When you divide 13,100 km by 2.29 seconds, you get:

    v=L/t
    v=13,100 km/2.29 seconds
    v=5,720 km/s

    5,720 km/s is still nowhere close to 300,000 km/s

    This is a thought experiment in which I intentionally exclude any kind of "observation". In order to "observe" something, light must make a roundtrip to an object and back. When time dilation and length contraction is applied to a roundtrip of light, it always gives the result that the speed of light is equal to c in any inertial frame of reference. That's why the thought experiment I suggested only deals with the one-way trip of light.

    As I stated before, I believe that the omnidirectional speed of light is c only in the absolute frame of reference. The one-way speed of light in a moving frame of reference, relative to the moving frame of reference, increases or decreases dependent on the speed of that frame of reference relative to the absolute frame of reference. If you have a roundtrip of light, where one is faster and one is slower than c relative to the moving frame of reference, they average out to c, minus a variation. This variation is compensated for by the formulae for length contraction and time dilation so that the roundtrip speed of the light always averages out to c.

    However, even though the the length contraction and time dilation formulae nicely compensate for the variation resulting from the round trip of light, these same formulae can't make the one-way speed of light in the same moving frame of reference equal c. This is what I'm attempting to demonstrate with my experiment.

    Tom
     
  15. zanket Human Valued Senior Member

    Messages:
    3,777
    Prosoothus:

    The solution:

    The 300,000 km distance that the stationary clock observes is observed by the ship to be (300,000 km * 43.6% distortion) = 130,767 km. Light covers that distance in 0.436 seconds. As observed by the stationary clock, the ship’s elapsed distance is 90% of the elapsed distance of the light pulse. The ship is 10% of the light’s elapsed distance away from the light pulse. 10% of the ship’s observed 130,767 km is 13,077 km. 10% of 0.436 seconds is 0.0436 seconds. Light traveling 13,077 km per 0.0436 seconds is traveling 300,000 km/s.
     
  16. James R Just this guy, you know? Staff Member

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    39,397
    Tom,

    I am disappointed that you appear to have learnt nothing from our previous conversations. Several people, including myself, carefully took you through your hypothetical situation, explaining all the relevant physics.

    Obviously you either could not, or (more likely) did not want to understand the explanations given. What's worse is that you are now misrepresenting those explanations.

    <i>I know that you know that one-way trips of light are a problem with relativity.</i>

    They are no problem - as I have maintained all along.

    <i>Do you remember when when I asked you to find the solution to the two-flashlight experiment? You and Crisp were quick to point out that the experiment was somehow an exception.</i>

    No. We pointed out that it was a straightforward application of the Lorentz transformations.

    <i>The reason it was an exception was because SR was NEVER meant to deal with one-way trips of light, it was only meant to deal with roundtrips of light.</i>

    Neither of us said any such thing.

    <i>If you remember, the only solution to the "experiment" was to have multiple time dilations(as you concluded) or multiple length contractions in the same frame of reference in order to preserve the principle of invariance of light.</i>

    Wrong.

    <i>But I know that you are a smart guy, and you would never accept the fact that there can be multiple time dilations or length contractions in the same frame of reference.</i>

    That's right. Your problem dealt with multiple reference frames, not a single one.

    <i>After all, wouldn't all clocks in the same frame of reference indicate the same time??</i>

    If synchronised, yes.

    <i>However, when you attempt to convert a one-way trip of light from one frame of reference to another, using the classical formulae for length contraction and time dilation, you get a result that indicates that SR must be wrong.</i>

    No. You don't know how to apply those formulae correctly. I previously asked you for what you consider would be precise definitions of the terms in the time dilation and length contraction equations. No satisfactory response was forthcoming. I do not believe you understand the formulae. The Lorentz transformations, being a step beyond the simple formulae, are no doubt equally out of your reach.

    Having already addressed your scenario in depth, I will not now do it again.
     
  17. Prosoothus Registered Senior Member

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    1,973
    Zankat,

    Nice try!!

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    Everything so far is correct, but here's where you messed up:

    The ship was travelling the same amount of time as the light pulse. Therefore, the time would still be .436 seconds, and not .0436 seconds. If you place the .436 seconds in your formula, you will find that the light is travelling only 30,000 km/s in the ship's frame of reference.

    Tom
     
  18. Prosoothus Registered Senior Member

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    James,

    I have an excellent memory. I remember clearly what you said.

    My comment:

    Your reply:

    It appears that you have a problem remembering our conversation. Let me refresh your memory:

    I was discussing an experiment with two beams of light: one moving forward (in the same direction of the spaceship) and one moving backwards (in the opposite direction of the spaceship). Even though the trips of both beams took 1 second in the stationairy clocks's frame of reference, you applied two seperate time dilations to each of the beams, in the same frame of reference, because they were seperate events.

    For the forward beam you claimed:

    And for the backwards beam you claimed:

    To summarize, you claimed that even though the trips of both beams took 1 second in the stationairy frame of reference, they took 0.229 seconds AND 4.35 seconds in the spaceship's frame of reference. Believe it or not, you applied two time dilations in the same frame of reference. If you don't believe me, here is your post:

    http://www.sciforums.com/showthread...&perpage=20&highlight=flashlight&pagenumber=7

    But I did learn something from your post. In my most recent thought experiment, I included an atomic clock in my spaceship. My atomic clock will tell me if 0.229 seconds passed, 4.35 seconds passed, or something completely different. The funny thing is that my clock will only say one time, so at least one of your time dilation values will be wrong.

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    Can you guess what time my clock will indicate?

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    I understand.

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    Tom
     
  19. (Q) Encephaloid Martini Valued Senior Member

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    Prosoothus

    To summarize, you claimed that even though the trips of both beams took 1 second in the stationairy frame of reference, they took 0.229 seconds AND 4.35 seconds in the spaceship's frame of reference. Believe it or not, you applied two time dilations in the same frame of reference.

    James R said:

    There were two time dialtion formulae applied because there were two events from the moving observers frame of reference relative to the stationary observer. Grasp this concept and you will understand the flaw in your argument.
     
  20. Prosoothus Registered Senior Member

    Messages:
    1,973
    Q,

    Let me repeat myself, there is no "observation" in thought experiment I provided because when there is "observation" then simultaneity must be taken into consideration. James is correct when he indicated simultaneity is relative.

    To better understand my thought experiment, pretend that you are God and can be at any location instantly. My thought experiment assumes this by mathematically extrapolating the results instead of measuring them.

    The fact is that if something that takes 1 second in the stationairy clock's frame of reference and .435 seconds in a moving frame of reference, everything that takes 1 second in the stationairy clock's frame of reference will take .435 seconds in the moving frame of reference. But just because two events happen at the same time doesn't mean that an "observer" will witness these events at the same time.

    For example, two stars can explode at the same time, but an observer will witness these events at different times if one star is farthur away from him than the other. This is exactly the reason why I'm not using "observation" in my thought experiment.

    Tom
     
  21. (Q) Encephaloid Martini Valued Senior Member

    Messages:
    20,855
    Prosoothus

    To better understand my thought experiment, pretend that you are God and can be at any location instantly.

    In other words, posit an absolute frame of reference. Anything is possible if you pretend you're God. However, it is quite meaningless when discussing real science wherein your analysis no longer remains a thought experiment. It now becomes pure fantasy and enters the realm of scifi.

    My thought experiment assumes this by mathematically extrapolating the results instead of measuring them.

    Shouldn't they be one in the same ?

    This is exactly the reason why I'm not using "observation" in my thought experiment.

    That said, you've successfully reduced this entire discussion to moot.
     
  22. Prosoothus Registered Senior Member

    Messages:
    1,973
    Q,

    You misunderstood my post.

    I'm only interested in when an event happens. I'm not interested in when an observer sees an event happen.

    No. Using math, you can figure out the exact time that an event occured. If you measure an event, there is a delay between when the event occured and how long it takes the light from the event to reach you.

    Tom
     
  23. zanket Human Valued Senior Member

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    3,777
    Prosoothus:

    That is from the ship's frame. But in your story the 30,000 km is measured from the stationary clock's frame and is 10% of the distance the light pulse traversed. The ship measures the light pulse's distance from the ship to be 100% of the distance the pulse traversed, not 10%. In the ship's frame, the 10% value is arbitrary. So if I am to take 10% of the distance the ship measures, then I must take 10% of the time the ship measures as well.
     

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