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Question about two-clock experiment

  1. Mar 19, 2003 #1
    I asked this question on the old forum but i didnt get a chance to see if anyone answered it, so i apologize for the repetition:

    Firstly I want to say that I am totally new to theoretical physics so please bear with me. In regards to the two-clock experiment, would it be at all possible that gravity was not affecting the progression of time, but the mechanics of each clock? I ask this not to claim that time is absolute. Just to question the validity of the experiment.

    Thanks
     
  2. jcsd
  3. Mar 19, 2003 #2

    Janus

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    No, it's not possible. It is the difference in gravitational potential that causes the difference in time.

    Even if the clocks were in a perfectly uniform Field, where each clock felt exactly the same force of gravity, the higher one would run faster.

    The experiments performed give results that match this prediction. If it were the force of gravity that each clock felt that caused the difference, you would get different results than the predicted one.
     
  4. Mar 19, 2003 #3

    russ_watters

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    Certainly any experiment can be improperly conducted. But we have some EXTREMELY accurate clocks. If the results were due to bad clocks, the results would be random and you could see the deviation with the clocks sitting next to each other. But they aren't and you can't. The results agree exactly with predictions and comparisons of clocks for calibration yields a high degree of consistency..
     
  5. Mar 20, 2003 #4
    When you say "in a perfectly uniform Field", are you saying there is no difference in gravitational potential between the clocks? If so, how would there be a difference in time?
     
  6. Mar 20, 2003 #5

    LURCH

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    I think the point of the experiment is that there is no difference between those two discriptions. Gravity is affecting the mechanics of everything within the area of gravitational influence. If time is seen as a measurement of the motion of things, then slowing the mechanics of everything is slowing time.
     
  7. Mar 20, 2003 #6
    Re: Re: question about two-clock experiment

    I see a difference. In one, the different clocks are still ticking in the same absolute time frame, they just tick differently. In the time dilation interpretation, one clock is in the future of the other clock. This leads to a problem of cause and effect.
     
  8. Mar 20, 2003 #7
    Re: Re: Re: question about two-clock experiment


    This was what I think I was getting at. I need to think about it alittle more. But I also have another question thats kinda related:

    If time is warped by gravity I can understand how time can differ for an observer in interstellar space opposed to one on a planet, but according to the twin paradox, light speed travel by the interstellar observer would accelerate this time difference. But how would light speed travel affect anything if the speed of light is constant? If the speed of light is the same for all observers, time would appear to flow at the same rate no matter how fast one is travelling,assuming the observer has the same gravitational field acting upon him at all time during travel. Wouldn't this be the case? (Like someone stationary relative to a planet vs. someone orbiting that same planet, at the same distance, at or near the speed of light.)
     
  9. Mar 20, 2003 #8
    Re: Re: Re: Re: question about two-clock experiment

    You can only observe time dilation in a frame different than yours, whether it is because of gravity or because of motion. Problem with interpreting the time dilation as a difference in simultaneity is that you can actually travel to the future and to the past, depending on your frame. If in your frame, the year is 2003 but in the other frame, the year is 2103, when you travel to the other frame, you should have aged 100 years, but once you go back to the other frame, you would become 100 years younger. That's pretty retarded.
     
  10. Mar 21, 2003 #9

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    When I say a uniform field, I mean that there would be no difference in the gravitational force felt by either clock.

    There would still be a gravitational potential difference due to their respect heights in the field.
     
  11. Mar 23, 2003 #10
    Eyesee wrote:"Problem with interpreting the time dilation as a difference in simultaneity is that you can actually travel to the future and to the past, depending on your frame. If in your frame, the year is 2003 but in the other frame, the year is 2103, when you travel to the other frame, you should have aged 100 years, but once you go back to the other frame, you would become 100 years younger. That's pretty retarded."

    Time dilation does not involve traveling into the past. Going to to a certain frame would never make anything younger once it was older, ever.

    Time dilation is limited to slowing the rate of aging of one clock relative to the other. If you know of an interpretation of Relativity theory that actually states time travel into the past, or where once a man reached age 133, he could be 33 again - please post a link here. It would be interesting
     
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