On Einstein's explanation of the invariance of c

Discussion in 'Pseudoscience Archive' started by RJBeery, Dec 8, 2010.

  1. phyti Registered Senior Member

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    732
    RJBeery,
    Here's a simple problem for you.
    Begin with two car drivers A & B at the starting line. A leaves at a constant speed of 50 mph. After 1.2 minutes, B leaves in the same direction at a constant speed of 60 mph. How long will it take B to catch A who has a 1 mile lead?
     
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  3. Motor Daddy Valued Senior Member

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    A meter is the distance traveled by light in vacuum in 1⁄299,792,458 of a second. Light travel time is distance, period! Do you understand that concept? Evidently not
     
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  5. Motor Daddy Valued Senior Member

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    5,425
    Are you trying to divert attention away from the fact that you can't tell me why I'm wrong?
     
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  7. RJBeery Natural Philosopher Valued Senior Member

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    Err what? Why is this question directed at me? You need help with your homework or something?

    If we're ignoring relativistic effects here the answer is 6 minutes.
     
  8. phyti Registered Senior Member

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    732
    If you send a signal to each clock for a reading, they will return different times. The frame is moving, but you don't know the speed.

    If you place the clocks then send a signal to start each, they will return equal times but lag the center clock.
     
  9. RJBeery Natural Philosopher Valued Senior Member

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    Motor Daddy, would your world predict redshifting depending on viewing perspective of the light source? Do we experience redshifting depending on viewing perspective of the light source?
     
  10. Motor Daddy Valued Senior Member

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    5,425
    Do you not understand what I typed?

    I just sync'd watches at each coast to read the same time simultaneously, as if they are in a single time zone.

    I am measuring the time it takes a light signal to go from one coast to another, each way, individually. I am measuring how much time it takes for light to travel in each direction.
     
  11. Motor Daddy Valued Senior Member

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    If the distance between you and the source changes, a shift occurs. Do you change distance between coasts? No.
     
  12. RJBeery Natural Philosopher Valued Senior Member

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    4,222
    Wait a minute you are contradicting yourself. Put a lamp post in the middle of our 180mph laterally-moving country. Turn it on. Would its light take the same amount of time to reach the coasts or not? Would the light reaching each coast be red/blue shifted or the same frequency?
     
  13. phyti Registered Senior Member

    Messages:
    732

    RJBeery, post#3

    To distinguish between propagation speed of light and closing speed of light.
    B moves at 50 mph relative to the road.
    A moves at 60 mph relative to the road.
    Closing speed is 10 mph relative to the cars, and is the rate of change of the distance between them, distinctly different from the car speeds.
    Substitute c (in mph)for A's speed, and (c-50)is the closing speed.

    In summary: light always moves at c independently of material objects, and closing speed is a function of the objects speed.
     
    Last edited: Dec 15, 2010
  14. Motor Daddy Valued Senior Member

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    5,425
    I'm not contradicting myself, you don't understand it.

    No, it would not reach each coast in the same amount of time.

    If the source was throwing baseballs at the rate of 1 per second, and your distance from the source doesn't change, you will have 1 baseball per second hit you, regardless of the absolute velocity.
     
  15. RJBeery Natural Philosopher Valued Senior Member

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    Phyti when you're discussing "closing speed" of a light beam you must declare what frame you are calculating from. Otherwise you are just as wrong as Motor Daddy and I barely have enough time dealing with one of him.
    So the light propagation time would differ to each coast, but the received frequency at each coast would be the same? You realize you're rewriting Physics, right?
     
  16. Motor Daddy Valued Senior Member

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    5,425
    I like to think of it as putting it on the right track again. It's been astray long enough!
     
  17. phyti Registered Senior Member

    Messages:
    732
    How do you do that (in red)?
     
  18. Motor Daddy Valued Senior Member

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    5,425
    With sync'd watches it's easy, just send a light signal and record the time of departure, and record the time of arrival on the other coast from the other clock. Since the clocks are sync'd, you can tell how much actual time has elapsed.

    If the light is sent at 12:00:00 from one coast, and it arrives at the other coast at 5:00:00, the light took 5 hours to get there. Simply perform the light travel time measuring in the opposite direction to get the opposite direction of travel time.
     
  19. RJBeery Natural Philosopher Valued Senior Member

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    4,222
    Do you recant the above statement? You realize it contradicts your 5.26 hour round-trip calculation, right?

    What you're saying is that round-trip light travel across a given length will always give the same answer, UNLESS the absolute velocity of the object being measured is greater than 1/2 c, at which point 1 leg of the trip is longer than the entire expected trip length if we were at absolute zero velocity. At that point, you are arbitrarily putting yourself back into the zero velocity frame to calculate "what's going on".
     
  20. Neddy Bate Valued Senior Member

    Messages:
    2,548

    Clock at A says 12:00
    Clock at B says 12:30
    I send a light signal from A to B to A, and when it arrives back at A, clock A says 12:01. Round trip time is 1:00.



    Clock at A says 12:05
    Clock at B says 12:35
    I send a light signal from B to A to B, and when it arrives back at B, clock B says 12:36. Round trip time is 1:00.


    The round trip time in the first case is the same as the round trip time in the seconds case. So, according to your logic, clocks A and B are in synch?
     
  21. Motor Daddy Valued Senior Member

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    5,425
    Yes, I recant that, as I didn't mean the actual numbers would add to one, just that one way would be more, and one way would be less than .5. I got a little carried away there.

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  22. Neddy Bate Valued Senior Member

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    2,548
    What was your clue? Was it when I said, "The clocks might have gone out of synch?"

    But if the one-way time is 2.63 in both directions, the round trip time is still 5.26. What do you think happened, if the clocks din't go out of synch? Do you think the continent suddenly came to absolute rest?
     
  23. Motor Daddy Valued Senior Member

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    5,425
    Use the other method of syncing I describe. You don't understand the relevance of one watch's rotational velocity changing. If the rotational velocity changes, they will not measure the same elapsed times, as one will tick faster than the other, so it will say more time has elapsed than the other one will.

    If you have a hard time understand that way, simply mount a watch at each coast on a pole with the time reading 12:00:00 and the plastic in place so the watches are inop. Now tie a string from one plastic to the other. Place a crank in the middle of the string in such a fashion that when you crank the handle, it pulls each plastic out simultaneously, hence starting each watch simultaneously.

    Gee, I deliver a truckload of horny girls to you, and you ask me if they are naked. Do I have to do everything for you?

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    Last edited: Dec 15, 2010

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