# Time Dilation

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#### mickeyl

##### Guest
For two men, "A" and "B", in a typical thought experiment, the Lorentz transformation says a moving clock runs slower than a stationary one. However, because the electrical charge of an atom is consistent in varying gravitational fields throughout the universe, "B's" moving clock does not run slower. The information just takes longer to reach "A's eyes.

So, "B" is riding in a rocket-ship that has a light-clock, that flashes 10-times per second, and is traveling at .8 the speed-of-light (240x10^9 meters-per-sec); and he passes "A" who is stationary and has a similar flashing-light-clock. After
the initial flash is synchronized, "A" sees his clock flash every .1-seconds (and "B" sees his light-clock flash every .1 second).

But, "B" after .1-second - travels 24x10^6; after 2-second travels 48x, after 3-seconds travels 72x, after 4-seconds travels 96x, after 5-seconds travels 120x10^6.
So: for each .1 sec. - after synchronizing flash = 0 ......... (for "B") .... (for "A")
flash1 = .1 plus 24,000,000/300,000,000 = .08 total ..... (.18sec) ..... (.1sec)
flash2 = .1 plus 48,000,000/300,000,000 = .16 total ..... (.26sec) ..... (.1sec)
flash3 = .1 plus 72,000,000/300,000,000 = .24 total ..... (.34sec) ..... (.1sec)
flash4 = .1 plus 96,000,000/300,000,000 = .32 total ..... (.42sec) ..... (.1sec)
flash5 = .1 plus 120,000,000/300,000,000 =.40 total ..... (.50sec) ..... (.1sec)
.................................................................................... __________________
....................................................................................... (1.52sec) __ (.5sec)
So, "A" sees his light-clock flash 5-times in .5-seconds; but he would see "B's" light-clock flash 5-times at a “slower” 1.52-seconds; (“slower” only because light-photons have to travel further to reach "A's" eyes) - therefore, "B's" clock has not slowed down. The further "B" travels, "A" continues to see "B's" clock flashing/ticking slowly. However, if "B" suddenly stopped "A" would see "B's" clock pulse again every .1-second. If "B" suddenly returned to earth at .8-speed of light (and if "A" could see "B's" light-clock), "A" would see "B's" light-clock pulse speed up, because the light-photons continually have less distance to travel to reach his eyes. But time always remains consistent and it has not slowed for either "A" or "B".

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#### SpeedFreek

##### Guest
At 0.8c, rocketship B would have a gamma of 1.666666... relative to A. Therefore from A's frame of reference, after calculating out light-travel time, A would calculate that B's clock flashed once every 0.166666666... seconds rather than every 0.1 second.

Time-dilation is not an effect of light-travel time. It is not simply a case that the increase in the gap between each photon is caused by increasing light-travel time. If you do the math properly you find there is time-dilation after calculating out light travel time.

You are confusing doppler effect with time-dilation. A would also calculate that Bs clock was ticking every 0.16666666... seconds on the return journey. It is not about what the observer actually sees as he measures it (which is affected by light-travel time), it is about what the observer calculates has happened once both clocks are back in the same reference frame.

After the return journey, when B has come back and both clocks are back in the same frame of reference, B's clock will show less elapsed time than As clock, so it is not an apparent effect, it is an absolute difference. We have proved this in principle - our GPS systems would not work if they did not take time-dilation (after calculating out light-travel time) into account.

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#### origin

##### Guest
mickeyl":88jdafx3 said:
For two men, "A" and "B", in a typical thought experiment, the Lorentz transformation says a moving clock runs slower than a stationary one. However, because the electrical charge of an atom is consistent in varying gravitational fields throughout the universe, "B's" moving clock does not run slower. The information just takes longer to reach "A's eyes.

So, "B" is riding in a rocket-ship that has a light-clock, that flashes 10-times per second, and is traveling at .8 the speed-of-light (240x10^9 meters-per-sec); and he passes "A" who is stationary and has a similar flashing-light-clock. After
the initial flash is synchronized, "A" sees his clock flash every .1-seconds (and "B" sees his light-clock flash every .1 second).

But, "B" after .1-second - travels 24x10^6; after 2-second travels 48x, after 3-seconds travels 72x, after 4-seconds travels 96x, after 5-seconds travels 120x10^6.
So: for each .1 sec. - after synchronizing flash = 0 ......... (for "B") .... (for "A")
flash1 = .1 plus 24,000,000/300,000,000 = .08 total ..... (.18sec) ..... (.1sec)
flash2 = .1 plus 48,000,000/300,000,000 = .16 total ..... (.26sec) ..... (.1sec)
flash3 = .1 plus 72,000,000/300,000,000 = .24 total ..... (.34sec) ..... (.1sec)
flash4 = .1 plus 96,000,000/300,000,000 = .32 total ..... (.42sec) ..... (.1sec)
flash5 = .1 plus 120,000,000/300,000,000 =.40 total ..... (.50sec) ..... (.1sec)
.................................................................................... __________________
....................................................................................... (1.52sec) __ (.5sec)
So, "A" sees his light-clock flash 5-times in .5-seconds; but he would see "B's" light-clock flash 5-times at a “slower” 1.52-seconds; (“slower” only because light-photons have to travel further to reach "A's" eyes) - therefore, "B's" clock has not slowed down. The further "B" travels, "A" continues to see "B's" clock flashing/ticking slowly. However, if "B" suddenly stopped "A" would see "B's" clock pulse again every .1-second. If "B" suddenly returned to earth at .8-speed of light (and if "A" could see "B's" light-clock), "A" would see "B's" light-clock pulse speed up, because the light-photons continually have less distance to travel to reach his eyes. But time always remains consistent and it has not slowed for either "A" or "B".
Your example indicates that you believe that there is only an apparent time dialation as the ship recedes from the observer. If that were true then a ship approaching the observer would show a time constriction based on your example. Is this what you believe?

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