ahrkron
Staff Emeritus
Science Advisor
Gold Member
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Originally posted by Martin Miller
There are only two problems with this, namely, you have yet to
prove that the pulses travel at equal speeds wrt the clocks,
If both clocks are identical, there is no reason to expect otherwise. Anyway, this potential problem is easy to overcome: just reduce the length of the "Y" branches as much as possible. Clearly, there is no reason why this coudln't be zero. Ultimately, you can even attach the two clocks to, say, both sides of the same circuit board, so that they share the exact same input lines (so there are not two pulses).
and you have yet to provide a means of verifying absolute synchronicity.
I did. You just need to let the two clocks run for, say, a day, and then send the stop signal. At that moment, both clocks are programmed to store their final times in memory devices, and both are displayed in a screen. If both show the same number, you know that they are in sych down to one count in a day worth of counts.
As an example, say that they count once per nanosecond (ns) (which is not much; the computer I'm working on has a 2GHz clock, i.e., its clock ticks twice every nanosecond). In a day, you have a total of 86400 seconds, which makes 8.64x10^13 ns. Adjust anything you need until, after a day, you get the two clocks to get the same count. Then you know that they are syncronized to one part in 8.64x10^13. Not bad at all, and good enough to make the measurement for the speed of the space shuttle (8 km/s, which gives a time dilation difference of the order of 10^-9; i.e., the potential experimental error is four orders of magnitude smaller than the difference you want to measure! that allows for a very good measurement)
And, as I said, but as you seemingly ignored, _if_ you had actually
discovered a means of absolutely synchronizing clocks, then you
would be the first.
Time synchronization is not the problem you make of it. There are high speed networks all around us these days. In order for them to work properly, transmitters and receivers need to have similar speeds and to exchange signals at the right times.