NowThatWeKnow Posted May 8, 2009 Posted May 8, 2009 Not moving with respect to what? Keep in mind that there is no such thing as an absolute reference frame. I almost said that but I know he does know it because he used it earlier to support his argument.
swansont Posted May 8, 2009 Posted May 8, 2009 Not synchronized — the clock will be behind the Master clock. (I prefer that term to universal) It will run at the same rate when it's in the same inertial frame, which means it is syntonized, but it will not read the same number. Synchronized means same rate and same reading, i.e. synchronized ideal clocks remain synchronized if unperturbed. I have to correct this. Synchronized means the same reading. The rates can be different if they are in different frames, so what I said above only applies in the same reference frame.
NowThatWeKnow Posted May 8, 2009 Posted May 8, 2009 I have to correct this. Synchronized means the same reading. The rates can be different if they are in different frames, so what I said above only applies in the same reference frame. The speed of a clock could be synchronized without the time being synchronized (in the same frame), right? I think you are saying that the GPS satellite clocks are synchronized to Earth clocks but running at different speeds and in different frames. Is that right?
gib65 Posted May 8, 2009 Author Posted May 8, 2009 But I think they both could have a master clock (or call it what you want) that is synchronized with each other. The clocks on the GPS satellites are a good example of clocks adjusted for both GR and SR so they are synchronized with earth clocks. Future technology will allow the clocks to maintain synchronization during acceleration. At this point I can use my mind to imagine any technology necessary to help me understand relativity. I see what you mean about the satellites. In that sense, yes, both twins could have their clocks synchronized (I personally wouldn't call them Master Clocks though). Not moving with respect to what? Keep in mind that there is no such thing as an absolute reference frame. Not moving with respect to whatever reference frame you've chosen. I take it as a general rule in relativity that if one says 'not moving' that means with respect to the chosen reference frame.
swansont Posted May 8, 2009 Posted May 8, 2009 The speed of a clock could be synchronized without the time being synchronized (in the same frame), right? I think you are saying that the GPS satellite clocks are synchronized to Earth clocks but running at different speeds and in different frames. Is that right? Making them the same frequency is syntonized, as I said earlier. If you synchronize clocks running at different rates they will lose synchronization, as with two clocks in different frames. GPS clocks are set to run at earth clock speeds by adjusting their frequency.
NowThatWeKnow Posted May 8, 2009 Posted May 8, 2009 (edited) Making them the same frequency is syntonized, as I said earlier. If you synchronize clocks running at different rates they will lose synchronization, as with two clocks in different frames. GPS clocks are set to run at earth clock speeds by adjusting their frequency. Thank you for elaborating. I was trying to keep it simple and thinking of synchronized clocks in different frames as analogue hands moving over the same numbers simultaneously with no regard to how it was done. Merged post follows: Consecutive posts mergedI see what you mean about the satellites. In that sense, yes, both twins could have their clocks synchronized (I personally wouldn't call them Master Clocks though)... Sometimes I think we are looking at the same thing from different angles and then arguing with ourselves. As far as "Master Clocks", swansont has convinced me to use it, at least until something better is suggested. Edited May 8, 2009 by NowThatWeKnow Consecutive posts merged.
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