[part 4 of 4] Wheeler is saying is that the distant clock must read the time x/c to get c for light's one-way speed, and it doesn't matter if this reading is placed on the clock when it's started by the light signal, or if it's placed there 10 years prior. However, since Wheeler (very conveniently, in my humble opinion) did not talk about more than one frame, it is impossible to see the truth of the matter. (It is also impossible to show c invariance unless one uses at least two frames.) And the truth of the matter (as my two-frame tale shows) is that Einstein's desired c invariance simply cannot happen, not even on paper, because it invalidly involves clocks that are started at absolutely different times having to read the same time (x/c) when started. This is a direct and clear conflict with reality on the part of Einstein's "postulate." Maybe all of the above would warrant re-opening the thread. If so, then perhaps you could request that.
[part 3 of 4] Wheeler & Taylor's book _Spacetime Physics_, 1963 edition, page 18: "Pick one of the clocks in the lattice as the standard of time and take it to be the origin of a coordinate system, Start this reference clock with its pointer at t = 0. At this instant let it send out a flash of light that spreads in all directions. ...This is the reference flash. When the reference flash gets to a clock 5 meters away, we want that clock to read 5 meters of light-travel time. So an assistant sets that clock to 5 meters of time long before the experiment begins, holds it at 5 meters, and releases it only when the reference flash arrives. When [the] assistants at all the clocks in the lattice have followed this procedure (each setting his clock to a time in meters equal to his own distance from the reference clock and starting it when the light flash arrives), the clocks in the lattice are said to be synchronized."
[part 2 of 4] The only way for both sets of observers to get c for light's one-way speed across their tables is for their clocks to record the time x/c, do you agree? And of course, if the origin clocks both read zero when the light signal is emitted at them as they meet in passing, then the two distant clocks must both read the time x/c when the light ray reaches them. That is, the two distant clocks must both read the time x/c whenever they are "hit" by the light signal. We are not concerned at all about when the right ends of the tables pass each other. All we are concerned with is trying to get both sets of observers to obtain the same one-way light speed as called for by Einstein's second postulate. When I saw your opening remark, I immediately sensed that you really need to read the definitive definition of Einstein's definition of synchronization. After reading that, you would definitely not say that "the right-end clocks must read zero when the light ray reaches them."
(Pete. I just now discovered your message.) [my reply: part 1 of 4] [u wrote:] >It seems that the right-end clocks haven't been started, so >they must read zero when the light ray reaches them. >When do the right-end clocks start? >When the right-ends of the tables pass each other? >If so, don't forget about length contraction... Length contraction is not involved because all that is used is the measured distance between clocks in each frame using a ruler that is at rest in the frame in which the measurement is being made. No one is measuring anyone else's ruler or distance. For example, let's say that the observers on Table A used their ruler and found the distance between their clocks to be 100 yards; likewise, the Table B observers found the distance between their clocks to be 100 yards.
Hi timewarp, prometheus locked the thread before I saw your reply. You said: ---------- Go to the gymnasium of a large school. Place a light on a pole. Get two long, narrow equal-length (by construction) tables. Place an unstarted clock at each end of each table. (4 clocks) Align one table's left end with the light pole. Slide the other table steadily toward the pole from the left. Whenever the tables' left ends meet at the light, start both left clocks on zero. According to special relativity theory, each right-end clock must read the time x/c whenever the light ray reaches it. ---------- It seems that the right-end clocks haven't been started, so they must read zero when the light ray reaches them. When do the right-end clocks start? When the right-ends of the tables pass each other? If so, don't forget about length contraction...
