The first 90 posts of this thread were a sidetrack culled from another thread: [post=3068386]Basic Special Relativity Question[/post]. The sidetrack originated when Tach said that while the relativity of simultaneity is real, it can't be measured even in principle. I maintain that it can in principle be measured, but that I doubt the feasibility in practice. You could just answer it. Then the time wouldn't be wasted. Do you think RoS is physically meaningful? Surely not, since you think it can't be measured. But then why do you think it is real? There's not much to think about, it's a pretty trivial experiment in principle. But, it's not practical. You're not going to get a precision synchronizable clock running on a rail at 100km/s. Try this: Place two clocks 1000 km apart. Synchronize them using Einstein synchronization. Beside each clock is a rail, on which runs another clock (two rails, two clocks, 1000km apart). The rails are long enough that the clocks on the rails can be accelerated to 100km/s, then synchronized with each other using Einstein synchronization. The clocks on rails are precisely accelerated and synchronized, so that they pass the stationary clocks at the same instant (as measured by the stationary clocks.) As the moving clocks pass the stationary clocks, each clock records its current time. If the experiment is a success, the stationary clocks will record the same time, the moving clocks will record a difference of approximately 1 microsecond.