[Plutoberth]

I don't understand. Wouldn't it only be possible to find out by comparing two identical clocks that were at different altitudes for some larger number of ticks, allowing you to then compare the elapsed ticks? How would you conduct such an experiment? My mental model is that I have a black box that outputs an electrical signal every tick, and then maybe we could just figure out which clock ticked first with a simple circuit. But that seems like we would need to sync them, and that it's fundamentally wrong due to the fact that the information of the tick is also subject to the speed of light. I don't know much beyond high school physics, fwiw.

[rcxdude]

My comment here might give some intuition for it: https://news.ycombinator.com/item?id=44576004 . You do need to measure for some time, because the measurement of the clocks with respect to each other is noisy, but you don't need to wait for there to be a whole 'tick' of extra time between them.