The universe appears "old", but it is still less than 10,000 years old

[Anomalocaris]

If you only use one clock to compare the time of arrival of the signals through the cable, then any conclusion you draw about when the signal originated at the other end of the cable must implicitly assume the signals to have traveling through the cable moves at the known speed through the cable regardless of the paths and orientation of the direction, ie isotropically.

But to validate the signal actually travelled isotropically, you would need another clock at the other end of each cable. Hence the need to synchronize clocks over distance.

So if you actually remove the assumption that signals travel isotropically from every stage of your experiment, you would eventually end up with an untestable clock synchronization assumption.



Regardless of your assumption, I think your experiment is a good one, because your assumption is an absolute minimal one, and all other assumptions are equally untestable, but all are more elaborate, and therefore contrived.

This is why your assumption is not a problem for me.

I raised the point because you brought up the time dilation issue. I wanted to point out lack of time dilation does not remove the fundamental assumption. But the experiment is convincing even with the fundamental assumption,