That’s just shifting the problem. There is no known way to reliably sync remote clocks except by sending packets and assuming the round-trip time is symmetrical. This is a known problem in physics: https://en.wikipedia.org/wiki/One-way_speed_of_light
Sure, but if we take it as true that light speed is the same in every direction – which is perfectly consistent with everything ever measured – you can measure speed between two endpoints using two atomic clocks and a synchronised experiment, with corrections for the relativistic effect of moving the clocks to the different places
That one is on your clocks quality, not on physics. People do it all the time.
Probably on equipment that is orders of magnitude more expensive than yours, but the post isn’t about costs.
Or use what PTP does.
https://en.m.wikipedia.org/wiki/Precision_Time_Protocol
Which is a more accurate protocol than NTP.
https://en.m.wikipedia.org/wiki/Network_Time_Protocol
That’s just shifting the problem. There is no known way to reliably sync remote clocks except by sending packets and assuming the round-trip time is symmetrical. This is a known problem in physics: https://en.wikipedia.org/wiki/One-way_speed_of_light
Sure, but if we take it as true that light speed is the same in every direction – which is perfectly consistent with everything ever measured – you can measure speed between two endpoints using two atomic clocks and a synchronised experiment, with corrections for the relativistic effect of moving the clocks to the different places