So at the end of the day it doesn't matter if it's in 'error' or a fundamental to the physics even under perfect conditions. Neither are really under your control and both have the same answer.
> You can't escape answering the question: do I care about the time elapsed at home or the time elapsed here?
We already have that concept, in the difference between CLOCK_WALL and CLOCK_MONOTONIC. You use monotonic for "local temporal reference frame" and wall for "proxy of globally visible temporal reference frame". Wall shifts around anyway as NTP or what have you figures out how skewed off of "actual" time you are.
Yes you can. When error swamps the difference between two things, you don't have to choose.
Do you set your analog alarm clock to wake you at 6:00:00 or 6:00:05?
Anyone on Earth can just say their computer clocks are set to "Earth", ignore relativity, and use their normal clock skew correction algorithms.
It's not "You can't escape answering the question". It's "Interplanetary spacemen can't escape answering the question." And those spacemen might not even use seconds.
We should also define the length of a second to mean "at sea level in Greenwich".
The quest to eliminate irreproducibility from metrication is why SI did all that work to finally eliminate the kilogram prototype. The second was defined reproducibly decades ago because trying to define it based on our planet's inconstant spin was such a failure.
The fact that the Earth's spin is not constant is perhaps frustrating, but like other facts just insisting it isn't true doesn't help you.
But the size of the discrepancy between Colorado and London is far smaller than the discrepancy Leap Seconds are concerned with right?
Why would it? My redefinition just means the length of a second is defined as a given number of cycles of caesium in a gravitational field equivalent to that of Greenwich.
If you're in a different gravitational field, you'll just have to convert the values easily.
That's why I proposed changing the second definition to 9192631770 cycles in a gravitational field equivalent to that of Greenwich.
> Tidal datums must be updated at least every 20-25 years due to global sea level rise. Some stations are more frequently updated due to high relative sea level trends.
If we are going so far as to rigidly include "sea level" in the definition of "a second", it would probably help if we say that that we mean mean sea level.
Know what I mean?