Poul-Henning Kamp wrote:
> Clocks do simulating anything, there is nothing for them to simulate.
Aside: A nice example of the system engineering process. You are rejecting
the assertion of a requirement. Note that we aren't led into back alleys of
fretting about one particular solution versus another. Rather we can debate
the requirement by itself.
To continue the debate:
Balderdash! Of course clocks simulate some external process. You argue this
yourself:
"The goal of all metrology, is to use fundamental concepts that allows
measurements to be reliably reproduced anywhere, any time, independently."
You are asserting that clocks should in the future simulate other "fundamental
concepts", that's all. Does your wristwatch actually function using those
concepts? No - it simulates them. We don't differ on the question of
"simulation", we differ about what is required to be simulated.
You are attempting to assert that no requirement exists to tie the zero point
or rate of UTC to macroscopically visible shared phenomena:
> Seconds have been liberated from their earthly toil, and there is absolutely
> no reason to confuse them with earth rotatation angle anymore:
And yet the ITU isn't seeking this liberation. They are tied very closely to
mimicking a mean solar time scale. I am merely asserting that their limp
proposal is not nearly close enough. You are asserting it is. This is very
different than claiming the freedom to "liberate" the clocks entirely. The ITU
proposal is not - cannot be - to mistune length-of-day by even as little as one
part in one hundred-thousand. The ITU proposal is not - cannot be - to shift
the phase by a jump of even minutes, let alone hours. Mistune from what? From
the synodic day.
Those limitations on the ITU proposal are the result of underlying system
requirements. In particular of a requirement that "day" means "synodic day".
There is an additional requirement that clocks simulate a cadence corresponding
to the SI-second. These are two separate requirements and any proposed
solutions have to engage in trade-offs of one sort or another.
The ITU are the ones confusing SI-seconds with synodic days. They represent
two different clocks.
> Ever since Harrisson we have been able to keep time without telescopes.
Er - no. Chronometers were set via Greenwich observations prior to setting
sail.
Rob
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