[LEAPSECS] Does the "leap second" matter?

Rob Seaman seaman at noao.edu
Wed Aug 7 19:07:56 EDT 2013

Hi Kevin,

> I have to admit that the idea of biological clocks makes me cringe a bit.

> This is because "clock" is a metaphor that is constraining biological and

> neuroscientific research right now.

We traded some email earlier and I don't disagree with anything said. I might assert that "clock" is just as misleading a metaphor in the physical sciences :-)

> Biological systems are not clocks. If they were good clocks, we'd have no

> need for clocks.

Something like http://youtu.be/q030WNZvXrA

...and it's decimal!

> Instead, the circadian cycles that Dava talks about and

> which Cziesler has done extensive research on are systems that are very

> good at maintaining themselves for durations on the order of a few days,

> but they need a time time reference to continue to function properly. In

> most species, the time reference is exposure to light (particularly

> sunrise). Without the time reference, the cycles drift.

Just as with the 10,000-year clock:


> As a result, time in biological systems is different from a continuous

> timescale since the biological systems are designed to reset every day

Distribution of a "continuous" timescale depends on the same requirements:

"...an electronic timekeeping protocol needs some wiggle room to adjust the rate of each clock to maintain nominal time agreement with the national timescale." - D. Mills, Computer Network Time Synchronization, p.2

Just a matter of the size of the wiggles :-)


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