[LEAPSECS] Schedule for success

Tony Finch dot at dotat.at
Thu Jan 1 00:57:41 EST 2009


On Tue, 30 Dec 2008, M. Warner Losh wrote:

>

> Time used to be strongly coupled to the earth.


Only because it was the most accurate clock we had. It might still be the
most reliable clock we have but our natural tendency to optimisation means
that isn't the most important consideration.


> Actually, the human race has been moving away from mean solar time for

> some time now. First the timezones decoupled man from local solar

> mean to a mean time around an arbitrary meridian. Next, daylight

> savings time has shown that we can shift that about by an hour and

> people cope. Finally, now that we can measure the second more

> accurately, we can see the slow drift.


Actually I would say that mean solar time was (past tense deliberate) was
a temporary aberration, lasting from mechanical clocks replacing the
sundial, to the rise of DST. Really, mean solar time only started to rule
our lives when we became industrialised and therefore ruled by the clock
rather than the sun, so I would date it to the establishment of railway
time: between the the 1840s in Britain and the development of timezones in
the 1870s in North America. The popularity of DST is because people prefer
to synch to sunrise instead of noon, and it wasn't long after the takeover
of mean solar time that the DST rebellion occurred, about 75 years.

Tony.
--
f.anthony.n.finch <dot at dotat.at> http://dotat.at/
PLYMOUTH BISCAY: EAST OR SOUTHEAST 5 TO 7, DECREASING 3 OR 4 IN SOUTH BISCAY.
MODERATE OR ROUGH. RAIN OR SHOWERS, BUT FAIR IN PLYMOUTH. MODERATE OR GOOD,
OCCASIONALLY POOR.


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