Rob Seaman said:
>> As I've said before, eventually the notion that the solar day contains
>> 24h of 60m of 60s will have to be abandoned. It'll be awfully hard
>> to maintain when an "hour" involves two human sleep-wake cycles,
>> out in the limit when the Moon is fully tidally locked and 1 lunar
>> month = 1 solar day = 47 current solar days, more or less.
> Just returned from a conference three hours to the east. The
> existence of
> jet lag suggests significant evolutionary pressure locking human sleep
> cycles to the length of the day.
Actually, the evidence from experiments is that the "natural" sleep-wake
cycle is about 27 hours long, but force-locked to the day-night cycle (it's
easier to synchronise a longer free-running timer to a shorter external
signal than vice-versa). So humans will cope until the solar day is about
27 (present) hours long, after which we'll probably start to move to a
system of two sleep-wake cycles per day.
--
Clive D.W. Feather | Work: <clive_at_demon.net> | Tel: +44 20 8495 6138
Internet Expert | Home: <clive_at_davros.org> | Fax: +44 870 051 9937
Demon Internet | WWW: http://www.davros.org | Mobile: +44 7973 377646
THUS plc | |
Received on Wed Jun 07 2006 - 02:02:00 PDT