On Thu, May 01, 2014 at 06:51:18PM -0400, Freelance Traveller wrote:
> Where the local astronomical year doesn't match up with the Imperial
> year, a local calendar may be considered more important than the
> Imperial one

Yes, and that's going to be true essentially everywhere.  The chance
of any planet having exactly the same day and year length as any
particular standard will be negligible.  Even with the possibility of
mega-engineering projects, the energy of rotation for a whole planet
is astronomical.  (Much more so for altering the orbit)

> Local timekeeping may persist, too, as a better fit than the
> Standard Imperial Clock - for example, rather than adding a 37-odd
> minute "comp" to the day if I were on a resource-independent Mars,
> I'd simply make my seconds about three percent longer

The problem there is that seconds are a fundamental unit used in a lot
more than just human clocks and calendars.  Adjust Martian hours or
minutes if you like (and live with the unintended consequences), but
altering seconds would be a horribly bad idea.  Alternatively, at the
very least call them something totally different and impossible to
confuse with seconds.

Of course, Mars is a remarkable case in being so close to Earth in
average day length.  Most planets should have very different day
lengths, e.g. between 8 hours and hundreds of Earth days.  Year
lengths will mostly depend upon the class of star they orbit, about 20
to 2000 days with most habitable worlds likely having shorter year
than Earth's.

So yes: the Imperial Calendar will generally have no relation whatever
to local planetary time periods.

As a counterpoint: most planets will have little relation to human
sleep/wake cycles, while the standard calendar will be pretty close.
I think I could make a case that people in a technological society
(with artificial lighting and housing) could adapt much more easily to
being out of sync with local day and night, than to sleeping on an
83-hour local cycle.

Similarly for years.  A lot of planets aren't going to have
significant seasons anyway, and of the rest many won't be shirt-sleeve
habitable enough for it to make a difference (check a lot of those
UWPs!)  Some jobs may need to take local seasons into account, but
nowhere near as many as on ancient Earth, and the seasons are still
easily predictable in advance without having to line each of their
days up with the same local label.

So perhaps the standard calendar would see local applicability on a
wider range of planets than first thought might indicate.

- Tim