On 1 May 2014 at 18:51, 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, as agricultural rhythms will conform to the local seasonal
> cycles. 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, so that the Martian
> day would be 24 *hours of 60 *minutes of 60 *seconds, so that everything
> comes out nice and even, and time-zone corrections don't have to worry
> about "are they six hours ahead or are they in Comp right now, or ...".
> For communication with Earth, I'd have access to clocks and calendars
> that keep Earth time, but it doesn't otherwise make sense for Mars to
> conform to an Earth clock or Earth calendar - it simply doesn't fit the
> astronomical facts of Mars.

Changing the length of the second (and even, minute hour and day)
will *really* mess up all sorts of technical stuff. Time units
(usually, but not always seconds) are an integral part of far too
many units.

Watts use seconds. Velocities are in km/s or km/hr. using a diffeent
value for the second or hour is *asking* for trouble.

But we already have the precedent of calling Mars' local solar day
the "sol". So local "days" are "sols", with "day reserved for the
period of 24 standard hours.

Dividing the sol into subunits can be done all sorts of ways. There
are good arguments for dividing into 12 or 24 parts as it makes
setting shifts and such much easier. But some folks will go for
decimal time, in which case you have decisols, centisols and
millisols.

On Mars a decisol would be 887.5424409 seconds or around 2.5 hours.
A centisol would be 887.7524409 seconds or about 14.8 minutes.
A millisol would be 88.77524409 seconds or about 1.5 minutes.

Using "duras" for subdivisions of a day (like David Brin did in some
of the uplift books), if there were 24 duras to the Martian sol, a
dura would be 3698.96850375 seconds, or about 1.03 hours. A decidura
would about 6.16 minutes. A centidura would be about 37 seconds.

Let's pick a different unit. Say the "peri" (from "period"). At 12
peris to the sol, Mars would have a peri that was about 2.05 hours. A
deciperi would be about 74 seconds.

Other worlds may have all sorts on names for the subdivisions of the
sol. And may use divisions of *those* other than decimal.

Longer periods? Well, Earyth has had "weeks" that are lengths other
than 7 days. And in various calendars the length of the montyh varies
from 19 days (Ba'hai calendar) to various 27, 28, 29, 30 and 31 day
mixes.

So month can be fairly variable without causing a lot of confusion.

Year is the next place that will vcause confusion. Might be good to
come up with a separate term for "local year". Anno might be good,
except that's way too close to something else in most Romance (Latin-
derived) languages.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com