| [Updated: 04:26 12/02/2009] |
(see: Interspex, by Clark Nida)
Denizens of the Moon have no reason to keep to Earth-time, but every incentive to synchronise their calendar with the Sun. As on Earth, this passes across the constellations of the Zodiac, thus Seleneans can have lunar months named after the twelve sun-signs: aires, taurus, etc. The synodic lunar month is 708 h 44 min (SI-units). This conveniently permits a “month” of 4x7=28 “days” provided the “day” lasts 25 h, not 24 h.
The novel offers us the following definition of this odd, but curiously familiar time-standard:
Seltid, (ST) [Selensk: seltid = moon-time; from: sel- + tid = time]:
Selenean time-standard based on the lunar month (månad) of 28 circadians (dager) of 25 hours each. The månad always commences at sunrise on the zero meridian, which passes through Jordvik. This coincides with the Moon’s first-quarter as seen from Earth. The månad is divided into 4 uger of 7 dager, mostly bearing Danish day-names. The exception is måndag (Moon-day) which Seleneans would consider otiose, gaidag (Earth-day) being used instead.
Four intercalary periods, totalling 8 h 44 min averaged over time, are needed to synchronise the månad with the synodic lunar month. During these periods of forlorn tid ("lost time") the clocks stop. The four intercalaries are inserted before each søndag, commencing a minute after 24:59 on lørdag (the clocks stopping at 00:00). Three are of 2 hours duration. The fourth, ending the månad, is variable, finishing at sunrise as seen at Jordvik.
Note[1]: English speakers on the Moon use the Selensk names for Seltid time-units. This is to avoid confusion with the names of days, months, etc, in Universal Time ("Jordtid"), which may be analogous, but are quite different in synchrony and duration. Thus the start of the fatal eclipse: 4.42am, Tuesday 25 May 1975 (UT) was: 24:59, lørdag 14 taurus, 384 (ST).
Note[2]: Selensk, the language of Selene, is close enough to Danish as not to matter. Poul Anderson (in Tau-Zero) famously consigned the entire Earth into the care of Sweden. Accordingly Interspex has no qualms about handing the Moon to Denmark.