Moon Miners' Manifesto

#7 July 1987

Essays in "M"

M FOR MONTH, OR SUNTH:

Originally, of course, the term month meant the span of a full set of four phases of the Moon, e.g. from full moon to full moon, or from new moon to new moon, terms which render the appearance of the Moon to the inhabitants of Earth. On the Moon itself, this lunar month of 29.53 Earth days would rather appear to denote a full set of phases of Earth, e.g. full earth to full earth, except that this definition of month would seem irrelevant to anyone living on the Farside from which Earth was never visible. Rather, to the Lunar Settlers, this period, called a lunation by our astronomers, will simply signify the period from sunrise to sunrise or sunset to sunset on their world. Accordingly, they might well prefer to call it simply the "sunth", especially since this term is less stuffy than "lunation" and avoids confusion with Earth's calendar months of Roman origin which do not coincide at all since they average about a day longer in order to divide the year into twelve with no leftover. The Sunth then would be the natural way of reckoning the passage of time on the Moon.

M IS FOR MERIDIAN:

The Replogle globes of Earth and Moon alike are divided into 15 degree longitudinal segments. For the Earth, this is a natural, since 15 degrees is the width of the idealized time zone ( 15 * 24 = 360 ). On the Moon, however, the slow daily crawl of the terminator line dividing sunshine from darkness is 12 degrees (12deg, 11min, 27sec). So for the purposes of settlers of the Moon or for people on Earth who want better to comprehend what life on the Moon would be like, Moon Globes should display meridians marked every 12 degrees. A Lunan student could then easily estimate by how many dates the sunth is retarded or advanced in his location as compared to other sites on the Moon.

M IS FOR METONIC PERIOD:

A 5th Century B.C. Athenian by the name of Meton noticed that the Moon's phases returned to the same dates of the year after 19 years ( i.e. 228 calendar months = 235 lunar months ). The Metonic period is important for anyone who would devise a calendar which respected the 29.53 day lunar month or sunth, and yet reconcile it with Earth's 365.25 day year at least periodically.

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