Wednesday, January 16, 2013

Swords of Mars: The Martian Calendar

Martian days are only slightly longer than an Earth day (less than 3% longer), but the Martian year lasts about 670 days. Mars’ eccentric orbit means its seasons are not equal in length -- the Martian Spring lasts 210 days, Summer 180 days, Fall 160 days, and Winter, 120 days.

Months mean nothing to Martians — Mars’ two moons, Phobos and Deimos are small, dim, and fast–moving. Phobos orbits the planet every 8 hours, Deimos every day. Both moons are tidally locked, and thus do not have phases to track — they always look like bright stars or planets in the sky rather than like Earth’s moon. Martians track the calendar by season, using equinoxes and solstices to track the start and end of each season. Martians just track the number of days in the season, so they may note that a day is Winter 111.

Martian years were numbered by the name of the ruler, and the year of their rule. Once, the ruler was the ruler of the great Kingdoms that dominated Mars. Now, the ruler tends to be more local. This means that cross-referencing year references from place to place on Mars can be a challenge for Terran scholars and bureaucrats, and that the notations can lead to confusion and miscommunication, but Martian society currently lacks a strong unified way of keeping track of the passage of the year.

Martian time-keeping is very local, and while clocks exist, Martians lack a common system of relating time from location to location.