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Annus Martis

© Robert Davis

Well, it's a new year (should I have capitalized that?), and of course it wasn't but a week ago that we celebrated Christmas, so that's two holidays on the brain. Moreover, since I used to live in England, I invariably observe Boxing Day on December 26th but nobody except the occasional Canadian seems to know what I mean. I suggest that we Americans formalize the after-Christmas sales as our observation of Boxing Day, but for the sake of all the postmen and milkmen (although here in the States I don't know of any remaining milkmen) and garbage men and the like, I'll just go ahead and explain that on Boxing Day, you're supposed to give a little something to those folks whose services are so crucial to you from day to day. Point is, it's been that time of year that we so euphemistically refer to as "The Holidays", and so I've had calendar dates on the brain for awhile now. And having calendar dates on the brain got me to thinking about holidays on Mars.

Birthdays and anniversaries and holidays and so on are annual events. But for the settlers of Mars, the Earth year to which we are accustomed is just somewhat more than half the Martian year. This poses an interesting problem.

In the early days, I imagine people will stick pretty closely to the Earth calendar. Writing a computer program to calculate Mars dates from Earth dates isn't all that hard; I did it myself in short order. Consequently, the settlers of Mars will be able to say, "Okay, when is Christmas this year?" Of course, more often than not there will be multiple Christmases in a Martian year, but that's not really the issue. The point is that there's nothing altogether untoward about calculating dates and marking the calendar accordingly. In fact, we do it ourselves; Easter and Thanksgiving and probably more special occasions than that are not on the same day every year, after all. What is more, there is a fifteen-year cycle of coincidence between the years of Mars and Earth. What that means is that if your birthday falls on Virgo 29 this year, in fifteen years (those are Earth years) it will fall on Virgo 29 again. On Mars there could very well turn out to be a market for comprehensive fifteen-year calendars! (Well, they'd be something like eight-year calendars, but they'd have fifteen years' worth of Earth dates covered.)

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