Waiting for the kalends
How you tell time tells something about you.
This post will appear, if all goes as scheduled, on Tuesday the 26th of December 2017. This current way of designating a date seems convenient: the day of the week is important for some things; the day of the month allows us to count a few days forward or back. The month is a larger chunk of time, still useful even for those people who don’t notice the cycle of the Moon (from which our calendar has become detached in any case). The year is added when we think in even longer time spans.
But it’s not the only way to tell dates. In Europe the traditional method was to navigate time by saints’ days and the feasts of the Church. This post should appear on the Feast of St. Stephen, which is in the season of Christmas. A particular day could be specified through a saint (if necessary a day or two before or after), while a season talked of a longer period: “Much rain and wind this Pentecost, as none can remember before.” This system makes sense for people whose activities revolve around the Church, as the stable institution in their lives and the organizer of time. Reigns of kings or dukes are more local–and much harder to time sowing and reaping by.
In parallel to this and much older is the Roman calendar, instituted in the legendary past of Rome and still used by some people (mostly the Church and chroniclers) up through the Reformation. Each month has three days of importance, seen as particularly unlucky: the kalends, the beginning day; the nones, the fifth of some months and the seventh of others; and the ides, the thirteenth of some months and the fifteenth of others. Other days are designated by counting down, inclusively: the day before the ides is the second of the ides, the day before that the third.
So as a Roman you are perpetually on the watch for bad luck, warily keeping track of how long until it might arrive. One can speculate that this fits the Roman character. It was the practice of the legions, after all, to march twenty miles or so until mid-afternoon, then build a fortified camp in which to spend the night even when there wasn’t an enemy in sight. The Roman army won many campaigns simply by being careful and not losing battles, rather than by employing flashy tactical devices.
Scientists of course need to keep track of time. But a calendar of Church seasons of variable length, changing from year to year with the date of Easter, is difficult to count with. Even months of different lengths are annoying, and combining days with months and years is messy. So astronomers employ something called the Julian Date: a single number denoting the number of days since January 1, 4713 BC. Putting the beginning so long ago means rarely having to use a negative number (our astronomer notes that even simple addition and subtraction can pose problems by 4am, if you’ve been observing all night), and only keeping track of days means you can ignore things like variable months and Leap Years. You can talk of smaller units of time by using decimals, for instance saying the observation was conducted at JD 24508065.2315.
Of course this means you need to have a conversion table on your computer, and the full JD is a big number. But astronomers have computers and are comfortable with big numbers. As the Romans were careful and forward-thinking, and Medieval peasants worked around the feasts of the Church. What does your way of telling time say about you?
