Measuring time in months and years

EE-Evaluation Engineering readers are likely to measure time in units of microseconds or picoseconds, yet time measurements in terms of months and years have presented challenges for millennia.

Farah Stockman presents a concise history of timekeeping on the month and year level in the Boston Globe. She quotes Denis Feeney, author of Ceasar’s Calendar: Ancient Time and the Beginnings of History, as saying, “Every society attempts to track time. Even the first societies discovered in the middle of Papua New Guinea know when to plant and when to harvest. No one just drifts through time, not even hunter-gatherers.”

The reason for New Years Day falling on January 1 seems to be a bit of a mystery. “Early American colonists,” Stockman writes, “celebrated New Year’s Day on March 25, until the date was officially changed in 1752.”

Writing in Slate, Phil Plait adds, “Not surprisingly, there was a lot of religious influence on when to start the new year; for a long time a lot of countries used March 25 as the start of the new year, calling it Lady Day, based on the assumed date when the archangel Gabriel told Mary she would be the mother of God.”

The ancient Romans seem to be among the first—at around 153 BC—to begin the new year in January; they, too, like the American colonists, had celebrated it in March. The reason for the change remains a mystery, Stockman writes.

Of course the Romans had bigger timekeeping challenges than on what day to begin the new year. As Stockman notes, their 354-day year, with months tracking the moon, got out of synch with the seasons, requiring that chief priests insert a few days every couple of years.

That became a problem when Caesar “spent a decade fighting wars in distant lands,” Stockman writes. “He couldn’t add days to the calendar while he was away.” Apparently this was a task that couldn't be delegated. Consequently, “Time grew increasingly out of whack. The month of March, which everyone knew to be spring, began appearing mid-winter, as snow fell.”

An Egyptian astronomer suggested a solution—a solar calendar of 365 days, with an extra day in February every four years. The Julian calendar took effect in 45 BC, after a 445-day-long realignment year in 46 BC—required for synchronization.

The Julian calendar worked well for a while, but because a year is not exactly 365.25 days long, extra days began to pile up—about three days every four centuries. In 1582 Pope Gregory added a 0.002% tweak in the length of the year to compensate, giving us what is now internationally the most widely accepted and used civil calendar.

Are we finished tweaking the calendar? Modern-day Caesar Matthew Yglesias, writing in Slate, proposes a calendar based on the Republican calendar adopted during the French Revolution. The current calendar, he writes, is broken because months have different numbers of days and months do not contain integer multiples of weeks.

Yglesias would retain the current 12 months, but each would include three 10-day weeks. The year would end with a five-day holiday (six days in leap years).

Why do this? Says Yglesias, “Best of all, instead of a week consisting of five workdays and two weekend days, it will consist of seven workdays and three weekend days. Having 30% of the week be weekend time rather than the current 28.5% of the week has two major advantages. One is that you can maintain a constant number of hours of work per week by slightly extending the workday, which would still result in less commuting and therefore less pollution and less wasted time. The other is that it will smooth the transition to an era of higher productivity and less working.”

Interesting, but there are drawbacks. Yglesias doesn't address Pope Gregory's 0.002% correction, so he needs to go back to the drawing board. Readers commenting on Yglesias's article cite their own concerns. One doesn’t want to work seven days straight.

Siva Prasad suggests a 13-month calendar with four seven-day weeks per month—that would require only one universal end-of-year holiday (two during leap years). “And while we are it,” Prasad writes, “why not redefine the second so that there are 100,000 seconds in a day instead of 86,400 and divide them into 10 hours each with 100 minutes and each minute with 100 seconds.”

Any such scheme would add complications. Korrektus notes, “That would be the greatest bonanza for computer programmers ever. It would make the surge of work done for Y2K look like a microscopic occurrence. Think of the number of user interfaces to rewrite: any type of date input, from simple text fields where you type in the numbers of the day, month, and year, to drop-down selections, to pop-up calendars.”

It's an interesting concept, but I don't think the Yglesias calendar is going anywhere. Aside from the implementation difficulties, it solves a problem that doesn't exist, except for young children who haven't learned the knuckle rule.

Stockman in the Globe concludes her column by advising “… take a moment to consider the miracle of collective human experience across the ages. The fact that billions around the world take [January 1] to be the first day of something new is nothing short of astonishing.”

Happy New Year!

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