Engines of Our Ingenuity

No. 1073:
A NEW YEAR

by John H. Lienhard

Click here for audio of Episode 1073.

Today, a young boy plans to see the Third Millennium. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

January 1, 1996: This is a special New Year's day. When I was a boy, I decided I'd live to see the Third Millennium. My grandparents had all made it to ages which, if I could match them, would get me past the year AD 2000. Still, life is uncertain, and WW-II was making it clear just how uncertain it could be.

By the time I was 17, I'd found an American Experience Table of Mortalities. According to it, I had only a fifty percent chance of making it even to 1996. Now, having come that far, my chances of reaching the year AD 2000 are better than 80 percent.

But there's an odd catch to all this. It has to do with calendars. Calendars are complex. My encyclopaedia devotes 17 double-column pages to them. The problem starts with the moon.

It takes sophisticated astronomy to mark the repetition of the year. Meanwhile, the moon exhibits a very clear 28-day cycle. That lunar period is slightly out of synch with the year, but it's a powerful cycle. The Latin word for months, menses, signals how strongly the moon is tied to the human body.

The ancient Romans based their year on 12 lunar cycles. They further muddied that with politics -- stretching or compressing the year to fit magistrates' terms of office.

Julius Caesar finally mandated calendar reform in 48 BC. In his Julian calendar, three 365-day years are followed by a 366-day leap year. But that calendar was still 11 minutes off. It gained three days every 400 years. In 1582 Pope Gregory mandated a new calendar that omitted leap years every century or so.

Gregory also had to correct the error that'd accumulated over the centuries. So he moved the Feast of St. Francis on October 5th to October 15th. He simply erased ten days from 1582. That adjustment has confused Renaissance historians ever since.

We live by the Gregorian calendar today, but we have to insert seconds to make up for its minor inaccuracies, and to make up for the fact that earth's rotation is slowing very slightly.

Now, back to the matter of the Third Millennium. With all the confusion of the old Roman calendar, it's hard to date the birth of Christ. When was zero BC*? We know Christ was born during the reign of King Herod, who died in 4 BC. We also know the Roman census that called Mary and Joseph to Bethlehem was announced in 6 BC (by the inaccurate Roman calendar). Our best bet is that Christ was born in 4 BC or shortly before.

So this new year cleanly places me in the Third Millennium -- beyond the actual 2000th year AD. I got here ahead of schedule! 1996 has to be a good year, by my reckoning. I've lived as long as I'd set out to. And the rest? Well, now it's pure gravy.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


My source on the calendar matters here was the 1970 Encyclopaedia Britannica.

* Our calendars, of course, don't really include zero BC. The year 1 BC is followed by 1 AD. That is a matter I chose not to tangle with in this episode.

I wrote this episode for New Years Day, 1996. In July 2010, Lis Perez provided this web page with a nice summary of the history of he Western Calendar.


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The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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