On Sundials, Timepieces, and Standardized Time

Don't forget! This year, daylight saving time comes early as we'll make the change overnight March 10th/11th rather than the first weekend in April.

Fortunately, nobody has yet talked about replicating the infamous Daylight Saving Time Energy Conservation Act. In 1974, the clocks remained on daylight saving time through the dead of winter. Ironically, folks ended up burning every light in the house each morning while getting ready for work and school due to the extended darkness!

That aside....the time change got me thinking about the concept of time as New Testament people knew it.

With Holy Week approaching, we'll of course hear and read references to Christ's crucifixion at the third hour. When is the third hour, anyway? In ancient Rome, the day was divided into two periods: day, which began roughly at 6am and continued until 6pm, and night - the other 12 hours. Ante meridiem (before midday) and post meridiem (after midday) are terms still in use today - we abbreviate them as AM and PM.

With the day beginning at 6am, that makes the hour that Christ was crucified, the third hour, 9am. Darkness descended upon the earth from the 6th until the 9th hours, or from noon until 3pm.

How did people of that period know the correct time of day? They used sundials. You'll even find a sundial mentioned in the Bible, in reference to a miraculous sign from God. You can read about it in 2 Kings 20:1-11.

Sundials measure time as it is in a specific location. As the position of the sun changes during the course of the day, the post in the center of the sundial casts a shadow on a circular plate. Marks on the plate indicate the correct local solar time.

That means your friend's sundial in the next town will read differently than yours at the same exact moment, because the sun is in a slightly different position at his location than it is at yours.

As late as the mid- to latter part of the 19th century, sundials were still in widespread use; mechanical timepieces such as watches and clocks were set to sundials.

Railroads and the advent of mass communication (the telegraph) were the impetus for the standardization of time - and the demise of the sundial. Standardized time made it possible to coordinate train schedules and paved the way for technical and commercial progress.

"Clock time," unlike sundial time, is an artificial - but uniform - measurement, assuming each day to be exactly 24 hours long, with consistency across time zones.

There's been a bit of a renaissance in sundialing, though, with sundial societies having sprung up across the globe. For example, the North American Sundial Society, founded in 1994, is comprised of folks from all walks of life who are interested in the study, development and preservation of sundials. As they point out, "there was a time, not that long ago, when an appreciation of dials in all their various forms was an integral part of the scientific and mathematical training of any well-educated person."

Interested in building your own sundial? It can get a little complicated, but the link below features instructions that are fairly straightforward and don't require an advanced degree in mathematics!

If you're game, try making your own accurate timepiece: http://liftoff.msfc.nasa.gov/Academy/Earth/Sundial/Sundial-ConstructSimple.html