Leap Seconds

by Elaine Schwartz    •    Jan 6, 2012    •    682 Views

The earth is supposed to rotate every 24 hours. Sometimes, though, it takes less time and sometimes it takes more. So, to be precise, we depend on atomic clocks.

And therein lies the problem. 

Increasingly, Solar Time (earth rotation time) deviates from TAI (atomic clock time or Temps Atomique International). According to Wired, if we let them remain out of sync, “after several hundred years we could be eating lunch in the middle of the night.”

The solution is the leap second. On June 30, 2012, at one second before midnight, an extra second will be added before we get to July 1. Planes will delay landing, computers and phones will have to adjust.

Synchronizing time is a modern phenomenon. Traveling from town to town during the 1830s meant constantly changing your watch (if you had one). By the 1850s, though, local time started becoming railroad time.

Keeping Watch: A History of Time has a wonderful story about the railroad. The invention of the telegraph enabled the same time to be communicated from place to place. As a result, railroads gave conductors, engine drivers, switch tenders and bridge tenders “a good watch.” The conductor was responsible for coordinating the watches before each departure and making sure that stations along his route had the same time.

Once the stations had the time, so too would the town. After all, if you were picking someone up at the station or your supplies were arriving by train, you had to know the time. Local time? No. The railroad’s time.

Our bottom line: Synchronized time was crucial for economic progress.

The Economic Lesson

In a 1790 report to Congress, Thomas Jefferson submitted his “Plan For Establishing Uniformity in the Coinage, Weights, and Measures of the United States.” Continuing the principle that the federal government is responsible for uniformity, the National Bureau of Standards, now known as the National Institute of Standards and Technology (NIST) was established in 1901. For the official time, we look to NIST.

An Economic Question: Explain why you agree or disagree that as travel time and communication time diminished, synchronizing time had to become more and more precise.

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