On February 30, 1712 in Ystad, Sweden, Ellna Jepp sdotter married Sven Hall. Because Sweden added that extra day just once, Ellna and Sven could never again celebrate on February 30th. Sweden had also added February 29th that year because her calendars were not in sync with other places.
Where are we going? To how time, like weights and measures, is a unit that we have to standardize.
But first, some background and a little history.
Clock Time or Solar Time?
Based on how long it takes the earth to rotate around the sun, a year is really 365.242 days. Then, it gets even more complicated because friction is slowing the earth’s rotation on its axis. Although the world’s clocks that use Coordinated Universal Time say a day is 86,400 seconds, we are constantly adding milliseconds. The result? As those extra seconds add up, our clocks become less coordinated with sunrise and sunset.
Clock Time or Local Time?
During the 19th century in the U.S., one end of a New England town could have a different time from the other side. Keeping a lunch date, telling when something happened in a newspaper article and punctually meeting a train were potentially challenging. Still though, liking their local power, towns resisted uniformity. It was the railroad that made universal time a necessity. Faced with 70 time zones, by 1883, railroads had whittled them down to four. In 1918, the Congress agreed.
You can see that time uniformity creates many dilemmas. We have the difference between clock time and solar time that needs to be reconciled. And, with some people suggesting we need just one for the world, time zones remain an issue.
The Leap Second Solution
Although not everyone agrees, for now, we solve the clock/solar gap with leap seconds. On June 30, the last minute of the day will have 61 seconds. Below you can see when we have enjoyed extra long days during the past 45 years.
Our Bottom Line: Standardization
Somewhat invisible, synchronized time is a human creation and a commercial necessity. Producing externalities that benefit and harm third parties, standardized time influences how easily businesses in the same town and around the globe can coordinate, it relates to airline reservation systems, and it facilitates consistent programming for our satellites and home video systems.
And it takes us back to Sven and Ellna’s deleted wedding date.
