I'm reading a book on Time. The interested came about after reading a book on life in England in the year 1000. Life back then didn't have clocks. The church didn't have a tower with time - those arrived in the 1300's. Days were marked by sunrise, noon and sunset. There were sun-dials that created hours as divisions of the day that changed as the seasons changed. In the summer, hours were longer, in the winter, they were shorter. If one woke in the dark, s/he had no way of knowing if dawn were almost there or if they had been sleeping for merely an hour. I find it nearly unfathomable.
My first thought, "How could two people meet for lunch?" and then I realized, there were no restaurants, so meeting for lunch wasn't going to be a concern. Hmm, life existed before lunch dates?
Speaking of noon, we have standardized noon. Before we divided the world into time zones, every town had noon on their own - why not? Was noon anything other than when the sun was highest overhead? Yet, as we now are divided, from Las Vegas to San Francisco our watches read 12:00 and the sun may not be at its highest point over head. We switched from sun time to clock time.
Clock time marks our days, for those of us raised in the digital age, imaging all towns setting the clock over their town hall to be noon at the local, sun-time of noon seems absurd. Yet, as recently as 75 years ago, that was the way it worked. The trains were the stimulus for the change to time zones. Think, if a train was leaving San Francisco at 12 noon and had a 10 hour journey to Las Vegas, when would it arrive? How would the stations along the way - each with their individual setting of the hour know when the train should arrive? Say the train reached Fresno after 4 hours - would it be 4 PM or something possibly later (as Fresno is father east, it would, presumably, have time running slightly ahead of San Francisco).
Only in the first quarter of the last century did people start to wear watches. This came about during WWI - as soldiers were issued wristwatches so that they might better sync up. Along with watches came migration and movement... the trains would have the say. They divided up the country so that they could make arrival and departure schedules. The time of sun defined noon came to a close.
It would be only a matter of years before the move from sun-time to clock-time was complete. Think, man started to mark the days with the sun dial - giving days divisions: night, before noon, noon and afternoon with changing hours. Then the clock was invented - a means to produce a regular marking of time developed in the 1300's and then hours were no longer divisions of the day, but independent. They were X-number of clicks of the clock. The day soon was divided into 24 equal hours - no longer 12 hours for the time when the sun was up & 12 hours of darkness. Now the hours were independent from the days. As the clocks progressed we got minutes - in the 1600's there were 4 divisions in the hour. But 1800 there were 60 minutes in the hour. By 1900, there could be 60 seconds within the minute. As our clocks developed, so did our divisions of time. Yet until 1967, the second was a division of a day: 1/86,400 (60 sec x 60 min x 24 hours).
In 1967 the second changed. From a part of a day, it was modified to a definition I can't quite understand:
"Since 1967, the International System of Units has defined the second as the duration of 9,192,631,770 cycles of radiation corresponding to the transition between two energy levels of the ground state of the caesium-133 atom. This definition makes the caesium oscillator (often called an atomic clock) the primary standard for time and frequency measurements."
Thank you Wikipedia.
Evidently, we cannot trust our second as a division of day, as the earth's day isn't quite the same. At some points in the trek around the sun, we spin faster or slower. Who knew?
Seeing the history of the hour, I realize how arbitrary my watch is. A part of me longs to return to the time we woke when the sun rose and retired as it set. Hard for many to understand me saying that, with my history of all-night parties, I know. But noon should be when the sun is highest. Sunrise should start the day. Why complain about the change in time from day light savings? The sun still comes up regardless of whether we call it 6 am or 7.
Not that I believe we could run our nuclear lives on solar settings.