If you are as I am, among those who think the people responsible for Daylight Saving Time, while not necessarily evil, are at least deluded…then let’s talk about clocks and time.
One of the arguments I hear when I engage in my semi-annual rant against DST is this: “It’s all just arbitrary anyway. What does it matter?” Granted, hours and clocks are human inventions, but they are inextricably tied to astronomical cycles. A day is the time that our planet takes to turn once on its axis. A year is the time Earth takes to travel once around the sun. Noon is the middle of the day, at least when we are on standard time. Sort of. Let’s take a closer look.
For those of us in the northern mid-latitudes (Lynchburg is at 37.4° N), the sun is nearly always in the southern part of the sky. It travels from east to west during the day, from our left to our right as we face the south. When it reaches its highest altitude, it is directly south. This is local noon.
But here’s the thing. Shift your position just a few miles east or west and that time will be different. At Lynchburg’s latitude, go a little over 50 miles east or west, and there will be a four minute difference in the time of local noon.
In times before long-distance travel and communication, this didn’t really present a problem. Each settlement kept its own time by a sundial, and no one really concerned themselves with such fine divisions of time as whether it was 9:32:28–roughly half past nine o’clock was close enough. It was the advent of railroads, first in Britain and then in the U.S., that brought about the need for some standard of time. Even so, it was not until 1918 that the current system of time zones was set by law in the U.S. Clock time is the same throughout a time zone, and each time zone is centered on a longitude where solar time is the same as that zone’s clock time.
The Eastern Time Zone in which Lynchburg lies is centered at 75 degrees west longitude, five time zones west of the prime meridian, the 0° longitude line that runs north and south through Greenwich, England.
Lynchburg’s longitude is a little more than 79° west, so our local noon is a few minutes later than 12:00 (or 1:00 when DST is in effect). We’re not that far from the center of the Eastern Time Zone, so the difference is not large. At the boundary between one time zone and another, the difference can jump from clock time being significantly earlier than solar time to being significantly later.
Political considerations obviously play a part in where time zone boundaries are set. In the U.S., Indiana probably holds the record for the most confusing divisions. In China before 1949 and the Communist takeover, China had a very sensible five time zones. From 1949 forward, the entire country observes a single standard time, although in the far western provinces there are unofficial variations. For China’s easternmost province, this leads to the ridiculous clock time for sunrise on July 1 of 3 am! This map beautifully illustrates worldwide offsets between solar time and clock time.
Our clock time is geared as closely as is practical to solar time without having multiple different clock times for nearby locations. Except, of course, when we observe Daylight Saving Time. I’ll close with a story that is almost certainly not true, but ought to be. Supposedly a Native American chief who first heard of DST remarked “Only the white man’s government would be so stupid as to cut a foot off the top of a blanket, sew it onto the bottom, and think they have a longer blanket.”