When A Day Is 23-Hours Long

The clocks moves daylight. Seemingly. In spring, at the beginning of D.S.T., it moves forward; advances by on hour forward (right.) In fall, when D.S.T. ends, it’s set back by an hour (left.)

We were up at our regular hour. Yet, we were late to rise. At 2:00 a.m. sharp, while we were asleep, the clock had quietly leaped from 1:59 standard time to 3:00 daylight saving time (or D.S.T.) Little wonder then that our Sunday felt shorter, shrunk that it had by an entire hour.

Daylight saving time is a temporal convention, where the clock moves forward an hour in spring and an hour backward in autumn. In winter, when daylight saving time ends, we get an extra hour of sleep. But on the flips side, there’ll be much less light in the evening. People who work from 9 a.m. to 5 p.m. leave their offices in total darkness.

The concept dates back to Benjamin Franklin. In 1784, while living in France, in a tongue-in-cheek letter to the Journal of Paris—later, published as an essay, titled, “An Economical Project”—he wrote that it’d be thriftier to harness the light of the Sun than to work by the dim glow of oil lamps and candles.

He’d calculated that Parisians wasted 64 million pounds of tallow and wax every six months because they stayed up after sunset and slept until noon. He proposed that “every morning, as soon as the Sun rises, let all the bells in every church be set ringing … let cannon be fired in every street, to wake the sluggards effectually. Let a tax be levied on every window, provided with shutters to keep out the sunlight.”

We will never know if he’d intended anyone to take his suggestion seriously, of course. But eventually, it was—though not in regard to candles, but clocks. Germany was the first nation to adopt daylight saving time in 1916 as an austerity measure to save coal.

The U.S. followed in 1918. It was repealed in 1919, after World War I ended, only to be brought back in 1942, during World War II. It went into effect, again, in 1967, and has stayed on, even though it has been revised many times.

The phrase “daylight saving time” is grossly misleading, for you can no more save daylight than you can wrap Deimos in a big garbage bag. As Karen Thompson Walker, author of the novel, “The Age of Miracles” puts it in the New York Times: “By moving our clocks forward one hour, we agree to change merely our perception of daylight, not daylight itself.”

The argument in favor of resetting the clocks—or moving sunlight from the morning to the evening—is that it reduces energy consumption. When the clock skips an hour ahead, we’re forced to drag ourselves out of bed at 5:00 a.m., instead of 6:00 a.m. Because it’s dark at that hour, in most instances, we have to switch on the lamps. Sure, we burn electricity in crepuscular dawns. But the energy expended at sunrise is more than offset for by the energy savings at sunset as brighter nights reduce the need for artificial illumination.

That’s the line of thinking behind daylight saving time. But we do need it? As we edge towards summer solstice, the Sun will rise progressively earlier, and set progressively later. In midsummer, it’ll be up as early as 5:30-ish a.m. and go down as late as 8:30-ish p.m. The daylight hours will get longer, being the longest on June 21, stretching for a little over 15 hours.

One doesn’t flip light switches on mindlessly, by looking at the watch, but by looking at the level of brightness in the rooms. Even without daylight saving time, sensible folks would still know not turn on a 75-watt lamp, if the dining room is bathed in a noon-like glare.

The difference between standard time and solar time.
The difference between standard time and solar time.

This map, created by Google engineer Stefano Maggiolo, indicates the futility of telling time by the clock. He shows the wide difference between “standard time” and “solar time” (a schedule that sets time by the Sun’s position in the sky, in which 12:00 p.m. is observed when the Sun is at its highest point in the sky.)

In most parts of the world, the Sun rises and sets after the standard time. Places where the Sun sets “later”—that is, after standard time—are shown in red. Areas where it sets “earlier”—that is, before standard time—are colored green. The deeper the shade, the more is the difference between clock time and solar time.

In China, which has a single time zone, all the clocks are calibrated to Beijing’s time. An inconvenient side effect of this is that by the time the Sun is at its brightest in the far-western province of Xinjian, it’s already mid-afternoon, about 3 p.m.

At the other end of the spectrum is the case of India’s northeastern state of Assam. In summer, while in most regions of the country, first light doesn’t break at 4:30 a.m., in this region, the Sun has made its appearance and begun its imperceptible ascent across the horizon. It could well be very well-lit out, but the clocks tell that it’s not quite time to begin the day yet.

When all is said, to me, nothing heralds the approach of summer like the sound of Mister Softee, winding through the streets.

h/t: DAYLIGHT SAVING TIME and THE POOR MAN’S MATH BLOG

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