A Matter of Time

Measuring time - Exceptions to time measurement

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No system is perfect. It has taken astrologers, scientists, and mathematicians alike, centuries to construct the calendars and clocks we revolve our lives around to today. Even after centuries of hard work and continual modifications, there are still flaws in our time keeping processes that occasionally arise and need to be dealt with. No sooner does a problem pop up however, than someone comes up with a mechanism to remedy it.

The earth does not orbit the sun in an exact number of days. After three-hundred-sixty-five days, the earth is one fourth of a day behind the original point it was at three-hundred-sixty-five days earlier. Therefore, after four years, the earth is a full day behind where the calendars say it should be. Leap years are thus implemented as a catch up tool.  Once every four years, an extra day is added to the month of February to accommodate this missing day.

We now measure precise time using atomic clocks.   The earth’s rotation however, is constantly slowing down due to the breaking action of the tides.  Since the earth is slowing down relative to atomic clock time, we lose a fraction of an atomic clock second each time the earth rotates on its axis.  To compensate for this loss and keep the atomic clocks synchronized with the earth’s rotation, a leap second is sometimes inserted (usually on New Year’s Eve).  The first leap second was added in 1972 and 21 others have been added since then.

Although it is not used in quite the same way as leap years and leap seconds,  daylight saving time serves an equally influential purpose. It compensates for alterations in time caused by fluctuations in the earth’s movement. Near the equator, days and nights are approximately twelve hours each. The further north or south one travels from the equator however, the more that daytime hours extend significantly during that hemisphere’s summer months. By moving the clocks forward an hour it gets darker later, thereby allowing people to take advantage of the larger amount of light in the evenings. Surveys conducted by the US Department of Transportation as well as polls taken of the population in New South Wales, Australia indicate that this feeling of maximum daytime is the reason that most people have no qualms with daylight saving –or, as it is commonly, though inaccurately known, “daylight savings” (webexhibits). Daylight Saving time serves a dual purpose as well by cutting down on the amount of electricity needed for lighting, and thus decreasing the overall energy consumption anywhere from 1% to 5% nationwide. In addition to recreational and electrical benefits, it has been noted that the extra daylight decreases the number of car crashes in the evenings.

Opponents of daylight saving time however will be quick to point out that the number of automobile related incidents and their severity increases in the darker mornings, resulting in more fatalities. Even safe drivers will undoubtedly be affected by the needed shift in sleep schedules, which poses an even greater problem for those with sleeping disorders. Arguments have also been made against the claim of energy conservation, saying that people use more gasoline during the extra daylight traveling around. Some “ultra-Orthodox Sephardic Jews [in Israel] have campaigned against DST because they recite Slikhot penitential prayers in the early morning hours during the Jewish month of Elul (webexhibits).

The idea of daylight saving time originated with Benjamin Franklin.  It was introduced to the British House of Commons in 1909 but was not instituted until World War Two. From 1966 until 2005, the DST took place from 2:00AM on the first Sunday in April until 2:00AM on the last Sunday of October.  In 2005 however, George W. Bush signed the Energy Policy Act, pushing the dates for DST back to March and forward to November, beginning in 2007.

There are many parts of the world that don’t practice daylight saving time, including some U.S. states such as Hawaii and Arizona and some U.S. territories such as Puerto Rico, the Virgin Islands, and Guam. Japan and India are at the top of the list of countries that don’t  have any DST at all.  In addition, the countries in the tropics have no need for it, and China stopped observing it in 1991.

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