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Anthropology in Practice

Anthropology in Practice

Exploring the human condition.

The End of the Time of Earth: Why Does the Leap Second Matter?

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Dial of the Prague astronomical clock. Creative commons. Click on image for license and information.

Ed Note: We have a guest today! AiP is pleased to host this post by Dr. Kevin Birth, who is a professor of anthropology at Queens College, CUNY and an expert on time. His forthcoming book, Objects of Time: How Things Shape Temporality (Palgrave Macmillan) discusses the hidden logics in clocks and calendars.

As a specialist in the study of time, I occasionally get asked about what I think of the so-called Mayan prophecy that the world will end in 2012. I guess people think that I’ll have some interesting insight into the cultural anthropology of time, and some special knowledge into the mysterious Mayan logics. Truthfully, it is not the Mayan logics that are mysterious, but our own. 2012 was almost a significant year in the cultural creation of time as we know it. Recently, those in charge of the global time system decided to defer to 2015 the ending of the time of Earth. Because of the timing of the debate over Earth’s time, it may come as a shock to those who expect some dismissive answer from an ivory-tower intellectual, but I think the Maya maybe were on to something.

The Mayan calendrical system consists of multiple cycles of different durations. Like a set of different-sized gears whirring together with gears completing their cycles at different times, it takes a long time for the Mayan system to return to a previous state. The Gregorian year 2012 marks a moment when this Mayan system will start over—the end of the old long count and the beginning of a new one. The Maya took such things very seriously, and as Professor Prudence Rice has demonstrated in her books, the ending of one cycle and beginning of a new one coincided with political transformations for the Maya.

The Maya are not alone in such a sensitivity. People in the European tradition are enamored of base-10 mathematics, so when the year 2000 approached, there was a great deal of hoopla over the number. Many saw it as the beginning of the new millennium, although, in truth, the millennium did not begin until 2001. Still, there seems to be magic in chronological numbers and their cycles.

But there is another thing going on in all these calendrical and chronological systems. Behind the curtain of these cycles are a set of logics that deal with some fundamental problems in time keeping. This is as true for us as it was for the Maya. First, the cycles of the moon, stars, and sun are not equivalent. Second, the revolution of the Earth around the sun is an awkward 365.242 days. Different cultures have come up with different solutions to this problem, and the Mayan calendar is just one of many such solutions. Our currently dominant calendar, implemented by Julius Caesar and tweaked by Pope Gregory the XIII, ignores sidereal and lunar cycles, and deals with the duration of the Earth’s orbit through leap years that add a day.

Whether it is ancient Maya or our contemporaries in 2012, most people have very little idea of how systems of time reckoning are created—we simply look at our clocks and calendars and believe them without recognizing the cabal of astronomers and/or priests that lurk behind the logics. Through our objects of time, we rely on largely unknown experts to make sure that the trains and everything else run on a reliable time, and to ensure that we know when the airlines do not. All we need to know is how to read a clock and calendar, not how they work.

While almost everyone is familiar with the idea of the leap year, far fewer are aware that the Earth’s rotation is not uniform. It wobbles about with small deviations, and as a result, a international bureaucracy has been set up to keep our time system coordinated with the Earth’s foibles. In this bureaucracy, the International Earth Rotational Systems Service (IERS) has charted the Earth’s rotation and when necessary, made recommendations to the International Bureau of Weights and Measures (BIPM) to modify the international time keeping system by a second—a leap second. The BIPM receives time signals from atomic clocks distributed throughout the globe and then calculates what is called “coordinated time” based on these signals. This created, coordinated time is then set to the prime meridian, and sent back out to all those in the time signaling business as something called “Universal Coordinated Time” (UTC). It may be disconcerting to hear that time is created, but if one keeps in mind the theory of relativity, each point in space has its own unique time. From the perspective of relativity, a universal time is an illusion—but an illusion our society needs to function.

The BIPM creates time by following policies formulated by the Radiocommunications Sector of the International Telecommunications Union (the ITU-R). There are many technologies reliant on time, such as software and GPS, and these technologies do not work well with the Earth’s occasional hiccups and the irregular insertion or deletion of seconds from UTC. Since much software runs on a uniform time without leap seconds, to keep it coordinated with UTC requires software updates, and this gets expensive over time.

The recent consideration by the ITU-R to do away with leap seconds would have meant an end the time of Earth—in effect, the Earth’s cycles would no longer have a bearing on the time kept by clocks. In this culturally created system, the units of duration that define time for us are a choice of the ITU-R. A second is defined as 1/315,56,925.975 of the length of the tropical year for January 0, 1900 (in effect, December 31, 1899); a day as 86,400 of those seconds; a year as 365 or 366 (in a leap year) of those days. This decision would have meant our clocks are not tied to the Earth’s rotation, and our calendars are no longer associated with the Earth’s orbit—truly, the end of the time of Earth.

In an uncanny coincidence, this debate is unfolding at the end of the Mayan long count—the end of one time for the Maya and the beginning of a new one. A cataclysmic change that few will notice as global time ceases to refer to any single cycle but becomes entirely a cultural creation.

So maybe the time conscious Maya were right, but it is not the world that ends in 2012, only time as we knew it. However, since the decision has been delayed to 2015 it seems we have little to worry about, assuming we understand the Mayan calendar correctly (and that’s a big assumption).

The views expressed are those of the author and are not necessarily those of Scientific American.

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