Timekeeping Is A Universal Human Obsession
By: Chad Orzel
For many of us, this is a part of the year when we are acutely aware of time and timekeeping, even more so than usual. Thanks in part to the changing of clocks I talked about in my last post, it gets dark much earlier, and there’s another month or so to go of the days getting shorter and the nights longer (in the northern hemisphere, anyway; if you’re in most of South America, much of Africa, or Australia, enjoy your long summer days...). We’re also coming into the cluster of solstice-related holidays— Hanukkah started last night, and Christmas is fast approaching— so a lot of kids are counting down days, and adults juggling family and social commitments and trying to find time to shop for gifts.
The preceding might make this seem like a particularly Western preoccupation. That’s true in a narrow sense— the holidays of the moment are Jewish and Christian, and there’s nothing all that significant happening in, say, the Muslim world for the next couple of months— but in fact basically every human culture we know much about has devoted significant energy to the tracking of time.
For much of human history, this was a matter of life and death, thanks to the short days and long nights that make it difficult for an agrarian society to produce food in winter. For this reason, many of the oldest surviving human structures have a timekeeping function, related to tracking the seasons. One of the most spectacular of these is the passage tomb at Newgrange, near Dublin, an artificial hill made from 100,000 metric tons of rock and earth. The hill hides a narrow passage leading to a vaulted central chamber, which is aligned so that at sunrise on the winter solstice (and a few days to either side), a narrow ray of sunlight penetrates all the way to the center, the only light reaching that chamber all year. This clearly marks out the shortest day of the year, providing an essential reminder of the turning of the seasons and the promise of coming spring.
Newgrange dates from around 3200 BCE, making it one of the oldest such monuments in Europe, but it’s by no means a unique achievement as a timekeeper. Numerous other sites feature similar alignments with sunrise or sunset on the solstices or equinoxes, most famously the stone circle at Stonehenge, but also sites at Avebury in England, Knowth and Dowth in Ireland, Maeshowe in Scotland, and Bryn Celli Ddu in Wales. Piling up big rocks to track the passage of the year was a widespread activity in Neolithic Britain.
Marking these important points in the cycle of the Sun remained an important activity for thousands of years, and spurred other innovations in timekeeping across a wide range of cultures. One of the greatest achievements of medieval Chinese technology was prompted by an error in timekeeping: in 1077 CE, the Song Dynasty dispatched Su Song to offer winter solstice greetings to the neighboring Liao kingdom, but thanks to an error in the Song calendar, he arrived a day early, nearly creating a diplomatic incident.