A Brief History of Timekeeping: A new book explores how we mark time

HOW did humans progress from measuring time with stone solstice markers to a smart watch on which it is also possible to read this review?

In A Brief History of Timekeeping, Chad Orzel, physicist and author of bestselling book How to Teach Quantum Physics to Your Dog, turns his enthusiasm for time travel to something more tangible: how humans through the ages have measured the passage of time.

It may seem like being ruled by the clock is a relatively recent phenomenon, but Orzel argues that it has been “a major concern in essentially every era and location we find evidence of human activity”.

Thanks to a 1960s excavation of a site in east Ireland, for example, we know that the 5200-year-old tomb Newgrange was built by people with enough astronomical knowledge to create an opening that focuses a shaft of light onto the back of the chamber at sunrise on the winter solstice.

Knowledge of the movement of stars remains important today in our understanding of time, says Orzel. It explains, for instance, why religious holidays change dates from year to year. Yet the calendar is also a social construct, representing a delicate balancing act between stellar movement, bureaucracy, ritual and religion. The overnight jump from Wednesday 2 September to Thursday 14 September when Great Britain adopted the Gregorian calendar in 1752 is a case in point.

Orzel’s enthusiasm for the past is balanced by his disdain for modern misconceptions around time. He admonishes the flat-Earth conspiracy theory that has been promoted by celebrities like basketball player Kyrie Irving, and the way it disrupts geography and astronomy lessons in schools.

He also laments how the passing aeons often only become of interest to the public when they have something dramatic to say, such as the widely shared Mayan prophecy that the world would end on 21 December 2012. This was based on a fundamental misreading of the Mayan calendar system, says Orzel, who concedes that at least it made people more aware of the Mayans’ pioneering base-20 numerical system.

Throughout the book, Orzel scoots backwards and forwards in time, treating us to illustrations of spectacular forgotten timepieces. He explains how Athenian water clocks were used to limit speaking time in law courts, how a 12th-century Chinese water tower designed by Su Song became the basis for the modern mechanical clock, using a system of scoops, bronze spheres, counterweights and – crucially – a numbered face. Rod-based verge-and-foliot clocks followed in its wake, and Orzel details how these gave way to the pendulum, which reduced the number of missed ticks per day from several hours’ worth to just minutes.

The author’s enthusiasm doesn’t wane as he moves into the digital era, explaining how quartz-based wristwatches “democratised” time and serve as temporal “tuning forks” for the masses, before exploring how many of our modern devices sync up with caesium atomic clocks for the latest word in punctuality.

He also ponders how tomorrow’s quantum computers may prompt physicists to argue for the decimalisation of time. This has been attempted before, most recently by 19th-century French polymath Jules Henri Poincaré, who argued for splitting the day into 100 minutes made up of 100 seconds. This would be confusing for a generation or so, but as Orzel’s book makes clear, time, and its measurement, stands still for no one.

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