The Five Biggest Surprises From The History Of Timekeeping – Forbes

Today is the release date for the UK edition of A Brief History of Timekeeping (the US edition came out last Tuesday), and Ive been doing a lot of publicity interviews on both sides of the Atlantic. One of the most frequent questions Ive been asked in this process is Whats the most surprising thing you learned in researching this book? and that seems like a decent topic for a publication-day post.

Before I go into the list, though, one important note of background: my training as a professional physicist mostly took place at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD, and the people in the lab next door to mine were literally working on an improved cesium atomic clock. As a result, Im a little jaded when it comes to modern clocks based on quantum physics, just because theyre so familiar to me. That means most of the things that surprised me come from the realm of history.

Anyway, with that out of the way, heres a list of things I found surprising when I began digging into the subject for the course that eventually became the backbone of the book:

IRELAND - NOVEMBER 14: Newgrange Stone Age Passage Tomb (Unesco World Heritage List, 1993), County ... [+] Meath, Ireland. ca 3200 BC. (Photo by DeAgostini/Getty Images)

Precision Timekeeping Is Really Ancient:

I sort of knew this going in, because I always planned to start the story with neolithic solstice markers like Newgrange and Stonehenge. But it was still remarkable to me to learn how long ago a lot of the key elements of astronomical timekeeping were known. The basic idea of making a solstice marker is really simple it just needs a couple of sticks and some patience so its not that surprising that people could manage it thousands of years ago. But lots of other fairly sophisticated bits of science and technology are also thousands of years old. Around 1500 BCE, an Egyptian court official bragged named Amenemhet bragged about inventing a water clock that could keep accurate time through the whole year, which is probably the ancestor of the Karnak clepsydra, whose tapered shape provides a remarkably constant flow rate, and whose seasonal markings reflect a good knowledge of the changing length of the days. The Egyptians were aware of the 1400-year Sothic cycle describing the drift of a 365-day year relative to the seasons (because their civilization lasted long enough to see it, twice), and the Babylonians knew about the Metonic cycle of adding months to keep a lunar calendar in synch with the seasons and the Saros cycle of eclipses for several centuries BCE. Thats a depth of history thats really impressive.

Tablet, Old Babylonian, circa 1800-1600BC. Astronomical Tablet showing the risings and settings of ... [+] Venus. cuneiform script. Dimensions: height: 7.5 cmwidth: 9 cmthickness: 2.8 cmArtist Unknown. (Photo by Ashmolean Museum/Heritage Images/Getty Images)

Some of the Most Important Innovations Are Anonymous:

We can attach names to some really ancient timekeeping discoveries Amenemhet and his clepsydra, Meton of Athens and the cycle he cribbed from the Babylonians but some much more recent inventors remain anonymous. We have no idea who invented the first mechanical clock, for example verge-and-foliot clocks spring up in medieval Europe, and spread rapidly across the continent, but theres no clear record of their invention, or who was responsible. Similarly, we have no idea who made the first sandglass they just start showing up all over the place. There are scattered claims that one person or another invented these things, but most of those werent written down until centuries later, so theyre doubtful at bet.

UNITED KINGDOM - APRIL 18: Oil on canvas painting by Thomas Hudson (1701-1779), showing Graham ... [+] (1673-1751) seated beside a mercury compensating pendulum in an open clock case, c 1710. Following his apprenticeship with London clockmaker Henry Askem, Graham, the inventor of the mercurial pendulum, was considered one of the greatest instrument makers of his day. He made various astronomical instruments, and contributed significantly to the advancement of precision timekeeping. Dimensions (unframed): 1200mm x 960mm. (Photo by SSPL/Getty Images)

Increases in Precision Can Be Astonishingly Rapid:

Prior to the 1600s, few clocks had minute hands because most mechanical clocks werent accurate enough for it to be worthwhile they would require re-setting by checking against the sun on a regular basis. When Galileo Galilei was doing experiments on free fall and pendulum motion, and Tycho Brahe was making the astronomical observations that led to our modern understanding of the solar system, they mostly used water clocks as few if any mechanical clocks of the time were up to the task. The first pendulum clock was built in 1657; within 60 years, George Graham and John Harrison in England were making pendulum clocks that compensated for changes in temperature to such a degree that they were good to around one second a month. We see similarly rapid increases in precision with the introduction of quartz clocks in 1930, and atomic clocks in 1955, and arguably with laser-cooled fountain clocks circa 2000 and optical-frequency clocks in the following decade. These are now accurate enough to measure the gravitational influence on time from an altitude change of centimeters. When scientists and engineers get hold of a good new way to keep time, they turn it into a great way to keep time in a hurry.

[UNVERIFIED CONTENT] Multi-face public clock in a ball shaped brass housing in front of the US flag ... [+] in Grand Central Terminal from low perspective framed with two chandelier

Time Zones Are a Corporate Creation:

In the book, I describe the introduction of time zones in the US as happening via a quinessentially American process: introduced by massive corporations acting to pre-empt legislation. The first national system of standardized time zones came in in 1883, replacing a patchwork of local times based on the sun with a system of broad zones based on the boundaries between rail companies. This was largely the work of William Allen, the Secretary of the General Time Convention of the railroad association, who explicitly wrote that the railroads should adopt his standarization scheme because there is little likelihood of any law being adopted in Washington... that would be as universally acceptable to the railway companies. The companies agreed, and signed on to Allens plan, and lobbied state and local governments to synchronize their clocks with railroad time, rather than the other way around. (I wrote more about this a few months ago here.)

Ambrogio Lorenzetti (Italian, 12851348), Allegory of Good and Bad Government: Good Government, ... [+] fresco, 1338-9, Palazzo Pubblico, Siena, Italy (Photo by VCG Wilson/Corbis via Getty Images)

Sandglasses and Mechanical Clocks Were Invented at the Same Time:

This stands as the single most surprising thing I learned in the process of research for this book. If you look at a sand timer, it seems like an incredibly ancient technology, something that mustve been in use since Egyptian times. In fact, though, the earliest unambiguous reference to a sandglass that we know of is its appearance in a fresco in Siena, Italy, painted in the 1330s. Its just... there in a way that suggests the artist knew it was something the audience would recognize, so they had probably been around for a while, putting the invention sometime in the 1200s. Which is also when the first verge-and-foliot mechanical clocks start popping up in church towers all over Europe.

So, while a sandglass seems like something incredibly old, and ticking mechanical clocks feel relatively modern, theyre actually invented at around the same time. That was really surprising to me, actually the single most surprising fact that I learned in this process. (But again, Im a weirdo physicist who knew a lot about atomic clocks before starting...)

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The Five Biggest Surprises From The History Of Timekeeping - Forbes