Time Travel. A History

A century after Einstein discovered that perfect simultaneity is a chimera, the technology of our interconnected world relies on simultaneity as never before. When telephone-network switches get out of sync, they drop calls. While no physicist “believes in” absolute time, humanity has established a collective official timescale, preached by a choir of atomic clocks maintained at a temperature near absolute zero in vaults at the United States Naval Observatory in Washington, the Bureau International des Poids et Mesures near Paris, and elsewhere. They bounce their networked light-speed signals to one another, make the necessary relativistic corrections, and thus the world sets its myriad clocks. Confusion about past and future cannot be tolerated.

To Newton this would make perfect sense. International atomic time has the effect of codifying the absolute time that he created, and for the same reason: it lets the equations work out and the trains run on time. A century before Einstein, this technical achievement in simultaneity would have been almost impossible to conceive. The very notion of simultaneity scarcely existed. It was a rare philosopher who considered the question of what time it might be in a faraway place. One could hardly even hope to know, said the doctor and philosopher Thomas Browne in 1646,

It being no ordinary or Almanack business, but a probleme Mathematical, to finde out the difference of hours in different places; nor do the wisest exactly satisfy themselves in all. For the hours of several places anticipate each other, according to their Longitudes; which are not exactly discovered of every place.

All time was local. “Standard time” had no use before the railroad came and could not be established before the telegraph. England began synchronizing its clocks (new expression) to railway time in the mid-nineteenth century, when telegraph signals went out from the new electromagnetic clock at the Royal Observatory in Greenwich and the Electric Time Company in London. Also to the newly coordinated clock towers and electric street clocks of Bern.^*6 These were technologies on which the ideas of Einstein depended, and also the ideas of H. G. Wells.

So now, on a hilltop near the Potomac River, the United States maintains a Directorate of Time, a subdepartment of the navy and by law the country’s official timekeeper. Likewise in Paris is the BIPM, which also owns the international prototype of the kilogram. These are the keepers of temps universel coordonné, or coordinated universal time, or UTC—which I think we can admit is arrogantly named. Let’s just call it Earth time.

All the chronometric paraphernalia of modernity: scientific, and yet arbitrary. Railroads made time zones inevitable, and in hindsight we can see that time zones already entailed a sense of time travel. They were not organized all at once, by fiat. They had many beginnings. For example, on November 18, 1883, a Sunday, known afterward as “the Day of Two Noons,” James Hamblet, general superintendent of the Time Telegraph Company in New York City, reached out his hand and stopped the pendulum of the standard clock in the Western Union Telegraph Building. He waited for a signal and then restarted it. “His clock is adjusted to hundredth parts of a second,” reported the New York Times, “a space of time so infinitesimal as to be almost beyond human perception.” Around the city, tickers announced the new time and jewelers’ shops adjusted their clocks. The newspaper explained the new setup in science-fictional terms:

When the reader of The Times consults his paper at 8 o’clock this morning at his breakfast table it will be 9 o’clock in St. John, New-Brunswick, 7 o’clock in Chicago, or rather in St. Louis—for Chicago authorities have refused to adopt the standard time, perhaps because the Chicago meridian was not selected as the one on which all time must be based—6 o’clock in Denver, Col., and 5 o’clock in San Francisco. That is the whole story in a nut-shell.

Of course, that was nothing like the whole story. Arbitrary as they were, the railroads’ time zones did not please everyone, and a new oddity followed: Daylight Saving Time, as it was known in North America, or, as Europeans called it, Summer Time. Even now, after a century of experience, some people find this twice-yearly time jump disturbing, and even physically uncomfortable. (And philosophically unsettling. Where does the hour go?) Germany was the first to impose Sommerzeit, during World War I, hoping to save coal. Soon after, the United States adopted it, then repealed it, then reimposed it. In England, seeking evening light for hunting, King Edward VII had the clocks on the royal estate set to “Sandringham Time,” a half hour ahead of Greenwich. When the Nazis occupied France, they ordered all the clocks moved an hour forward, to Berlin time.