At precisely three minutes and thirty seconds before two o’clock on the afternoon of Friday, April 10, 1896, on a bridge in the Greek town of Marathon, an army officer named Papadiamantopoulos fired a revolver into the air and set the first-ever Olympic marathon in motion. Seventeen runners from five nations ran the forty-kilometre course to Athens, in foul weather and along a rough road that had been cleared of traffic for the occasion. The eventual winner, Spyridon Louis, from Greece, finished the race in two hours, fifty-eight minutes, and fifty seconds. Timing the event was a marathon unto itself: the same stopwatch held by the judge at the start of the race had to be carried by bicycle, ahead of the runners, to the finish line.

Timing is everywhere in today’s Olympics, and it has become all but instantaneous. In 1948, when the first photo-finish camera—nicknamed the Magic Eye—was introduced to the Games, sprinters had to wait for minutes while the film was developed to see who’d crossed the line first; now the final times and places are visible to the world before the competitors have come to a halt. The first Olympics, in 1896, featured two hundred and forty-one athletes competing in forty-three events across nine sports—a manageable task for a few judges holding stopwatches. The Winter Olympics in Pyeongchang, which begin Friday, will feature three thousand athletes in more than a hundred events. Before the Games end, Omega, which has provided the official timekeeping services to the Olympics since 1932, will serve up more than half a million finish times, splits, distances, rankings, and scores—a feat that requires two hundred and thirty tons of timing equipment, including more than a hundred miles of cable.* The modern timers are far more accurate than the old ones but far less portable.

The fact is that it takes time to measure time; the challenge of Olympic timing through the decades has been to make that measurement as quickly as possible. Watches capable of discerning hundredths of a second were in regular use in the Olympics by 1948. But what good is such refinement if, when an athlete crosses the finish line, the judge drops a tenth of a second or more merely clicking the stopwatch? (Human thought takes time to propagate and enact, too.) The weakness of this link became terribly apparent during the 1960 Summer Olympics, in Rome, when two swimmers, the American Lance Larson and the Australian John Devitt, seemingly tied in the hundred-metre freestyle. A half-dozen judges, peering through the waves at the finish, reached a stalemate: three declared Larson the winner, the other three Devitt. Though Omega’s stopwatches indicated that Larson had the faster time, by at least a tenth of a second, a referee broke the tie and awarded Devitt gold.

Slowly but surely, the human eye has been relieved of its timekeeping duties. With the début of the Magic Eye technology, at the 1948 Winter Games, in St. Moritz, Switzerland, came the electronic finish line—a thin beam of light that, when broken by an athlete, stopped the clock to the nearest hundredth of a second. (In 1992, the new Scan-O-Vision system increased accuracy to thousandths of a second.) The clock was connected to the starting gun, to further reduce any delay. But the gun had its own problems: the athlete nearest to it would hear the sound first and gained a slight advantage. So, in 2010, Omega introduced an electronic starting pistol, which resembles an oversized glue gun and emits a sound through speakers equidistant from every athlete. (It’s also viewed more kindly at airport security.) In downhill skiing, the athlete now has a ten-second window, announced by a series of beeps, in which to leave the starting gate; doing so prompts the clock to begin. And, after the debacle in Rome, swimming events introduced the touch pad, a sensitive force-plate at the finish of each lane; the first swimmer to trigger it is the winner.

In effect, each athlete now controls his or her own clock, determining when it stops and starts and, increasingly, carrying it along the way. Speed skaters wear transponders on their ankles that mark their location, speed, and running time at every moment along their path; alpine skiers have them on their boots. Many of the temporal innovations this year have less to do with timing, per se, than with its permutations: the real-time acceleration rate and brake speed of speed skaters and alpine skiers; the takeoff and landing speeds of snowboarders; g-forces in the bobsleigh. It’s a continuous stream of entertaining data, but it can also be fed back into the training process, helping athletes to understand where they gained or lost time.

Perhaps the biggest temporal novelty in Pyeongchang is a new event, mass-start speed skating. In mass start, all the competitors—as many as twenty-four—are on the ice at once, racing to complete sixteen laps around the four-hundred-metre-long oval. The fourth, eighth, and twelfth laps are sprints, with the first, second, and third skaters to finish gaining, respectively, five points, three points, or one point. There’s a final sprint, too, offering even more points, which factor into the ranking of the top three competitors.

FURTHER READING Coverage by New Yorker writers of the 2018 Winter Olympics.

It’s a swirling, complex timing challenge, impossible to parse accurately without all that modern technology. But the real timing benefit accrues to the viewer. The traditional ten-thousand-metre speed-skating race can be, let’s be honest, tedious—two racers at a time, a dozen-plus minutes per trial, again and again. In contrast, the mass start offers a jumble, a mad dash, and, inevitably with so many racers on the ice at once, the thrilling prospect of disaster. “This will get people looking at long-track and say, ‘OK, this is a little bit like Formula One,’ ” the U.S. speed skater Joey Mantia, the reigning world champion in the mass start, recently told the Associated Press.

Naturally, over time, timing technology will only improve. At the 2012 Olympics, in London, Omega introduced two timers—the Quantum Timer and the Quantum Aquatics Timer—capable of measuring accuracy to a millionth of a second, although nobody has yet figured out what to do with them. Olympic times are typically displayed to the hundredths of a second, or at most to the thousandths. In 2012, at the U.S. Olympic sprinting trials, Allyson Felix and Jeneba Tarmoh managed to tie for third place—and for the third and final spot on the Olympic squad—with a time of 11.068 seconds. After debating for twenty-four hours, the judges offered the runners their choice of tiebreaker: coin toss or runoff. (Tarmoh eventually chose to cede the spot.)

It’s unlikely that still-finer scales can reveal anything beyond the fragility of the whole enterprise. In 1984, at the Los Angeles Olympics, two American swimmers, Carrie Steinseifer and Nancy Hogshead, tied in the hundred-metre freestyle, each with a time of 55.92 seconds. They didn’t bother appealing to the thousandths of a second, and were content to share the gold. “It wouldn’t have said who really won,” Hogshead said later. “All it would have told us is that maybe somebody’s lane is a thousandth of a second shorter. A hundredth is a tiny amount of time, and a thousandth is a sliver of a sliver.”

The story of Spyridon Louis, the winner of the 1896 marathon, holds that, ten kilometres from the finish, Louis stopped at an inn, where he was given half an orange by his girlfriend and a glass of cognac by his future father-in-law. Several runners were ahead of him, including the favorites, Albin Lermusiaux, of France, and Edwin Flack, of Australia, but Louis announced that he would pass them all. Within five kilometres, he did. Who wouldn’t love to see a little more of that? Nowadays, the only people who can pause are us, the viewers, for a glass of cognac or half an orange, before we hit “play” again and pick up the Games right where we left off.

*Correction: An earlier version of this article misstated the total tonnage of Omega’s equipment at the 2018 Winter Games.