Later this month, delegations from around the world will attend a conference in Dubai to discuss international treaties involving radio frequencies, satellite coordination and other thorny technical issues. These also include the problem of souring of watches.
For 50 years, the international community has carefully and precariously balanced two different ways of keeping time. A method based on the Earth’s rotation, an ancient and common-sense reliance on the position of the Sun and stars as old as human timekeeping. The second, more precise method links a stable, reliable frequency to the changing positions of the cesium atoms and provides the regularity needed for the digital devices that dominate our lives.
The problem is that time varies on these watches. Astronomical time, called Universal Time, or UT1, lags a few clicks behind atomic time, called International Atomic Time, or TAI. So every few years since 1972, the two times have been coordinated by the insertion of a leap second – atomic clocks are stopped briefly to catch up with the astronomical clocks. This creates UTC, Universal Coordinated Time.
But it is difficult to predict exactly when a leap second will be needed, and this has created an intense headache for technology companies, countries and the world’s timekeepers.
“Dealing with leap seconds drives me crazy,” said Judah Levin, Boulder, Colo. Head of the Network Synchronization Project in the Time and Frequency Division at the National Institute of Standards and Technology in Washington, D.C., where he is a leading thinker on the coordination of world clocks. He is constantly pestered for updates and better solutions, he said: “I get billions of emails.”
On the eve of the next international discussion, Dr. Levin has written a paper that proposes a new solution: the leap minute. The idea is to sync the clocks less frequently, perhaps every half century, essentially allowing atomic time to deviate from universe-based time by 60 seconds or so, and basically in the meantime Let’s forget about it.
“We all need to relax a little,” Dr. Levin said.
One world, two watches
The problems began in the early 1970s, with the beginning of the nuclear era. Until then, the world was largely dependent on astronomical time. This seemed logical – the sun rose and became day, then it set and became night and so on, although there were small irregularities due to the slow motion of the Earth’s rotation and other natural forces. These variations did not go unnoticed by humans. Not so much by machines.
Computers require precise, lock-step timekeeping so that their orders remain consistent. After the introduction of atomic timing, it became necessary for an increasing number of tasks – such as landing airplanes and timing stock trades – not without an increasing number of problems as society became more mechanized.
“Cesium clocks became very common, and a problem immediately arose,” Dr. Levin said. “The astronomical clock and the cesium clock began to move away from each other.”
The introduction of the leap second in 1972 codified that a second would be introduced whenever the two clocks were more than 0.9 seconds apart. It had at least three purposes: to keep time connected to the natural world and the tradition of astronomy; In line with digital technology; And to establish harmony and coordination between the two clocks. The leap second has been used 27 times in the last 50 years.
Around the turn of this century, another problem arose, driven by a new group of stakeholders: big technology companies. Companies such as Google, Amazon, and Facebook developed their own methods of harmonizing astronomical and atomic time, essentially bypassing the leap second. Meta, for example, “smears” leap seconds in millisecond increments over a 17-hour period., instead of making a sudden jump. But there are many approaches that make timekeeping a free-for-all and threaten uniformity.
“We have messed up time all over the world,” said Patrizia Tavella, director of the timing department at the International Bureau of Weights and Measures in Paris.
Dr. Levin, with his leap-minute solution, is highly respected among time-keeping scientists, said Demetrios Matsakis, former director of the U.S. Naval Observatory’s Time Services Division. (In 2009, Dr. Levin won the prestigious Time Lord Award given by the International Timing & Sync Forum).
For this and other reasons, Dr. Matsakis finds the new proposal attractive. “If they’re coming on strongly for a minute, that will be a new emphasis,” he said. “This is the kind of thing that can be resolved politically,” he said. “This just might be the winner.”
Then, he said, this proposal could, like previous proposals aimed at syncing the clocks, be stopped by an international community with vested interests and strong opinions.
“You’re dealing with mass hysteria,” Dr. Matsakis said.
Vatican and Russian
At one point last year, Dr. Tavella spoke to the Rev. Paul Gabor, an astrophysicist and deputy director of the Vatican Observatory Research Group in Tucson, Ariz., about the leap second. His concern, he said, was that “eliminating this idea might create some uneasiness, because humans feel connected and want to be connected to the natural world.” Also: “Men look to the sky and count the days; This is something ‘unspoken’ but deep in people’s hearts.”
Other timekeepers and diplomats felt that losing the leap second would break official time from the ancient traditions of astronomy and ultimately lead to the dominance of accurate but laboratory-made atomic clocks. between bitter rivals For many years the British government has controlled Greenwich Mean Time (now Universal Coordinated Time), an astronomical clock determined by averaging the Sun’s position throughout the year.
Dr. Levin said he sympathized. “The public has a huge distrust of scientists who are people who propose something that goes against common sense,” he said.
And yet, he said, the persistence of Daylight Saving Time seems to be an acknowledgment that people are “comfortable with changing the relationship between time and everyday astronomy.”
Over the past decade, the increasing challenges of implementing the leap second have driven a desire to replace the existing system. A big change happened last November When the member countries of the International Bureau of Weights and Measures announced that it was ready to explore alternatives to the leap second. No proposal was adopted, but the basis was laid for considering alternatives, such as eliminating the leap second or relaxing the relationship between astronomical and atomic time.
There were some objectors, particularly the Russians, who mysteriously argued strongly for placing the jump in second place. The speculation is that the Russian GLONASS satellite system is designed for leap seconds and that changes to the current timekeeping method could have military implications.
“Nobody fully understands it,” said Elizabeth Donnelly, head of NIST’s timing and frequency division. “It’s probably a national security matter. They never really have a good answer.”
Which brings the world community to the World Radio Conference, this meeting will start from November 20 in Dubai. The agenda calls for a discussion about the leap second, but American scientists are not optimistic that the talks will yield any results. Any proposed changes would require consensus among all attending countries, including Russia.
Dr. Matsakis is more hopeful that a new method can be codified in other conferences in the next two years, which does not require full consensus. For now, the leap minute proposal has just begun to circulate as part of a draft paper that has not yet received the full scrutiny it will have to withstand. Its formal publication may take place after Dubai, although word of it will have spread.
For Dr. Levin, a decision can’t come soon enough; He is tired of dealing with the leap second and feels that his own time is being wasted. “Now or never,” he said. “I am 84 years old.” “Actually I’m 83 years old, but my wife is 84 and I think of us the same age,” he said after a pause.
UST: Universal Spouse Time.
Despite this, he said, “I won’t be around forever.”
