It’s time to do away with the leap second, which is scheduled to happen in 2035.
This was decided by a vote at a Friday meeting of signatories to the International Treaty on Standards in Measurement and Science at Versailles, France. For several metrologists throughout the globe, finding a solution to the leap second issue has been an ongoing battle for decades, thus the almost unanimous vote on Resolution D was hailed with relief and celebration.
The International Bureau of Weights and Measures‘ director of time, Patrizia Tavella, called the vote “unbelievable” in a WhatsApp message immediately after it was announced. After over two decades of negotiation, we’ve reached a fantastic arrangement. She even said she was “brought to tears” by it.
The United States strongly backed the measure. Elizabeth Donley, head of NIST’s time and frequency branch in Boulder, Colorado, said, “It seems like a momentous day.” And I really miss being there. It’s likely that many lavish parties are being thrown in honour of the occasion.
Since its conception 50 years ago, the leap second has been a source of contention. It was conceived as a means of synchronising the somewhat slower time that Earth retains as it revolves with the international atomic time scale, which has been in use since 1967 and is derived from the vibration of cesium atoms. When atomic time is ahead by one second, it effectively pauses for a second to let Earth catch up. As part of the compromise announced in 1972, ten leap seconds were added to the atomic time scale. The number has increased by twenty-seven since then.
Adding those few seconds in 1972 was difficult, and the technological challenges are far worse now. Since it’s difficult to know when the next leap second will be required, it’s impossible for computer systems to be ready for them in a timely fashion and in a regular pattern. Uncoordinated efforts by various networks to account for the additional second have resulted in a patchwork of solutions.
In addition, today’s interconnected worldwide computer systems need very exact timing, down to the billionth of a second. If we add one more second to the clock, there is a greater chance that the systems that run our communications networks, power grids, banking, and other essential services may malfunction or get out of sync.
Coordinated Universal Time (UTC), the official worldwide time standard, has been gradually supplanted by alternative time systems. Getting rid of the leap second is considered as a strategy to keep people using UTC by making it a continuous time scale instead of one that is sometimes disrupted.
According to NIST physicist Judah Levine, “the most critical concern is the preservation of the idea that time is an international quantity.” He referred to the Versailles settlement as “an great stride forward.”
For the record, Russia was a no vote on the resolution, while Belarus was a no-show. Since its GLONASS global navigational satellite system includes the additional seconds, unlike other systems like GPS, which is run by the United States, Russia has long pushed to postpone retirement of the leap second. Given Russia’s reservations, the elimination of the leap second is not expected to take place until at least 2035.
From 2035 until at least 2135, metrologists are tasked with finding a way to balance the atomic and astronomical time scales with little disruption to U.T.C., as called for in Resolution D. For future generations, the synchronisation between the international standard time and astronomical time will be broken.
However, according to the Rev. Pavel Gabor, an astronomer and the deputy director of the Vatican Observatory Research Group in Tucson, Arizona, reuniting these two time periods was crucial. According to him, atomic timekeeping is only one example of how the world is becoming unintelligible to the ordinary person, and scientists have a duty to make people feel like they are in charge of their own life again.
The eradication of the leap second will need more work. The Coordinating Board for International Time is in charge of setting universal time, while the International Telecommunication Union is in charge of getting that time to everyone. Also in 2019, delegates at the I.T.U.’s World Radiocommunication Conference in Dubai, United Arab Emirates, will cast their ballots on the topic. Former B.I.P.M. director and current visiting astronomer at the Paris Observatory Felicitas Arias has claimed that talks between the two organisations have persuaded her that the I.T.U. would back the Versailles vote.