Time is up for the leap second. Last week, an international coalition of scientists and government agencies voted to retire the outdated timekeeping system, which will officially end in 2035.
The decision was made Nov. 18 during a general conference in France hosted by the International Bureau of Weights and Measures (BIPM), the organization responsible for global timekeeping.
Similar to leap yearsleap seconds are a measure of time that is periodically added to clocks to compensate for the difference between astronomical time (universal time 1 or UT1), also known as Landand Coordinated Universal Time (UTC), which is based on the atomic clock.
“As the Earth’s rotation continues to slow, it is one minute behind every century and one hour behind every 5,000 years,” Patricia Tavella (opens in a new tab), director of the BIPM’s weather department, told Live Science. Thus the leap second was invented.
First introduced in 1972leap seconds have long been the bane of timekeepers’ existence and are under increasing pressure for elimination as highly used technologies, such as satellite navigation, computer networks, telecommunications and aviation, increasingly require a ‘extreme precision in timing.
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In the beginning, 50 years ago, 10 leap seconds were added to the atomic time scale; over the next few years, 27 more additions were made each time the two time systems drifted more than 0.9 seconds apart, according to The New York Times (opens in a new tab).
The addition of leap seconds has created a host of problems and can lead to technical difficulties that can affect everything from financial transactions to energy transmissions, even the way astronomers align their telescopes (opens in a new tab).
“Leap seconds can be a source of failures and glitches in computer systems,” Tavella said.
As an example, Tavella pointed to the aviation industry, which relies heavily on accurate timekeeping to plan flight routes around the world.
“Because of the leap second, airlines have had problems with flight scheduling due to a time difference,” Tavella said, as different computer networks have developed their own methods of adding extra leap seconds. “You may get errors if there is no international sync when applying leap second.”
Tavella was quick to note that the average person most likely “won’t notice the change” and that instead of adding seconds on an annual basis, the new methodology will involve compounding seconds over the course of a century or more.
“Anytime there’s a one-second offset, we can let it go until it’s a minute or more and then change the time every century or more,” Tavella said.
The United States was among the countries that voted yes to pass the resolution.