For over five decades, humanity has utilized “leap seconds” to ensure our timepieces stay synchronized with the Earth’s rotation.
Recently, a global timekeeping organization in France decided to eliminate leap seconds, allowing the clocks to gradually drift out of sync by up to an hour over centuries or even millennia.
The precise atomic time we rely on, established in the 1950s through tracking atomic vibrations, slightly differs from solar time, tied to the sun’s position relative to a specific Earth location due to the planet’s slowing rotation.
Introduced in 1972, the leap second corrected this discrepancy by adding ten seconds immediately, according to Scott Beattie, the leader of the frequency and time team at Canada’s National Research Council’s Metrology Research Centre.
Since then, the International Earth Rotation and Reference Systems Service has monitored the gap between solar and atomic time to decide when to insert an extra second.
Leap seconds have been added 27 times, most recently in 2016, either at the end of December or June.
Scott Beattie, lead of the frequency and time team at the National Research Council of Canada’s Metrology Research Centre, notes the increasing complexity of managing leap seconds as many systems depend on precise timekeeping. (National Research Council Canada)
The absence of these adjustments would go unnoticed within our lifetimes. However, in the long run, Beattie warns of a scenario where daytime brightness coincides with midnight and darkness with noon.
Similar to leap years, which add a day to February every four years to align with the seasons, leap seconds maintain calendar accuracy due to the Earth’s orbit taking around 365¼ days around the sun.
Without these corrections, extreme shifts in weather patterns could occur, flipping hot months to winter and cold months to summer, Beattie explains.
Why the Change?
The consensus is growing that leap seconds pose more challenges than benefits.
Beattie emphasizes the global inclination to eliminate these disruptive leap seconds.
Managing the small adjustments presents difficulties for tech and telecom industries relying on precise time