Inception of Leap Seconds

 Leap seconds were introduced in 1972 to align UTC with Earth's rotation, which changes slightly over time due to gravitational forces

Definition of a Leap Second

A leap second is an adjustment of one second, either added or subtracted, to UTC to keep clocks in sync with the Earth's rotation, effectively creating a minute with 61 seconds​

Occurrence and Timing

Leap seconds are added either on June 30th or December 31st, traditionally at the end of the day, just before midnight, to maintain timekeeping accuracy

The Need for Adjustment

The average day is about 0.002 seconds longer than 24 hours, necessitating the addition of a leap second approximately every 1.5 years

Leap Seconds Added So Far

 Since the system's inception, 27 leap seconds have been added to UTC, making it currently 37 seconds behind International Atomic Time (TAI)

Potential for Negative Leap Seconds

 While all leap seconds so far have been positive, there's a possibility for negative leap seconds if Earth's rotation accelerates, which would mean skipping a second

Growing Days

The length of a day is increasing by approximately two-thousandths of a second per century, meaning that days are slowly getting longer over time​

Debate over Continuation

There's an ongoing debate in the scientific community about whether to continue the practice of adding leap seconds, with arguments for and against based on their impact on timekeeping and technology​

Future of Leap Seconds

The World Radiocommunication Assembly postponed the decision to abolish leap seconds to 2023, with no final decision yet

Leap Second Impact

While necessary for astronomical and navigational accuracy, leap seconds can cause disruptions in systems tightly synchronized with UTC, such as in air-traffic control and satellite navigation