leap second insertion

A leap second is an occasional adjustment added to Coordinated Universal Time (UTC) to keep our clocks aligned with Earth's slightly irregular rotation. Since Earth's rotation can vary due to factors like gravitational interactions and geological activity, our time measurements need periodic corrections. When Earth’s rotation slows slightly and the difference between atomic time and solar time gets too large, a leap second is inserted—usually on June 30 or December 31—by adding one second to that day. This ensures our clocks stay synchronized with the position of the Sun, maintaining accurate timekeeping for navigation, communication, and scientific purposes.