The Problem of Leap Seconds

Abstract

A leap second is an adjustment made periodically to keep UTC (Coordinated Universal Time) aligned with rotation of the Earth because the length of a day isn’t exactly 86,400 s. Without such an adjustment, in 5000 years, noon will be an hour off from the actual position of the sun in the sky. As I’ll explain, a better approach would be a once every 5000 years adjustment akin to the annual daylight adjustments to the clock.

As I’ll explain, the current practice of inserting seconds, in effect, redefines the minute. A minute whose length is uncertain causes unnecessary collateral damage. Applications that need the precision depend on finger-grained adjustments (such as UT1). Those applications cannot depend on civil time because, in practice, one cannot determine if a time stamp actually takes leap seconds into account. The best approach is to eliminate leap seconds so that those applications that don’t require the precision aren’t confused and those that do won’t be at risk due to the uncertainties in civil times.