Why Leap Seconds Can Cause Computer Glitches

In a recent video, Tom Scott gives an explanation for why leap seconds can cause computer glitches. Leap seconds are seconds of time added or removed from Coordinated Universal Time to account for the Earth’s irregular orbit. That can cause problems with computer programs that use Unix time, a simple measurement of the seconds that have passed since January 1, 1970.

A leap second will be added at 11:59:60 PM on June 20, 2015.