Leap year 2016 also gets a leap second

Be ready to have your New Year’s celebrations last a second longer. Literally. Timekeepers at the International Earth Rotation and Reference Systems Service (IERS), which keeps track of the world’s time, announced yesterday that an extra second will be added on December 31st. Around midnight, the clocks will read 11:59:60 instead of 11:59:59.

Leap seconds are added once in a while to ensure that the Coordinated Universal Time (UTC), the global measure of time, is adjusted to follow the variations in Earth’s rotation. Earth’s spin is not constant: the Moon’s gravitational pull and other factors like particularly strong earthquakes can affect how long our planet takes to rotate on its axis. Leap seconds ensure that atomic clocks can match...