Why is December 31st, 2016 going to be longer than other days? Because there is one extra second scheduled in the day—a leap second. It also happened June 30th, 2015. The International Earth Rotation and Reference Systems Service adds a leap second every few years to keep the clocks we use to measure official time and the speed of Earth's rotation in sync. But why do we need to do this? And what kind of problems could result?
Click here to read more about the leap second
