Most of the time, a year is made up of 365 days. But this year, just like 2012, and the year four years before that, has 366. And that vital extra day, a leap day, is (partly) what keeps our calendars in working order. As users of a solar calendar, we rely on the sun ...
Explainer: the science behind leap years and how they work
By Daniel Brown
25 Feb 2016