The surprising history behind leap year
By Brian Handwerk, National Geographic
It’s that time again: This Monday, Feb. 29, is a leap day, the calendar oddity that occurs (almost) every four years.
For centuries, trying to sync calendars with the length of the natural year caused confusion—until the concept of leap year provided a way to make up for lost time.
“It all comes down to the fact that the number of Earth’s revolutions about its own axis, or days, is not equal to or connected in any way to how long it takes for the Earth to get around the sun,” says John Lowe, leader of the National Institute of Standards and Technology (NIST)’s Time & Frequency Division.