Pope Gregory XIII

(Newser) - It's leap day, and scientist Chris Turner uses his extra time to muse in the New York Times on its origins. Julius Caesar came up with a plan—pinning the calendar to the Earth's circling of the sun—in 46 BC as a way to synchronize months with the seasons....

(Newser) - The Earth finished another rotation around the sun in 2007—just about. At midnight on December 31, it was actually about 400,000 miles short of where it had been a year before, and that annual shortfall is why we have leap years, explains the St. Louis Post-Dispatch. Leap years...