Leap day balances the calendar

COLUMBUS (WCMH) — Leap day comes around once every four years to balance out Earth’s orbit around the sun, which takes 365.2421 days to complete a single revolution. The difference means Earth lags behind by nearly six hours.

A decision was made nearly 2,000 years ago to catch up every fourth year to account for the four quarter-days so that calendars matched Earth’s position. Adding a leap day was conceived by Julius Caesar, when he was the leader of Rome, after a long military career.

However, the Catholic Church later determined that Easter was drifting by approximately 11 days, based on a comparison between lunar and solar cycles, according to History.com.

Pope Gregory XIII adapted the Western calendar employed by the Catholic Church (Gregorian calendar introduced in 1582) to resolve the 11-day discrepancy by removing centurial years not divisible by 400 (most recently 1900) from the classification of a Leap Year.