This re-post springs forward from pondering time. At 2 AM my clock screamed 3 AM and I found myself calculating implications of time zone variances for friends and family. Happy Daylight Savings Day 🙂
Named after Pope Gregory XIII, the Gregorian calendar was introduced in 1582 – six years after the death of Luigi Lillio, Italian doctor, astronomer and philosopher credited with conceptualizing replacement of the Julian calendar. Julian, a hail to Julius Caesar, dominated the known world from 45 BC until the Gregorian revolution in 1582.
On average, Earth takes 365 days, 5 hours, 48 minutes and 45 seconds to complete one orbit around the Sun. Julian and Gregorian years are 365 days divided by 12 months. What to do with leftover hours, minutes and seconds – both embraced the leap year solution, vastly different implementation exposed Julian’s greatest flaw. Julian added an extra day to February every 4 years, a system resulting in a mathematical gain of one day every 128 years. That’s 3 days every 400 years, 28 days by the time Gregorian reform took hold in 1582 – close to…
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