Did anyone notice that Dr. Mel said that Leap Years occur “ALMOST ever four years”? So, does that mean that Leap Years don’t occur EVERY fourth year?`The length of Earth’s solar year is not exactly 365 days 6 hours (365.25 days); it is actually 365 days 5 hours 48 minutes 46 seconds (365.24220 days). That 11 minutes 14 seconds discrepancy adds up over the years; in a century the calendar still creeps ahead by 18 hours 38 minutes (0.7766 of a day). After 400 years the calendar becomes approximately 3 days 2.5 hours out of sync. `When in the 16th century the Gregorian calendar (the one we use today) was devised, it was decided that to correct this 400 years discrepancy the “century years” not evenly divisible by 400 would not be Leap Years. Therefore the year 1600 was a Leap Year, but the years 1700, 1800, and 1900 were NOT Leap years, though they would have been in a strict 4-year cycle. The year 2000, however WAS a Leap Year. (We should have done some celebrating on Feb. 29, 2000 since it was a very unique day, coming only once every 400 years.)`There’s still that 2.5 hours discrepancy every 400 years, however. That will add up to a full day in about 3840 years. This is something our far descendants will have to deal with when the time comes.
Did anyone notice that Dr. Mel said that Leap Years occur “ALMOST ever four years”? So, does that mean that Leap Years don’t occur EVERY fourth year?`The length of Earth’s solar year is not exactly 365 days 6 hours (365.25 days); it is actually 365 days 5 hours 48 minutes 46 seconds (365.24220 days). That 11 minutes 14 seconds discrepancy adds up over the years; in a century the calendar still creeps ahead by 18 hours 38 minutes (0.7766 of a day). After 400 years the calendar becomes approximately 3 days 2.5 hours out of sync. `When in the 16th century the Gregorian calendar (the one we use today) was devised, it was decided that to correct this 400 years discrepancy the “century years” not evenly divisible by 400 would not be Leap Years. Therefore the year 1600 was a Leap Year, but the years 1700, 1800, and 1900 were NOT Leap years, though they would have been in a strict 4-year cycle. The year 2000, however WAS a Leap Year. (We should have done some celebrating on Feb. 29, 2000 since it was a very unique day, coming only once every 400 years.)`There’s still that 2.5 hours discrepancy every 400 years, however. That will add up to a full day in about 3840 years. This is something our far descendants will have to deal with when the time comes.