An event just for Leap Year 2016, at the Ori in Springwood. Come and join us for a drink and celebrate this opportunity for filling an elusive day in the caching calendar.
Location: Orient Hotel, 112 Macquarie Road, Springwood
Date: 29 February 2016
Time: 8:30 to 9:30pm
What’s so special about a leap year? Apart from the obvious (getting a new souvenir from groundspeak for attending an event today), we need leap years to keep our Gregorian calendar in alignment with the Earth’s rotation around the Sun.
It takes the Earth 365 days, 5 hours, 48 minutes and 46 seconds to circle once around the Sun. This is called a tropical year. But, the Gregorian calendar only has 365 days in a year. So, if we don’t add in an extra day nearly every 4 years, we would lose almost six hours off our calendar every year. After 100 years, our calendar would be out by around 24 days.
There are three criteria in the Gregorian calendar to identify a leap year:
- the year is evenly divisible by 4;
- if the year can be evenly divided by 100, it is NOT a leap year, unless;
- the year is also evenly divisible by 400.
So 2000 was a leap year, but 2100 will not be a leap year. Although the Gregorian calendar was decreed in 1582, it was not adopted by most Protestant and Orthodox countries until much later, eg Britain only adopted it in 1752. The year 2000 was therefore the first time in many parts of the world that the third criterion was used to determine that a year was a leap year.
Some more leap year trivia – leap years were introduced in the Roman Empire by Julius Caesar. But there was only one leap rule in the Julian calendar – any year evenly divisible by 4 is a leap year. This resulted in too many leap years, as the Earth’s rotation is slightly under 365 days and 6 hours. It only took 1,500 years to correct this, with the introduction of the Gregorian calendar.