Today — the 29th day of February — comes around every four years.
Leap years are added to the calendar to keep it working properly. The 365 days of the annual calendar are meant to match up with the solar year, the time it takes the Earth to complete its orbit around the sun.
But the actual time it takes for the Earth to travel around the sun is a little longer, about 365 1/4 days. So the calendar and the solar year don’t precisely match, with the calendar year a shade shorter.
After a few years, those extra quarter days in the solar year begin to add up. After four years, for example, the four extra quarter days would make the calendar fall behind the solar year by about a day. Over a century, the difference between the solar year and the calendar year would become 25 days.
So every four years, a leap day is added to the calendar to let it catch up to the solar year.
Here are a few other fun facts about leap years:
• A year is a leap year if it is divisible by four, unless it is divisible by 100 and not by 400. This means that 2000 was a leap year, but 1900 and 1800 were not.
• Even-numbered decades have three leap years. For instance, 1980, 1984 and 1988. Odd decades have two leap years. For instance, 1992 and 1996.
• So, what were we talking about on this day four years ago, in 2008, during our last Leap Year? Among stories in The State newspaper: Spirit Airlines came into the Columbia market with a $7 fare; a nonscientific survey found Columbia residents cutting back on lottery tickets — but not $25 bottles of wine — as part of belt-tightening in the increasingly down economy; and Dick Vitale was catching flak about his pitch on why Bob Knight was a perfect fit to lead the USC men’s basketball team.