Leap Year !

Well, it is February 29th - We don't have a lot of these, and here's why:
 

1. The earth does not orbit the sun in exactly 365 days.   In fact, it is a little less than 365 1/4 days.
2.  Julius Caesar (Roman Emperor) with the help of his astronomer came up with the solution of having a 365 day year (previously 355 days with an extra 22 day month every 2 years - a wee bit complicated), with an extra day every four years.
3. Remember, however, that the earth does not quite orbit in 365 1/4 days but slightly less. So Pope Gregory XIII and his astronomers made an adjustment in the 1500's. A year that is divisible by 100 but not 400 is not a leap year. So, the year 2100 will not be a leap year.
4. One more little tidbit is that February used to have 30 days; however, during the reign of Roman Emperor Caesar Augustus - he did not like that his namesake month (August) had only 29 days, whereas Julius Caesar's namesake month (July) had 31. So, he took a couple of days from February to make August the same as July! (Hence, the two months in a row with 31 days!)   Ahhhh, Ego - thy name is many and varied.

Usually, if the year is divisible by 4 - it is a leap year (noting the exception above).

One final note - just because you are born on February 29th does not mean you only age 1 year for every 4 years compared to everyone else!
Yes, a couple of students did inquire about this.