I’ve been a photographer for a long time, and on the Fourth of July most years anyone that knows me probably can guess one thing I’m doing that day. Like most citizens of the U.S.A I will be laying out my blanket somewhere to take in an amazing fireworks show. Unlike many Americans I will be lugging around pounds of photography equipment in the hopes to capture that one shot that truly say America.

We take the calendar for granted. We all manage our lives hour by hour, day by day, week by week, but we seldom consider the truly strange thing that the measurement of time actually is. For example: do you know how Election Day is reckoned? How about knowing when Easter will occur, and why it will happen when it happens?

You know, the day isn’t even as long as you think it is; it’s shorter by four minutes. This adds up to a quarter day every year, or a whole day every four. More or less. Kind of. Maybe.

To reconcile this incongruity, every fourth year (except in certain centuries) is a Leap Year. Why a “leap” year? Well, because in common years, the advancement of the calendar puts fixed-date holidays on subsequent weekdays each year, i.e., Christmas is on Tuesday, then Wednesday the next year, then Thursday, etc. In leap years, Christmas would “leap” over Thursday to Friday.