Today, February 29th, is Leap Day. Leap Day is the extra day inserted into the year to keep our calendar from getting out of whack with the seasons. Without Leap Day, Christmas and Groundhog Day would soon be crashing into each other. And I really don’t think Santa and Punxsutawney Phil are compatible.

The trouble started soon after the Big Bang, when the planets didn’t get into their correct orbits around the sun. Pesky Venus was its usual pushy self, shoving its way past Earth so it would be second instead of third. This caused orbital perturbations of such magnitude that Earth’s year was no longer an even multiple of its day. What a pain! (For more on this spacey topic, pre-order your personal copy of “Joe’s Guide to Celestial Mechanics, and Other Fairy Tales.”)

These solar system shenanigans meant that at the end of a year, there was some day left over that no one knew what to do with. Julius Caesar solved this enigma in 45 BC, by realizing he could keep the partial day in his pocket each year until he had saved one complete day. He could then insert it into the new calendar he had invented, which he somewhat self-centeredly called the Julian Calendar. This was right after he had invented Caesar salad. 

Unfortunately for Julius, he never got to collect an entire day, as he was assassinated the following year (44 BC – evidently they counted backwards in those days). Conspiracy theorists suspected calendar reactionaries were the culprits. Leap day, of course, comes only every fourth year, unless the year is not divisible by 400, or when sounded as “A” as in neighbor and weigh. So we won’t see another Leap Day for a while, unless Venus decides to go back where she belongs – well, never mind. That probably won’t happen.

Leap Day at one time was known as Bissextus, which, despite its racy sound, means “double sixth.” You see, (or if you don’t, just look over here) they used to add the extra day after March 6, instead of the end of February, and didn’t even dignify it with a number. There was a day-long pause between March 6 and March 7. In modern times, we are much more sympathetic to Leap Day’s feelings.

We can celebrate Leap Day in many ways. A recent scientific survey, conducted in my head, showed that a majority of Americans would like to celebrate by inviting all of the presidential candidates to take a flying leap at the moon. Now, there’s a popular application of celestial mechanics.

To make Leap Day feel welcome, and to show our appreciation, let’s wax poetic before the day wanes:

Ode to Leap Day

February’s lingering, keeping March at bay,

It’s the strangest of times, known as Leap Day.

As a day in June, what is so rare?

To Feb 29, none can compare.

Leap Day, you see, is the rarest of phantoms,

For it comes but once every four annums.

Blue moons we’re practically tripping over

Compared to Leap Day, that erratic rover.

So leap to your feet, indulge in some antics,

To honor this fluke of celestial mechanics.

Guzzle some nectar, kiss and hug someone dear,

Till the year Twenty Twenty, this day won’t reappear!

Tags: Bissextus February 29 Julius Caesar Leap Day Leap Year