This Saturday, Feb. 29 is Leap Day. So, what does that mean?
Every four years, we add one day to our 365-day calendar to account for the timing of our not-so-exact trip around the sun. So why bother with Leap Day at all?
Here's what you need to know: One year equals one trip around the sun which equals almost 365 days. The number is actually closer to 365.2422 days. It may seem insignificant, but those extra decimals add up.
If we didn't have a Leap Day, we would miss nearly 6 hours every single year.
That would mean in 100 years, our calendar would be off by 24 days! That's why we have one extra day in February every four years. Problem solved, right? Not quite!
Even when we add Leap Day, our calendar is still off by roughly 11 minutes each year. After 100 years, our calendar would be off by 18 hours. So there needs to be something else in play to keep us on time.
Therefore, there's something called "Leap Year Hopscotch."
That means we actually skip a Leap Year if it falls at the start of a century unless that year is divisible by 400.
Here's an example: We skipped Leap Year in 1900, we did not skip it in the year 2000 (because it's divisible by 400), and we will skip Leap Year in 2100.
Is your head hurting yet? Wait, there's more.
By doing that math, our new yearly average times out to 365.2425 days.
However, even with Leap Day and "Hopscotch rules," the calendar is still off by nearly 26 seconds per year. But, at this rate it would take over 3,000 years for the calendar to be off by 1 day.
Maybe there will be a more precise system in place by then!