Today marks Leap Day, which as we all know only rolls around once every four years.
February 29 marks an extra day on our calendar, meaning this year is actually 366 days long, instead of the regular 365.
But why does a leap year exist?
They exist because while the world follows a 365-day Gregorian calendar, it actually takes the planet a little bit more than a year to orbit the sun.
According to NASA, it takes Earth 365 days, 5 hours, 48 minutes and 46 seconds to orbit the sun, and while that is rounded down to the 365 days we recognise as a typical year, those nearly six extra hours don’t disappear.
Therefore, a leap year is added to make up the difference.
Without leap days, in 100 years, calendars would reportedly be 24 days off, and in 700 years, Northern Hemisphere summers would begin in December.
So why does Leap Day fall in February?
Ben Gold, a professor of Astronomy and Physics at Hamline University in Minnesota, USA, told CBS Minnesota in 2016 that this is because of the Ancient Romans.
He said: “It’s mostly that the Romans didn’t really like February very much.”
At the time, in the 8th century BC, the calendar was just 10 months long, with the Romans considering winter to be all one period not divided into months.
Eventually, the Romans established January and February. February, the final month, had the fewest days.
The professor continued to explain that Julius Caesar then adjusted the calendar to line it up with the sun, adding the leap day via decree.
In 1582, Pope Gregory XIII adopted the Gregorian calendar, which we now use, and specified that all years that can be divided by four are leap years, with the exception of century years, which would have to be divisible by 400 to be considered leap years — so while 2000 was a leap year, 2100 and 2200 will not be.
In the 1700s, British law designated February 29 as Leap Day.
What happens if you are born on a Leap Day?
According to the History Channel, at least 5 million people celebrate their birthday on leap day.
Your odds of being born on February 29 are one-in-1,461.
Many people born on a leap day will celebrate their birthday on either February 28 or March 1.
