This year is a leap year. The exciting extra day, February 29, has a lot of significance attached to it whether it’s scientific value or just weird mythology about the day.
The reason for the leap years, which happen every four years, is understood to keep our man-made calendar and seasons where we expect them to be.
An animation made by James O’Donoghue, a planetary scientist at the Japanese space agency (JAXA), illustrates this necessity clearly.
“The way we do leap years is fairly messy looking, but I can’t think of a better way to handle them,” he told Business Insider. “We do it so our seasons don’t migrate over time.”
O’Donoghue explains in the video that although we measure 365 days a year, the Earth’s orbit around the sun is actually 365.242 days. The new animation shows how 2020 is actually 366 days long.
The use of a leap year makes sure that over time, our calendar doesn’t shift into different seasons because of the loss of days due to this discrepancy between our measurements and the scientific reality.
“One cannot simply add six hours to our year to fix this, because then the sun would rise six hours later the next day,” O’Donoghue said. “We could do it, but only if we don’t care that the 24-hour clock will cease relating to sunrise and sunset.”
So despite seeming a bit confusing, the addition of a leap day is actually the neatest way to deal with this issue.
Watch the animation, but keep in mind it’s representing seasons for the Northern Hemisphere: