Today is Feb. 29, an extra special date that occurs only every four years but is incredibly important in how humans interact with Earth.
It may seem more novelty than necessity, but as J. Marshall Shepherd explains, if we didn’t have a leap year, our seasons would be all wonky and out of whack with the calendar.
Why? Well, it has to do with the Earth’s orbit around the sun, which our calendars say takes a neat and tidy 365 days.
But, it’s not all so perfectly timed. In reality, the Earth takes about 365.242199 days to go around the sun, Shepherd said. In addition, the time it takes Earth to revolve one time – a day – is actually just short of 24 hours.
It’s more like 23 hours, 56 minutes and 4 seconds.
“The calendar, without some type of periodic adjustment, would be out of ‘synch’ with the seasons by approximately one month every 125 years or so,” Marshall writes. “So once every four years, all of the extra time is added together to form a new day, February 29th.”
In June, we got an extra “leap” second, which according to NASA was needed as Earth’s rotation gradual slows down a bit because of a gravitational “tug of war” between the Earth, moon and the sun.
“Strictly speaking, a day lasts 86,400 seconds,” NASA says. “However, the mean solar day – the average length of a day, based on how long it takes Earth to rotate – is about 86,400.002 seconds long.”