Science behind Leap Days

With February 29th, or the Leap Day approaching, this is a great time to talk about the history and science behind Leap Day by none other than Neil DeGrasse Tyson.

Additionally, one of my favorites SciShow also does an incredible job of explaining the phenomenon.

Leap years exist due to the discrepancy between the calendar year and the solar year. Here’s a more detailed explanation below :

Solar Year vs Calendar Year: A solar year, the time it takes for Earth to orbit the Sun once, is approximately 365.24 days. However, our calendar year is exactly 365 days. This discrepancy of about 0.24 days, or 5 hours, 48 minutes, and 56 seconds, would cause the calendar to drift out of sync with the solar year over time.
Leap Year Rule: To correct this drift, we add an extra day, known as a leap day, to the calendar approximately every four years. This makes the year 366 days long.
Exceptions: Not every year divisible by 4 is a leap year. The rule is that if the year is divisible by 100 and not divisible by 400, the leap year is skipped. This adjustment ensures that the calendar year remains close to the actual solar year duration.
Effects: Without leap years, our calendar would get increasingly out of sync with the cosmos. For example, if we stopped using leap years, then in around 700 years the Northern Hemisphere’s summer would begin in December instead of June.

So, leap years are essential to keep our calendar in alignment with the Earth’s revolutions around the Sun. It’s all about catching up astronomically.!