This Thursday is February 29th. What would be the consequences of not having such a day every four years?
This Thursday will be February 29, so it is a leap year. Every four years, the year lasts one day longer, or 366 days. 2024 is a leap year as will be 2028, 2032, 2036, 2040… Why are they so necessary? To understand, we have to go back to ancient Rome. At the time, the calendar lasted 355 days because it was based on the cycles of the Moon and not those of the Sun. This being said, a problem quickly arose: this calendar corresponded less and less to the seasons. An additional month was then added every two years at the end of the year.
It was not until 45 BC that Julius Caesar introduced the solar calendar. As with the lunar, he again noticed a shift but this time it was less significant. This is why every four years, an extra day was added in February. As the Earth circles the sun in 365 and a quarter days, every four years, an extra day was needed to account for this extra quarter.
This organization of the calendar has remained for a long time but has nevertheless undergone some modifications. Notably, Pope Gregory XIII signed an ordinance in 1582 to remove leap years from centenaries, years divisible by 100 unless they were divisible by 400. This was an adjustment after the discovery that the Earth did not take exactly 365.25 days to go around the Sun but 365.24219 days. This is how the Gregorian calendar was born, with which we still operate today.
What would be the consequences of not having leap years? Each year, 5 hours, 48 ??minutes and a few seconds would be lost in relation to the Earth’s tour around the Sun and above all they would never be made up. The gap would end up being very significant. The concordance between the seasons and the calendar would gradually disappear. So winter weather might not correspond to the period between December and February and in a few hundred years July would occur in winter. Predictions of celestial events like solstices and equinoxes could also become difficult. And let’s think about agriculture: this could endanger crops. It would therefore be very difficult to do without it.