Source: Freepik
Every year again … or rather every four years again.
The coming year 2024 has another day in store for us – February 29.
But what is a leap year and why does it exist?
It generally only occurs every four years, but there are some exceptions. In this blog post, you can find out more about the background to leap years, how they are calculated and why they exist at all.
Fact Check
To talk about the introduction of an additional day, the so-called leap day, we have to go way back in time. Gaius Julius Caesar introduced a calendar back in ancient Rome. We can no longer imagine life without a calendar. Whether to make appointments or to schedule our holidays. No generally valid calendar – unthinkable.
The lunar and solar cycles have always played a major role in the calculation of days. In 45 v. Ch., Gaius Julius Caesar created a coherent calendar.
As the earth takes exactly 365 days, five hours, 48 minutes, and 46 seconds to orbit the sun. This period is also known as the solar year and describes the time in which the earth passes through all the seasons. This means that the year always lacked just under six hours. These were compensated for by a leap day every four years. The so-called solar year was therefore almost reached and was now only 11 minutes and 14 seconds too fast each year. This calendar was called the “Julian calendar”.
Gregorian Calendar
This small discrepancy of 11 minutes and 14 seconds seems small at first but has led to extreme measures. Due to the minimal premature ending of the years, the calendar shifted by 10 days until the 16th century. Pope Gregory XIII finally tackled this problem and removed 10 days from the calendar in 1582. Although this made up for the shortfall and the calendar was intact again, the fixed days were shifted as a result.
This resulted in the rule to skip leap days at the turn of the century that are divisible by 100, such as the year 1900. However, there are exceptions: if the century year is divisible by 400, the year is considered a leap year, as was the case in 2000, for example. But even if the year can be divided by 4 without a remainder, it is a leap year.
Sounds complicated, but it ensures that the year is almost aligned with the solar year. A year therefore has 365.2425 days and is therefore only half a minute longer than a solar year.
Looking to the future, this means that the Gregorian calendar will deviate from the natural solar year by one day in 3,300 years.
We must also bear in mind that without the leap year, the seasons would slowly but surely shift, so that after several hundred years, summer in the northern hemisphere would begin in December!
But why exactly in February? Well, February was already the shortest month back then. That’s why the decision was simply made to extend February by one day.
So, the coming year 2024 will bring us an extra 24 hours and perhaps even the long-awaited birthday on February 29 for some!
Responsible for the content of this article is Merrit Mielke.
Sources:
[1] ARD
[4] RUHR 24
[5] Deutschlandfunk
[6] Rheinische Post
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