Turn of the year Is a quarter of the 21st century already over?

SDA

30.12.2024 - 07:00

Mathematicians already pointed out at the end of the 1990s that it was actually too early to toast the new millennium at midnight on New Year's Eve '99. (archive picture)
Mathematicians already pointed out at the end of the 1990s that it was actually too early to toast the new millennium at midnight on New Year's Eve '99. (archive picture)
Keystone

25 years have passed since the turn of the year 1999/2000. So a quarter of a century has passed since the turn of the century and millennium - or has it? A journey into the realm of mathematics.

Keystone-SDA

Twenty-five years ago, it was the end of the 20th century. Almost everyone thought: The transition from December 31, 1999 to January 1, 2000 was the leap into a new century - and above all millennium. So now, 25 years later, a quarter of the 21st century is already over. But is that really the case?

Mathematicians already pointed out at the end of the 1990s that it was actually too early to toast the new millennium at midnight on New Year's Eve '99. The third millennium, and with it the 21st century, would not begin until January 1, 2001.

This is because there was never a year zero - the year 1 before Christ was followed by the year 1 after Christ. That is why the first 2000 years - the second millennium and also the 20th century - only ended on December 31, 2000 at midnight. Just as you only turn 30 after reaching the age of 30.

Billions celebrated the millennium change incorrectly

But there was already a lot of fanfare at the end of '99 with the motto: Millennium change. A new era. Understandable: the number 2000 simply had a seductive allure. Even in 1900, 1800 and so on, people were convinced that they were entering a new century.

It is well known that the 21st century has not developed much better than the 20th century, which is generally perceived as the century of horror - with two world wars, the Holocaust, the atomic bomb, the Cold War, environmental destruction and famine.

But the course of time between 1900 and 2000 also brought innovations such as radio, television, mass tourism, pop and the internet. Between 2000 and 2024 came achievements such as smartphones and streaming services, but also new wars, disasters and more climate change.

What a math professor says about the quarter-century problem

Back to the question of whether a quarter of the 21st century will have been completed by the end of 2024. What to do? Ask a math professor!

"So for everyone who celebrated the new millennium at midnight on December 31, 2000, a quarter of a century will not have passed by the end of 2024," says Daniel Potts from Chemnitz University of Technology. But that is likely to be very few people. "For all those who welcomed the new millennium on December 31, 1999, a quarter of a century will soon have passed," says Potts. "It depends on the definition of when a century begins."

Potts emphasizes that he has now simply assumed that a quarter of a century lasts exactly 25 years. "But how long is a year?" There are also leap years. The length of a century, and therefore the duration of a quarter of a century, also depends on how many leap years there are.

When exactly is the end of the first quarter of the century?

"A time span calculator tells me that there are exactly 36,525 days from January 1, 2000 to December 31, 2099. Then a quarter of a century will be over after 9,131.25 days." On December 31, 2024, however, 9,132 days have already passed. "So at midnight, there are now three quarters of a day too many." So mathematically speaking, we should or could celebrate the end of the first quarter of the 21st century at 6.00 a.m. on New Year's Eve. Professor Potts: "I don't think even mathematicians do this."