Debate Over When the 21st Century's First Quarter Ends

Mathematicians highlight differing definitions of century timelines as 2024 concludes.

The question of whether a quarter of the 21st century has passed hinges on varying interpretations of when the century began.
Many celebrated the new millennium on January 1, 2000, but mathematically, the 21st century started on January 1, 2001, due to the absence of a year zero in the Gregorian calendar.
If the 21st century began in 2000, 25 years will have elapsed by December 31, 2024; if it began in 2001, the quarter-century mark will occur at the end of 2025.
Mathematician Daniel Potts from TU Chemnitz calculated that, based on the exact number of days in a century, a quarter-century technically ends on the morning of December 31, 2024.
The debate underscores the complexity of time measurement and how historical conventions influence perceptions of milestones.