When is 21st century begin

His arguments are supported by irrelevant historical asides and illustrated by graphs that he heroically misinterprets. Like most of the heretics, he seems to be hung up on zero as a starting point. The 99th year then begins at 98 and runs until the beginning of The th year begins at 99 and runs until the end of 99 or the beginning of the th year. This makes years. There are years between zero and , not years. The th year does not run to the end of 99, it runs to the end of , up to How could it run to its own beginning?

A century is complete years. So the first century ended on Dec. That took it to the first day of the second century, Jan. And so on to Jan.

Of course. And that is the custom that will set off riotous celebrations on the night of Dec. In fact, Fiji is right up against the degree meridian of longitude. But that is not the final word either. The dateline has long had an eastward bulge beyond the degree line, including the South Pacific island of Tonga, situated in a later time zone.

But Kiribati, a wide-spread island nation split by the date line, with a different date in each half, has announced a spectacular relocation of the date line eastward around their boundary. Now Kiribati's Christmas Island will see the new millennium an hour before Tonga. Personally I hope to go to bed early and find a new millennium waiting for me when I awake. Sign up for our email newsletter. Already a subscriber?

Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. The editors of Scientific American offer this explanation: Years in the most popular calendar used today, the Gregorian calendar, are counted from the year A.

Get smart. Sign Up. Support science journalism. But I do understand our number system as well. For example, our ages. If someone is born on April 2, , their first birthday is held on April 2, On that date, they're actually starting to live in their SECOND year, not their first year, since they just lived through their first year. I actually try not to think about it too much or it'll blow my mind! Skip to main content. You are here Editors' Musings. When Does the New Decade Start? Is the Start of a New Decade?

By Catherine Boeckmann. December 30, About This Blog. Related Articles Calendar. Tags decade.