When do the 3rd Millennium and the 21st Century start?


READ THIS FROM THE ROYAL OBSERVATORY AT GREENWICH:


A millennium is an interval of 1000 years and a century is an interval of 100 years. In the Gregorian Calendar, which we use, there is no year zero and the sequence of years near the start runs as follows; ..., 3BC, 2BC, 1BC, 1AD, 2AD, ... Because there is no year zero, the first year of the calendar ends at the end of the year named 1AD. By a similar argument 100 years will only have elapsed at the end of the year 100AD. Since 2000AD is the 2,000th year of the Christian calendar, it will be the last year of the Second Millennium. So the 3rd Millennium and the 21st Century will begin at the same moment, namely zero hours UTC (commonly known as GMT) on January 1st 2001. We have received a great deal of e-mail regarding the start of the 21st Century. It is interesting to note that this is not the first time that this controversy has arisen. The Times must have received many letters towards the end of 1799, since its editors felt moved to make the following comments about the beginning of the 19th Century:

"We have uniformly rejected all letters and declined all discussion upon the question of when the present century ends, as it is one of the most absurd that can engage the public attention, and we are astonished to find it has been the subject of so much dispute, since it appears plain. The present century will not terminate till January 1, 1801, unless it can be made out that 99 are 100... It is a silly, childish discussion, and only exposes the want of brains of those who maintain a contrary opinion to that we have stated"

The Times, 26 December 1799


AND THIS FROM THE US NAVAL OBSERVATORY:

Years of the Gregorian calendar, which is currently in use today, are counted from AD 1. Thus, the 1st century comprised the years AD 1 through AD 100. The second century began with AD 101 and continued through AD 200. By extrapolation we find that the 20th century comprises the years AD 1901-2000. Therefore, the 21st century will begin with 1 January 2001 and continue through 31 December 2100. Similarly, the 1st millennium comprised the years AD 1-1000. The 2nd millennium comprises the years AD 1001-2000. The 3rd millennium will begin with AD 2001 and continue through AD 3000.

AND THIS FROM THE WHITE HOUSE:

White House Millennium Council

When is the Millennium? mil-len-ni-um (n). A span of one thousand years. According to the United States Naval Observatory, the nation's official time keeper, the end of the second millennium and the beginning of the third will be reached on January 1, 2001. This date is based on a calendar created in Rome, in 526 Anno Domini (A.D.), now recognized globally. Rather than starting with the year zero, the calendar begins with the date January 1, 1 A.D. Consequently, the next millennium is not officially reached until January 1, 2001. Despite this fact, much of the world is planning to celebrate on December 31, 1999, when the calendars flips to the year 2000. During the millennium year (January 1, 2000 to January 1, 2001), the White House will lead a national Millennium Program that will engage Americans in a wide variety of activities and initiatives designed to highlight our heritage and celebrate our creativity.


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days 'til the year 2001: The Start of the New Millennium.
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