One Decade Ends, Another Begins

In 1999 and probably even before, there began a heated debate as to whether or not the millennium and the century came to an end on December 31st, 1999 or whether it should be celebrated on December 31st, 2000.  Some held to the belief that since the calendar began in 1 AD and there was no 0 AD that the century and millennium ended on December 31st 2000.  While common human instincts would lead others to say that the century ended in 1999.  In this case, if we were to follow the Gregorian Calendar, then the 20th century ended on 31-Dec-2000, and the 21st Century began on 1-Jan-2001...as did the 2nd Millennium.  The rationale being that the 1st century began on 1-Jan-1 and ended on 31-Dec-100 (100 Years).  Following this tradition all the way through...the 19th Century ended on 31-Dec-1900 and the 20th Century began on 1-Jan-1901.

But, wait there's more...

Now let's take a different route...let's use the Astronomical way of tracking years.  In Astronomical terms, 1 BC is considered Year 0...so astronomically the transition from BC to AD went -0002 (3 BC), -0001 (2 BC), 0000 (1 BC), 0001 (1 AD), 0002 (2 AD), etc...The ISO 8601 standard of date/time tracking is used in Astronomy.

So, the 1st Century AD started in 1-Jan-0000 (1 BC) and ended 31-Dec-0099 (99 AD)...Awesome!

But, more appropriately, it is sometimes just held that the 1st Century AD started on 1-Jan-1 AD and ended on 31-Dec-99 AD...and the 2nd Century began on 1-Jan-100 and ended on 31-Dec-199...etc.  If you consider 1 BC as Year 0 then this would make more sense to you.

This little bit of historical data overload is just a demonstration of where the whole debate stems from.  It's really just a little bit subjective...and if you're anything like me...you solved the dilemma by celebrating the new Millennium/Century on 1-1-00 AND 1-1-01...Just to be safe!

But, what does this have to do with decades?...Absolutely nothing!

A decade is defined as a period of 10 years, and in common use can be used as a measure for any 10 year period...but most commonly it is based on the tens digits of the years which you wish to track...ie the roaring 20s (1920-1929)...the 1960s (1960-1969)...etc.

So, although the end of the century and millenia is up to interpretation, there is no real argument when stating that the 90s ended on 31-Dec-1999 and the 00s began on 1-Jan-2000

Therefore there should be no argument that the 00s will end tonight 31-Dec-2009 at 11:59:59...and equally no argument that the new decade (the 10s) will begin at 0:00 on 1-Jan-2010.

Happy New Year and Happy New Decade to Everyone!!!

Peace
G