When Was Year Zero?

I do not remember when I learned the difference between “counting numbers” and “whole numbers” but it was pretty early in elementary school. I learned that the numeral “0” was a place holder. I was young enough to have trouble with understanding that it didn’t really represent “nothing,” as I was to learn later when I found why division and multiplication by 0 is not an identity function. (If you multiply 1 no times, it is still 1, but if you multiply it by 0 it is 0. You cannot even divide it by 0 at all and have a defined meaning.) I did understand, however, that if you had something, some books, some apples, some amount of time, you used the counting numbers. I later learned that you could always divide a quantity of something by a number and still have a quantity of something. 1 year divided by 2 is 6 months or 0.5 years, not “no” years just because it is less than a year in length.

What does this have to do with anything? Simply this:

As the year 2010 began, I listened to television station after television station comment on the end of the first decade of the new century/millennium. I then started receiving requests from members of an organization that I serve as archivist for material to use to commemorate the switch from the first to the second decade. Although I was happy to comply, I caused some dismay when I pointed out that the event in question was yet to come.

You see, even if some monk or other source miscalculated the date of Christ’s birth, and even if there was some error when adjusting calendars later, the years we use for either C.E. or A.D. dates are based on the years of the life of Jesus (A.D. = Anno Domini = “year of the Lord,” more or less) from the point of time that was or is believed to be his date of birth. That word, “point” is important. There is, in theory, a point on a number line that may be labeled “0,” but there is no meaning to a stretch of that line as the “0th” segment. Anything to the right of that point until the point “1” is reached is the “1st” segment; or segment “1.” There is no segment “0.” The 10th segment comes between “9” and “10” and is not complete until “10” is passed and the 11th segment begins.

In terms of years, it works like this. If I was born, (and I was,) there is no point in time when I am “0” years old. When I was 6 months old, I was in year “1” of my life and was 0.5 years old. When I had my 49th birthday, I had completed 49 years and was in my 50th year, or “50”. It is not until I complete 50 years, and enter “51” that I have completed 5 decades.

In the same way, when we entered the year 2010, we entered the 2,010th year from the point, accurate or not, that we defined as the birth of Jesus. The “point,” not the “year.” (The idea that someone mistakenly left year “0” off the calendar is ridiculous. Year “0” would be the year that Jesus existed but did not exist. Philosophical and theological questions aside, for our purposes this does not enter the discussion.) It will not be until “2010” is completed that we will have completed 201 decades, or the 1st of the new century. We are still in that one. By the same token, the 21st century began in 2001, not 2000. (As an aside, the need to do calculations in standard numerals without the A.D., B.C., CE, BCE abbreviations has created an astronomical numbering system that uses a year “0” and negative numbers, but that is only for calculation purposes.)

So plan your celebrations, exhibits, and projects. I would be thrilled to help with the work from our archives, regardless of the year. But please, understand, the numeral “0” is not a number, and January 1, 2011 will start a new decade. Then let’s whoop it up!