Patricia Whitelock
Perhaps it’s because we have 10 fingers and work on a decimal system that numbers and intervals of time like 10 and decade, 100 and century or 1 000 and millennium seem to have such significance.
This probably explains the interest in the beginning of the new millennium, but not the controversy associated with its exact date – one which seems to have accompanied the start of every new century as far back as we have records.
Traditionally astronomers, like myself, are consulted about the calendar, because the length of our day and our year are determined by astronomical events. A day is the time it takes the earth to rotate on its axis, and a year is the time it takes the earth to go around the sun – at least that’s a year in the Western calendar with which most of us are familiar.
Since the time of Julius Caesar, our calendar has included leap years to allow for the fact that our year is a bit longer than 365 days. But the start of the modern Western calendar, year number one, has nothing to do with astronomy and neither has the start of the new millennium.
Why should it be controversial? Everyone knows that the next millennium begins on January 1 2000, right? Well, maybe or maybe not. You actually do have some choice in this, depending on how you look at it and what you’re interested in.
First, there are about 40 different calendars in use around the world and several even in South Africa. For example, on January 1 2000, the Indian (saka) year will be 1921, the Islamic (hijra) year 1420 and the Jewish (AM) year 5760. Most calendars, like the Christian one, start with a significant event – in the case of the Muslim calendar the flight of the prophet from Mecca (hijra) sets the beginning.
If you can survive the confusion of using 40 calendars simultaneously, you could have a new millennium every 20 to 30 years. Of course, the date on which the year changes is different for each of these systems, and even Christian calendars have used a variety of days for the start of the New Year.
But what if we just used the standard Western calendar, often called the Gregorian calendar after Pope Gregory XIII, with which most of us are familiar? Surely then the new millennium must begin on January 1 2000? Not necessarily. To understand why we need to look at history and our system of numbering years.
Early in the sixth century an astronomer and monk named Denys the Little (or more properly Dionysius Exiguus) decided that the counting of years should be changed to recognise the significance of the birth of Christ. He determined that Christ was born on December 25, a year before what we now call 1AD, in the year we call 1BC. The Gregorian calendar counts years from January 1 1AD, and 2 000 years, or two millennia, will have passed on January 1 2001.
That’s why many people say the new millennium starts in 2001 rather than 2000. Interestingly this problem stems from the fact that Denys the Little didn’t include a year zero, not too surprising given that nobody west of India seems to have used the idea of zero until 200 years later.
So the question of when the new millennium starts depends on what you mean. If you want to celebrate the beginning of the 2 000th year of the calendar of Dionysius Exiguus, the date to use is January 1 2000. If you like the idea of celebrating the 2 000th anniversary of the start of our calendar, you’ll have to wait until January 1 2001. The choice is yours, but I intend to play it safe and celebrate them both.
That seems simple enough, but Denys the Little didn’t have unlimited historical resources, and made errors in his calculations. The average date calculated by early Christian authors places Jesus’s birth in 3BC or 4BC, and they probably had access to more historical records on the reigns of Herod and Augustus than we do.
Modern scholars place Jesus’s birth in 6BC or 7BC. He must have arrived well before the death of Herod, which was certainly no later than 1BC and is usually given as 4BC. So if you want to celebrate Christ’s 2 000th birthday, you’re probably too late.
Dr Patricia Whitelock is deputy director of the South African Astronomical Observatory