Humberside Geologist Online

Millennium by Mike Horne

Why is the year 2000 important?

Presumably it is important to Christians because they believe that it represents 2000 years since the birth of Christ, which is celebrated on December 25th or January 6th (never on New Years Day). The Christian way of numbering the years was invented in 531 CE by Dionysius. He used the Roman way of counting, which does not have a zero, so the years were counted from year one. January 1st 2000 therefore represents 2000 years after the end of 2 BCE. However, the Christian Gospels claim that Jesus was born during the reign of King Herod who died in 4 BCE, so the 2000th anniversary of the birth of Jesus should have been celebrated in or before 1997 CE.

The obsession with tens, hundreds and thousands as anniversaries is merely because our system of counting is based on the numbers of fingers and thumbs (digits) on our hands. If Tyrannosaurus rex had invented a system of counting things would be different!

The year 2000 or Y2K was important to computer programmers. When computers were first developed they had very little memory, so writing compact programs was crucial. Programmers could save crucial memory by using only 2 integers to represent the year. But later forgot to change things as time went on and the 'millennium' approached. But as we now know, the world as we know it did not come to an end because of this problem.

Is there any reason that the year 2000 CE should be important to geologists? Well we usually look back at time rather than forward and so our dates are given in years Before Present (BP). Experts using radiocarbon dating eventually realised that the "Present" was not a fixed point in time, so they defined it as 1950 CE. So I suppose for a geologist this year (2000 CE) should be referred to as 49 After Present. Also, we geologists realise that a year, based on the orbit of the Earth around the Sun is not a constant number of days and has decreased over geological time as the velocity of the Earth has slowed.

Note - CE and BCE refer to Common Era, and Before Common Era, and are equivalent to the Christian AD (anno Domini meaning "the year of our Lord") and BC (Before Christ).

Further reading (updated August 2002):

Duncan D E 1998. The calendar. 360 pp, Fourth Estate, London.

Gould S J 1993. Fall in the house of Ussher. Natural History 100, issue 11, 12-20.

Gould S J 1996. Dousing Diminutive Dennis's Debate (or DDDD = 2000). Chapter 2, pp 11-23 ofDinosaur in a Haystack. 480pp, Penguin Books Ltd., London. (Previously published in Natural History)

Gould S J 2000. The First Day of the Rest of Our Life. Or, What I did on January 1, 2000. Natural History 4/00, 32-38 &82-86.

Lemon R R, 1990. Principles of stratigraphy. 559 pp, Merrill Publishing Company, Columbus, OH.

(c) Hull Geological Society 1999 + 2001