American Scientist

We mark time differently than we measure distance. Although none of us is likely ever to have seen a new car odometer read 000000, we infer that that was indeed the reading when it was installed at the factory. As the car was driven from the assembly line to its parking lot, the wheels began to turn and the machine registered tenths, miles, tens of miles and so forth as they were reached. With dates we mark the days, months and years before they are completed, however, and so from the instant after midnight on New Year's Eve 1999, we by custom write the date as 01/01/00, even though it will be another 24 hours before that day is completed. And it will not be until midnight on 12/31/00 that the year 2000 is completed, and with it the 20th century. Y2K notwithstanding, the second millennium will really end not with a bang but a whimper.