THE MAY MORNING WAS WINDY AND RAW

THE MAY MORNING WAS WINDY AND RAW, YET THE CROWD OUTSIDE the Royal Observatory in Greenwich. England. Southeast of London. Seemed oblivious to the weather. As the gates opened, people surged through and headed for the museum’s premier attraction: the prime meridian, an imaginary line that circles the globe north-south, marking zero degrees longitude-(000⁰00^’00^” ). It is the place where East meets West; the place where time begins.

Once inside the courtyard, excited schoolchildren hopped back and forth across a plate-glass strip set into the cobblestones: the line marking the meridian. The youngsters giggled and called to their teachers: “Over here, Miss Kemp.Look. I’m in the Eastern Hemisphere. Wait, look again. I’m in the West.”

Mounted on the brick building behind them, near a banner heralding “2/0⁰0^’00^’’, The Millennium Starts Here.” The observatory’s digital clock counted down to midnight, December 31,1999. Watching the milliseconds flash by with lightning speed, we felt an overwhelming sensation of time slipping away as we were propelled inexorably toward the year 2000.

Even those of us who can’t journey to Greenwich for the millennial festivities can become time travelers here at home.

A new permanent exhibition at the Smithsonian’s National Museum of American History’ “On Time,”explores the changing ways Americans have measured, used and thought about the passage of days, hours, and minutes during the past 300 years. The epicenter of world time , though , remains on that legendary meridian in Greenwich. “It isn,t only children who find this place fascinating,” observed Jonathan Betts, curator of horology at the Royal Observatory, as we watched a group of Japanese businessmen line up to be photographed astride zero degrees longitude. Just then a schoolgirl held out a camera to Betts. “Could you take a photo of me and my chum?” she asked shyly, oblivious of Betts ‘ august role as a presiding authority in the realm of Greenwich Mean Time (GMT). Betts grinned and obligingly snapped a picture of the two firls, who then scurried off to a nearby vending machine which, in exchange for a British pound (about $1.60), delivered an official certificate noting the precise moment, to aone-hundreth of a second, that they had visited the historic spot. “Being mice to visitors is part of my job,” chortled Betts, an amiable 44 year-old who lives and breathes clocks and is one of the best-known and most respected horologists in the world today.

Betts pointed out that the beginning of the year 2000 is not the real millennium, but merely the beginning of the countdown to it. “Say I owe you twenty dollars and pay you back a dollar at a time,” he explained. ‘You don’t consider the debt settled until I’ve given you the last penny of the twentieth dollar. By the same token, we won’t have completed the millennium until we’ve finished the 2,000^th year – and that doesn’t happen until December 31, 2000.” But the Royal Observatory has no intention of raining on the millennium parade. “when the zeros come,” said Betts, “we’re going to be celebrating ahead of schedule along with everyone else. It would be rather churlish not to, wouldn’t it?”

Inside the observatory, designed by Sir Christopher Wren in 1675, Betts presides over a collection of some 1.5000 timepieces, the crown jewel of this is H4, considering by many the most famous clock in the world, and which Betts has dubbed the “Mona Lisa of Horology.” The H stands for the John Harrison who, in 1759, constructed the clock, the first timepiece able to keep sufficiently precise time at sea. The invention allowed British sailors to measure longitude accurately when out of sight of land, a feat that changed the course of history and forever influenced world trade, exploration and war.

Long before Harrison devised his historic clock, people had grappled with ways to measure time. Cavemen began with big chunks of it, based on the movements of the sun and mood and the changing seasons. A 30,000-year-old-bone, discovered in the Dordogne rejoin of southwestern France, may be one of the earliest attempts at lunar timekeeping. Carved groves in the bone appear to represent the moon’s travels over a period of several months.
Many thousands of years passed before people measured time more precisely, not only in months, weeks, and days, but in smaller slices, chopping days into hours, then minutes, seconds, and ultimately-or at least so far-picoseconds (trillionths of a second). To grasp how small a measure of time is, light, which zips along at 186, 347 miles per second-fast enough to reach the moon from the earth in just 1.2 seconds-travels only one-hundredth of an inch in a picosecond.