HOW DOES THE WORLD KEEP TIME?
Why the tick of timekeeping devices depends on hundreds of atomic oscillators positioned across the globe
WORDS LAURA MEARS
This container holds the caesium atoms that power an atomic clock
Have you ever wondered how the whole world stays in sync? We live in different time zones, but from New York to Melbourne, a second is always a second. That’s because everyone sets their local clocks using an internationally agreed standard called Coordinated Universal Time, also known as UTC. UTC is defined by an agency of the United Nations called the International Telecommunication Union. It’s based on two measurements: the ticking of hundreds of ultra-stable atomic clocks (International Atomic Time) and the rotation of the Earth (Universal Time).
Nations across the world set their local time by adding or subtracting from UTC depending on their position on the globe. UTC, or the world clock, has been around since the first day of the 1960s, shortly after Louis Essen built the first atomic clock. This precision timepiece promised to solve the centuries-old problem of second hands running too fast or too slow.