Why Did Scientists Spend 14 Years Staring at Clocks?

The atomic clocks ticked with nary a glitch for 14 straight years. Valentin Drull/Shutterstock

As anyone who's ever languished in a waiting room will attest, a clock doesn't tick faster when you stare at it.

In fact, time seems to be a thoroughly egalitarian concept. It keeps the same beat for all of us.

That's a crucial plank underpinning Einstein's theory of relativity — that the universe is its own clock, abiding by steady and unflinching rules. Neither time nor place is granted an exemption.

With everyone and everything in the universe playing by the same rules, it's much easier to accurately chart cosmic phenomena like the birth of a star or a planet's orbit.

The thing is the tiniest, almost imperceptible wobble in time could generate a vastly different outcome from what we might deduce using the laws of physics.

"The modifications might be very, very small," physicist Nicolas Yunes of Montana State University told Wired. "Everything we measure is approximate," he says. "If you're measuring distance with a ruler, you can only measure up to the accuracy of the ruler."

So how do you go about proving that time waits for no one?

How about staring at a clock for a very, very long time?

That's exactly what physicists from Colorado's National Institute of Standards and Technology (NIST) did.

The experiment — its findings were published this week in the journal Nature Physics — began back in November 1999 when the team rounded up 12 atomic clocks.

Close up of an atomic clock
For the experiment, atomic clocks were kept in a room that was rigidly controlled for temperature and humidity. karenfoleyphotography/Shutterstock

These clocks were selected because they're the most accurate in the world, but more importantly, there's an atom at their heart. The light the atom emits reveals how the nucleus and electrons are constantly swaying against, and away, from each other. That atomic ballet is mind-numbingly consistent, no matter how much time passes.

Essentially, it's a perfectly boring way to observe tiny identical actions over and over again.

"If the temperature changes more than 0.5 degrees, they'll get alarms to go fix it," lead researcher Bijunath Patla noted. "Most of it is automated, but someone watches it all the time, and someone carries a beeper."

With every possible variable accounted for, that left researchers with nothing but time. And, even space. After all, the clocks were on Earth — and Earth orbits the sun. That meant they occupied a different space in the universe with every tick.

The experiment ended 14 years — or 450 million seconds — later. No matter where they were in time and space, the clocks didn't skip a beat. But the scientists' hearts did. The theory of relativity — that the universe holds true to a fixed set of rules — held true. That's not to say, of course, these results prove Einstein's theory beyond a doubt. Even 14 years of straight clock-watching is really just a speck of time on the cosmic scale, and far too brief to draw a definitive conclusion.

But, at least in this specific part of the universe, we can say — and with apologies to the Rolling Stones — time is on no one's side.