Researchers at the National Institute of Standards and Technology have invented the world's most precise atomic clock, according to a recently-published study in Science. The new clock, referred to as a ytterbium optical lattice clock, can measure a second to the precision of one part in 1018. Put one way, that means it'll measure the second exactly the same up to the eighteenth decimal place. Put another way, it means that if you started one of these clocks at the big bang, it would be no more than one second off right now.
The clock isn't exactly going to have much commercial use, at least not for everyday citizens who use their timepieces to be punctual for appointments and to wake up in the morning; one ytterbium clock is about the size of a dining room, and they would cost half a million dollars to reproduce.
Nonetheless, for those in the scientific community, the more accurate readings could provide invaluable in global positioning systems (GPS), navigation and communication systems, and in testing Einstein's theory of relativity, which states that time behaves differently dependent on gravitational force. Unfortunately, the mechanical functions of regular clock also behaves differently because of gravitational force, and so an accurate atomic clock who prove invaluable in further studies.
Generally speaking, clocks work by using an internal mechanism that changes at a regular rate, also known as an oscillator. In a grandfather clock, the oscillator is the pendulum; in a wristwatch, it's typically a crystal with an electrically oscillating signal.
With the atomic clock, an electromagnetic signal bombards an electron in a single atom at a predetermined frequency; the movement of that electron, then, is akin to the tiniest pendulum, swinging around its electron cloud in the tiniest of ticks.
Despite the large size and unwieldy price, it's impressive knowing that we can know measure a century or two down to the nanosecond. It certainly beats the sundials from five thousand years ago; this new version works, even when it's cloudy out.