Most precise clock to watch tiniest ever time dilations
Baku, Aug 24 (AZERTAC). If you follow scientific developments as if they were football games, this would be a good time to cheer "Tick-tick-tick-tick! Tick-tick-tick-tick! Go, clock, go!"
The reason for such enthusiasm? Researchers have released a study in the journal Science describing what they believe is the world's most precise clock.
You'd never need this level of precision for getting to work on time, but the clock could be used for scientific exploration and technological advancements in areas such as navigation systems, said study co-author Andrew Ludlow, researcher at the National Institute of Standards and Technology in Boulder, Colorado.
The rate of ticking of this timepiece -- known informally (and awkwardly) as the ytterbium optical lattice clock -- does not change by more than one part in 10^18, Ludlow said. In other words, if there is any variation in how a second is measured, it would be in about the 18th decimal place.
"The ytterbium optical lattice clock has demonstrated a groundbreaking, new level of clock stability," he said. "One could say that this is like measuring time over a hundred years to a precision of several nanoseconds."
In order to understand what's so special about this table-sized clock, it helps to have a little background:
Inside a clock is a mechanism that changes in some regular way, called an oscillator. Imagine, for example, a grandfather clock, whose pendulum swings back and forth denoting time. In a wrist watch there is often a crystal with an electrically oscillating signal.
A particular number of "back and forths" corresponds to one second.
An atomic clock makes use of an electromagnetic signal -- in other words, light emitted at an exact, known frequency. At the core of the system, there is an atom. The light is used to excite an electron in the atom.
In this model, the excitation and de-excitation of an electron corresponds to a pendulum swinging right to left, but in an atomic clock, the "tick" denotes an unimaginably tiny fraction of a second.
The current gold standard for time is the cesium clock, a type of atomic clock that an international body of experts has used to define what is the unit of one second: About 9.19 billion oscillations. In this clock, a microwave light source is used to excite electrons in cesium atoms.
But the new atomic clock at NIST, described in the Science study, uses a different element: Ytterbium, atomic number 70. Optical light -- specifically, yellow light from a laser with a wavelength of 578 nanometers -- is used to excite the electrons of ytterbium atoms.
Whereas scientists talk about billions of oscillations per second in the cesium clock, oscillations per second in the ytterbium clock approach one quadrillion per second, Ludlow said.
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