In the past, 2012, forty-five years, from the moment when humanity decided to use atomic timekeeping for the most accurate measurement of time.In 1967, the International System of SI category ceased to be determined by astronomical time scales - in their place came a cesium frequency standard.That he was now a popular name - the atomic clock.The exact time that they allow you to define a tiny error in one second in three million years, they can be used as the standard time anywhere in the world.
little history
The idea to use the oscillations of the atoms to the precise measurement of time was first proposed in 1879 by the British physicist William Thomson.In the role of emitter atoms, this resonators scientists propose to use hydrogen.The first attempts to implement the idea in practice undertaken only in the 40s.twentieth century.And the world's first atomic clock work appeared in 1955 in the UK.Their creator was a British experimental physicist Dr Louis Essen.They worked the clock on the basis of oscillations of atoms of cesium-133 and thanks to them, scientists were finally able to measure time with much greater precision than it was before.The first unit of Essen permissible error is not more than one second for every one hundred years, but then repeatedly increased accuracy and error in the second may be coming up only 2-3 hundred million years.
atomic clock: the principle of operation
How it works clever "device"?As the generator of the resonant frequency atomic clock used the energy levels of molecules or atoms at the quantum level.Quantum mechanics establishes a relation of the "atomic nucleus - the electrons" with several discrete energy levels.If such a system will affect the electromagnetic field with a strictly defined frequency, there will be a transition of the system from low to high.It is also possible, and the reverse process: the transition of an atom from a higher level to the lowest, followed by radiation energy.These phenomena can monitor and record all the energy jumps, creating something like the oscillating circuit (also known as the atomic oscillator).Its resonant frequency corresponds to the energy difference between adjacent levels of the atoms of transition divided by Planck's constant.
This oscillation circuit has undeniable advantages compared to their mechanical and astronomical predecessors.For one of the atomic oscillator resonant frequency of the atoms of a substance is the same, which is not the pendulum and piezoelectric crystals.Besides, the atoms do not change over time, its properties and do not wear out.Therefore, atomic clocks are extremely accurate and virtually perpetual chronometer.
local time and modern technology
Telecommunication networks, satellite communications, GPS, NTP-server, electronic transactions on the stock exchange, online auctions, the procedure of buying tickets through the Internet - all these and many other events have long become part of ourlife.But if humanity has not invented the atomic clock, all this would simply not there.The precise time synchronization which minimizes any errors, delays and delay, allows a person to maximize the use of this precious irreplaceable resource, which can never have too much.
