What's inside your computer


How Do Atomic Clocks Work?

If time is crucial to you or yourshared location where one of the world's
office, consider investing in atomicfew of the world's atomic clocks
clocks so that everyone knows exactlyoperates. A low -frequency radio signal
what time it is and everyone has thebroadcasts the time from that location
same time. These are the most accurateto all atomic clocks within its range.
time keeping pieces you can get, andThere are currently approximately 200
more and more businesses are usingatomic clocks world-wide in sixty
atomic wall clocks to make sure thatcountries.
accurate time sheets and appointmentsIn the United States, most atomic clocks
are kept.used for home and offices are
But what are atomic clocks and why aresynchronized to the National Institutes
they so much more accurate than regularof Standards and Technology atomic clock
clocks? A standard clock, whetherin Boulder, Colorado. The other official
wind-up, electric or battery operated,atomic clock is at the U.S. Naval
counts time by the number of "ticks"Observatory in Washington, D.C. and is
that a resonator makes. The resonator isthe official time clock of the
the device that actually keeps track ofDepartment of Defense. Since both of
time. In most clocks the resonator isthese atomic clocks are within one
either a swinging pendulum or (insecond of each other over a million
digital clocks) oscillations in theyears of time, it is unlikely that time
power line (which is a bit different indisplayed on atomic wall clocks at the
the U.S. and in Europe).Pentagon will differ from the time
Atomic clocks also use a resonator, butdisplayed on an atomic clock in your
the resonator counts based on thehome office!
resonance frequency of atoms. ResonanceHow Do At-Home Clocks Get the
is the emission or absorption ofInformation from Master Atomic Clocks?
microwave electromagnetic radiation byGlobal positioning satellites (GPS) in
an atom. It is very regular, and nothe skies above us transmit the signals
matter which atom of cesium used, thefrom the official atomic clocks to
frequency of resonance is always exactlyindividual receivers in atomic wall
the same. This is why atomic clocks areclocks and desk clocks all over the
so much more accurate than other clocksworld. In other countries, the signal
- the resonators in other clocks can bewould come from whichever clock is the
affected by lots of variables likeofficial atomic clock for that region,
temperature, moisture and atmosphericjust as the one in Boulder, Colorado is
conditions. None of these affect thethe one for the United States.
atoms, so the atomic clocks never loseThese amazingly accurate atomic clocks
or gain time.are also responsible for the fact that
Synchronization of Atomic Clocksall computers with built-in clocks are
The reason all atomic clocks show thesynchronized and accurate and keep time
same time anywhere you go is becausewhether on or off. With such accurate
they don't each have their own cesiumtime keeping and the use of GPS, you can
atom - this would be impossible becausebe sure that your atomic clocks will let
it's incredibly expensive and requiresyou know exactly what time it is, down
very precise conditions. Atomic clocksto the nano-second!
are actually receiving the time from a



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