| If time is crucial to you or your | | | | shared location where one of the world's |
| office, consider investing in atomic | | | | few of the world's atomic clocks |
| clocks so that everyone knows exactly | | | | operates. A low -frequency radio signal |
| what time it is and everyone has the | | | | broadcasts the time from that location |
| same time. These are the most accurate | | | | to all atomic clocks within its range. |
| time keeping pieces you can get, and | | | | There are currently approximately 200 |
| more and more businesses are using | | | | atomic clocks world-wide in sixty |
| atomic wall clocks to make sure that | | | | countries. |
| accurate time sheets and appointments | | | | In the United States, most atomic clocks |
| are kept. | | | | used for home and offices are |
| But what are atomic clocks and why are | | | | synchronized to the National Institutes |
| they so much more accurate than regular | | | | of Standards and Technology atomic clock |
| clocks? A standard clock, whether | | | | in 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 is | | | | the official time clock of the |
| the device that actually keeps track of | | | | Department of Defense. Since both of |
| time. In most clocks the resonator is | | | | these atomic clocks are within one |
| either a swinging pendulum or (in | | | | second of each other over a million |
| digital clocks) oscillations in the | | | | years of time, it is unlikely that time |
| power line (which is a bit different in | | | | displayed on atomic wall clocks at the |
| the U.S. and in Europe). | | | | Pentagon will differ from the time |
| Atomic clocks also use a resonator, but | | | | displayed on an atomic clock in your |
| the resonator counts based on the | | | | home office! |
| resonance frequency of atoms. Resonance | | | | How Do At-Home Clocks Get the |
| is the emission or absorption of | | | | Information from Master Atomic Clocks? |
| microwave electromagnetic radiation by | | | | Global positioning satellites (GPS) in |
| an atom. It is very regular, and no | | | | the skies above us transmit the signals |
| matter which atom of cesium used, the | | | | from the official atomic clocks to |
| frequency of resonance is always exactly | | | | individual receivers in atomic wall |
| the same. This is why atomic clocks are | | | | clocks and desk clocks all over the |
| so much more accurate than other clocks | | | | world. In other countries, the signal |
| - the resonators in other clocks can be | | | | would come from whichever clock is the |
| affected by lots of variables like | | | | official atomic clock for that region, |
| temperature, moisture and atmospheric | | | | just as the one in Boulder, Colorado is |
| conditions. None of these affect the | | | | the one for the United States. |
| atoms, so the atomic clocks never lose | | | | These amazingly accurate atomic clocks |
| or gain time. | | | | are also responsible for the fact that |
| Synchronization of Atomic Clocks | | | | all computers with built-in clocks are |
| The reason all atomic clocks show the | | | | synchronized and accurate and keep time |
| same time anywhere you go is because | | | | whether on or off. With such accurate |
| they don't each have their own cesium | | | | time keeping and the use of GPS, you can |
| atom - this would be impossible because | | | | be sure that your atomic clocks will let |
| it's incredibly expensive and requires | | | | you know exactly what time it is, down |
| very precise conditions. Atomic clocks | | | | to the nano-second! |
| are actually receiving the time from a | | | | |