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