Bright Sword starts with the grenade flat.

Chapter 524 The Principle of Atomic Clock
Obviously, this can't be calculated like this! After all, this is affected by air pressure, and has nothing to do with the speed of time itself!

So when the speed increases, will the atomic clocks used for timing on spacecraft or satellites also have problems?
Just like a timer that uses dripping water to measure time is affected by air pressure.

So, will the faster speed also affect the counting of the atomic clock? This will make people mistakenly believe that this is caused by the slowing down of time.

You know, in order to accurately measure time, with the development of the times, time measurement tools are constantly updated, from sundials, hourglasses, water clocks, to mechanical clocks, quartz clocks, and then to atomic clocks, with higher and higher accuracy.

If the sundial, hourglass and water clock are Lu Ban ruler, then the mechanical clock and quartz clock are tape measures, and the atomic clock is the micrometer.

With the advancement and development of science and technology, in the 1930s, scientists discovered that the oscillation frequency of atoms was very accurate when studying the basic properties of atoms and atomic nuclei, which gave rise to the idea of ​​using the oscillation frequency of atoms to make clocks.

So in 1948, the National Bureau of Standards used the absorption lines of ammonia molecules to build the world's first atomic clock.

However, due to the Doppler effect, the oscillator spectrum is too broad and its accuracy is not higher than that of a quartz clock. Therefore, in 1949, the physicist Ramsey proposed a method to separate the oscillation field, which greatly improved the accuracy.

Later in 1955, the Yinhong Physics Laboratory successfully developed the first cesium beam atomic clock using cesium-133 atoms, the only stable isotope of cesium, thus ushering in a new era of practical atomic clocks.

By the end of the twentieth century, scientists had strictly regulated the conditions under which atomic clocks could be used and had greatly improved their accuracy by using techniques such as laser cooling and atom trapping and more precise laser spectroscopy.

Then, in the 21st century, scientists not only pursued the ultimate accuracy of atomic clocks, but also worked hard to make them miniaturized and energy-efficient.

This has enabled the new generation of atomic clocks to achieve a chip-level leap and greatly reduce energy consumption, thereby greatly optimizing stability and precision and entering the commercial promotion stage.

Atomic clocks are generally used in systems that require high time accuracy, such as satellite navigation systems, which mainly use time measurement to measure distance and ultimately achieve the purpose of navigation and positioning.

Time measurement mainly relies on atomic clocks placed on satellites and ground stations. Atomic clocks are like the "heart" of the satellite navigation system, and their accuracy directly affects the accuracy of satellite positioning, speed measurement and timing.

The rubidium atomic clocks commonly used on satellites can only be off by one second in hundreds of thousands of years. Even with such high time accuracy, satellite navigation systems can still have a positioning error of several meters.

Of course, because the satellite is flying around the blue planet too fast, it will cause the time dilation effect in the theory of relativity, slowing down the actual time of the atomic clock. So in order to avoid an increasing deviation from the ground time, the atomic clocks in the satellite positioning system are regularly calibrated with the atomic clocks on the ground.

Only in this way can the accuracy of satellite positioning be maintained and the error will not be too large.

However, why would the atomic clock, which is regarded as the most accurate, be affected by speed and become slower? This needs to be explained from the manufacturing and operating principles of the atomic clock.

You should know that an atom is composed of a central nucleus and electrons running in specific orbits outside the nucleus. Each electron has its own fixed flight orbit. When the outermost electron jumps from one orbit to another, the energy will change, and it needs to absorb or release electromagnetic waves. This electromagnetic wave has a certain frequency and is very stable. According to the current electronic watch principle, as long as we master the electromagnetic oscillation frequency corresponding to the hyperfine energy levels of a certain atom, we can use it to accurately time. Therefore, scientists use atoms as metronomes to maintain high time accuracy.

But how can we use this stable electromagnetic wave as a clock to measure time?

Early researchers developed different strategies for different atoms. For the rubidium atomic clocks carried on navigation satellites, the rubidium atoms were first "imprisoned" in a closed vacuum chamber and irradiated with light of 780 nanometers. The outermost electrons of the rubidium atoms absorbed the energy of the light field, jumped to another orbit, and self-radiated to the third orbit.

When all rubidium atoms have completed this step, they no longer absorb photons, and the fluorescence produced by the spontaneous emission of atoms cannot be observed. After that, a 6.8 GHz microwave is used to irradiate this group of atoms, allowing the electrons in the third orbit to return to the first orbit.

At this time, it can be observed that the rubidium atoms reabsorb 780 nanometer photons and spontaneously radiate fluorescence. By using the observed fluorescence intensity and feeding it back to correct the microwave signal, a highly stable microwave frequency can be obtained. This is the working principle of the rubidium atomic clock.

The cesium atomic clocks commonly used on the ground for time keeping use a completely different strategy. If the outer electrons of an atom are in different orbits, they will have different magnetic moments and will be subject to different magnetic forces in a non-uniform magnetic field.

The cesium atoms are first heated into gas and allowed to pass through a small hole to become a cesium atom beam, and then pass through a specific magnet. Atoms in different orbits will be deflected at different angles.

At this time, a beam of 9.2 GHz microwaves is used to irradiate these atoms, allowing the atoms deflected at a certain angle to achieve orbital jumps. Finally, a magnet in a specific direction is used to allow the atoms that have jumped to pass through another small hole. A sensor is used to detect the number of atoms in this part, which is converted into an electrical signal and fed back to control the frequency of the microwave source to obtain a microwave signal with a stable frequency.

With these microwave signals of stable frequencies, people can use electromagnetic means to convert them into standard frequencies for use in scientific research, communications, industry and other fields.

Electromagnetic means can also be used to convert this frequency signal into a series of pulse signals with an interval of one second, and then into the familiar time signal "hour, minute, second" for output. In this way, we have an atomic clock.

With the continuous maturity of laser and other technical means, in addition to the traditional rubidium clock, hydrogen clock, and cesium clock, new atomic clocks such as ion clock, cold atom fountain clock, and optical clock have emerged, and the accuracy index is constantly being refreshed. At present, the accuracy index of the best optical clock has entered the tenth to nineteenth order of magnitude.

Although the atomic clock sounds mysterious, it is actually not far away from people's lives and has been integrated into our lives.

Because in addition to positioning and navigation, atomic clocks are also used for time keeping and timing services throughout the world.

For example, the perych time we are familiar with is the result of the weighted average of more than 150 atomic clocks on the entire planet keeping time.

The measurement of various physical constants, as well as power systems and communication systems, all rely on high-precision atomic clocks.

Otherwise, deviations in grid regulation time may lead to motor failures, or even grid collapse in more serious cases. Differences in transportation system time in different places may cause traffic accidents and even casualties.

(End of this chapter)