The Engineer Guy explains how an atomic clock works

The atomic clock is a device that the world depends on much more than the average person is aware of. Able to keep time more accurately than the motion of the Earth or the position of the stars, several systems that you would find to be indispensable rely on atomic clocks that are powered by cesium atoms .

The Global Positioning System and the Internet are two such examples that make use of the fact that atomic clocks lose a second once every 138 million years. Bill Hammack, better known as the Engineer Guy, narrates an excellent instructional video about this topic, which you can watch above.

The world’s first atomic clock was completed in 1955 by scientist Ray Essen. Since then researchers have worked to create three different types of the ultra accurate time keeping devices: hydrogen, rubidium and cesium powered clocks all are much more accurate than Essen’s version pictured above. Cesium is the most widely used element in these clocks because of the ease with which it can be manipulated using heat, normal magnets, and quartz.

As far as how the world’s GPS system relies on atomic time keeping, it all breaks down to the fact that the GPS receiver in your phone or vehicle is communicating with 4 of the 24 different location satellites that are in orbit around the Earth at the speed of light. Because of the distance from these orbiting devices to the ground, if their timekeeping is off even by one millisecond that kind of error can translate into a misreading of several hundred miles. With atomic time keeping, each satellite can compensate for both its movement in the sky and the movement of your vehicle as well.