Atomic Time: How clocks really tick

Aditya Rengaswamy, Weird Science

I hate waking up for 8:30 a.m. classes to the insistent beeping of my alarm. But this morning, my alarm clock piqued my curiosity. I thought to myself, who exactly sets the times that we follow? Who makes up the scale and accuracy of these things? I did some research into this and found some interesting information.

Isidor Rabi, a physics professor at Columbia University, discovered the nature of protons that bind to atomic nuclei. His discoveries led him to develop a method for detecting molecular beam magnetic resonance. This resonance, or vibration, detection made time calculation more accurate. The National Bureau of Standards, which was responsible for keeping track of time in the 1930s, used this method with ammonium atoms, and the atomic clock was born.

Soon, research on the clock was moved to Colorado, where scientists continued to make improvements. Cesium was later used for time measurement in England; this became the standard because cesium gave a more accurate time reading than ammonium. Today, the world’s most common and affordable atomic clocks are only off by one second every 100 million years or so. Atomic clocks have far surpassed astronomical predictions of time in terms of accuracy.

Now, the International Bureau of Weights and Measurements (IBWM) uses atomic clock readings to keep the world’s countries on the same page. The IBWM is the authority on SI units everywhere, from kilograms to seconds. It is a collaboration of scientists and engineers from over 50 nations. Its Consultative Committee for Time and Frequency (CCTF) is responsible for international timekeeping, which is accomplished by atomic clock.

But the true masters of time are right here in America: the National Institute of Standards and Technology (NIST). The NIST, under the U.S. Department of Commerce, is an organization of some of the world’s best physicists, who have developed a timing device that blows cesium-based technologies out of the water. In 2010, the NIST developed single-atom quantum aluminum clocks that are cooled by lasers to near absolute zero. These atomic clocks boast unparalleled accuracy: they are off by one second every 6.8 billion years. Unfortunately, this kind of time measurement is too expensive to be practical.

Who would have thought that atoms are what give us the information we need to stay on schedule. It isn’t the sun anymore, or mechanized dials on a clock face – it is some of the tiniest known particles that show us where we are in the course of time. Jack Hardy, a writer for Saturday Night Live (which may I add is one of my favorite shows) once said, “I hope if dogs take over the world, and they choose a king, they don’t just go by size, because I bet there are some Chihuahuas with some good ideas.”

Join me next time as we continue to explore the bizarre aspects of our universe. From ecosystems to the solar system, there are always strange things happening around us.