Normally, when we think of clocks, we think of time — seconds, minutes, hours. When we think of scales, we think of weight — ounces, grams, pounds. However, a new clock developed by physicists at the University of California, Berkeley is said to be the most fundamental clock ever created, combining a clock’s function with a scale’s, telling time in matter.
Like lots of important inventions that furthered mankind — plastic, velcro, stainless steel, and the vitally important slinky — the invention of this clock was sort of an accident. Theatomic clock, which is the most accurate time-telling device of which we’re aware, measures time by tracking the fluctuating energy levels of the caesium-133 atom. One second is defined as how long it takes to complete 9,192,631,770 radiation cycles of caesium-133′s electrons transitioning between two energy levels.
Though the caesium method is currently the most accurate way to measure time, physicists know it’s not the only way to tell time using particles. Each particle has a frequency, known as the Compton frequency, which in theory can be measured. However, the Compton frequency is so staggeringly fast — 100 billion times faster than light waves — that we can’t measure it with today’s technology. Science wouldn’t be science if it didn’t try to solve that issue for the sole reason that it wasn’t currently solved, so Holger Müller and a team from Berkeley set out to remedy the issue.
The team set off on recreating Einstein’s twin paradox as a way to solve the issue of not being able to measure the Compton frequency. The twin paradox theorizes that if one twin stays on Earth while the other travels through space and then returns to Earth, the one who traveled through space will have aged more slowly than the one who stayed on Earth, because time passes by more slowly for moving objects.
Müller and his team tested the twin paradox by sending the caesium atom through an atom interferometer, which cut the atom’s wave in half, allowing one half to continue traveling while the other remained still — much like the twin that stays on Earth and the one that travels through space. Because the Compton frequency is so quick and difficult to measure, the team was instead able to measure the difference in frequency between the atom halves. However, the frequency depends on the mass of the halves, and because of that, this new method of attempting to measure time could determine weight.
Because this method of tracking the Compton frequency can determine the mass of a single atom, and the masses of relative atoms are known, you can chain some calculations together and figure out the mass of just about any atom. Unfortunately, a clock that can weigh you won’t be available on the market any time soon, because scaling atomic masses to larger objects is currently too expensive. However, the method has been tested, so maybe we’ll one day have a watch that tells us we need to lose some weight, just like mirrors tell us.