What Is A Second And How Will It Change In The Future?

Have you ever stopped to think about what a second really is? We use it to measure time in our daily lives, but do we truly understand its significance?

Back in 1967, a global agreement defined a second as “the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.” It may sound complex, but essentially it means that we can use the behavior of atoms to create incredibly precise atomic clocks.

These atomic clocks are the foundation of metrology, the science of measurement, and are crucial for defining other units of measurement like the meter, kilogram, ampere, kelvin, and candela. All of these units rely on the accuracy of the second.

While this definition has served us well for decades, researchers are now exploring ways to redefine the second using optical atomic clocks. These new clocks offer even greater precision than traditional cesium clocks and could revolutionize timekeeping.

Dr. Liz Donley from the National Institute of Standards and Technology explains that the goal is to base the definitions of SI units on the most accurate measurement methods available. Optical frequency standards now have the capability to measure frequencies 100 times more accurately than cesium standards.

A potential redefinition of the second is on the horizon, possibly by 2030. However, there are strict criteria that must be met before this can happen, such as the ability to transmit the redefined second over fiber optics.

This redefinition may not change how we experience time in our everyday lives, but it will have a significant impact on scientific research. Imagine having a clock that doesn’t lose a second in billions of years – that’s the level of precision we could achieve with a redefined second.