Wait a second...

 

A year is made of 365 days. A day is made of 24 hours. An hour up of 60 minutes. And a minute is made up of 60 seconds. Essentially this concept of time perception that we have all been taught from elementary school all relies on the unit we have labeled a "second".  

What even constitutes a second?

I speak from personal experience when I say that I have never really given much thought to the concept of time measurement, especially its units such as "seconds". That's why Eran Tal's article,  "Making Time: A Study in the Epistemology of Measurement", really made me redefine and rethink how I view the concept of seconds. The article discusses the history of the second and how it came to be known how it is today. 

9,192,631,770 Hz, is the frequency of the radiation that is emitted as the Caesium-133 atom transitions to its lowest energy state also known as the ground state. Since 1967, 9,192,631,770 periods of this radiation emitted from the Caesium atom serves as the definition of the "second" (Tal 301). The basis of this definition relies on the assumption that the frequency associated with the Caesium atom is all the same. This assumption arises some issues, because this definition assumes that the Caesium atom is at the ideal conditions of 0 degrees K and no other fields or forces are influencing the transition to ground state (Tal 301). 

What's the issue? 

The issue that arises is that no clock can be guaranteed to function under such specific conditions of temperature. Therefore, this means that the standard clocks we use do not accurately measure time. There are certain clocks that can be run under these conditions, for example, the caesium fountain clocks that functions through caesium atoms being thrown up in a vacuum and falling down due to gravity and the radiation emitted can be measured (Tal 301). However, these clocks are very complex and there are issues in the ability to run them continuously, thus they serve as an unreliable time source. 

So...then what DO standard clocks measure? 

These Caesium fountain clocks display the value of the second that standard clocks theoretically should portray but can not due to the inability to meet the correct conditions. The standard second we all actually use is derived from international atomic time, that comes from a system of primary and secondary clocks whose results are averaged. In order to then get universal coordinated time known as UTC, leap seconds are used to help standardize seconds in accordance to geological differences (Tal 298). This leads to the argument made by Tal, that UTC and the time that we all universally use is merely a construction made by scientists. Therefore, standard clocks are all measurements made from assumptions and choices made by scientists based off clocks meant to represent standard time.