A blink , a trice , or even saying " one Mississippi " . These are ways we attempt to count one second with our body . Whether it ’s the tick of a clock or a changing number on a digital display , the canonic whole of time describes the beat of our lives and underpin almost all scientific measurements . Butwhat is a second ?
The definition of a second
The definition that we apply today was agreed globally in 1967 . A indorsement is “ the duration of 9,192,631,770 periods of the radiotherapy gibe to the transition between the two hyperfine degree of the ground state of the cesium-133 particle . ” Basically , it is possible to aim an speck in a specific excited state and it will eventually flatten back to the ground state .
This transition can be used to make an fantabulous notch filter in the microwave range . Given its high-pitched stableness , this filter can be used to keep a beat . That is the bag of very precise atomic clocks . The definition was partially update in 2018 but was still free-base on the hyperfine modulation of the cesium-133 atom .
The 2d and its definition is cardinal to metrology , the science of evaluate matter . In fact , the metre , the kilogram , ampere , kelvin , and candela , which are respectively the unit of length , mass , electric current , temperature , and luminous volume , all depend on the definition of the second .
Redefining the second
While the definition has been great for many decades , investigator have been looking at the possibility of amend it even further . Technological breakthrough inoptical nuclear clocksare give birth precisions far beyond what a Hellenic cesium clock could get , such as getting thefastest clockand developing raw ways to makethese instruments .
“ As a worldwide principle , the definitions for the SI unit should be based on the measuring method that lead to the lowest dubiousness for all lower-ranking mensuration of amount based on those units,“Dr Liz Donley , head of the National Institute of Standards and Technology Time & Frequency Division , told IFLScience .
" optic frequence standards have extend to the level where they can perform frequency measure that are 100x more accurate than the mensuration that are performed using Cesium as the measure . ”
A potentialredefinition is in the cards , possibly in 2030 , but there are several strict requirements that must be accomplish before this can happen , including the ability to send the precise redefined secondly over fibre optic , for deterrent example .
It might not change the way we measure the moment of our life but it will be incredibly important in science . It will be like having a wrist watch that does n’t lose a second base even when left running for billions of years .
