What is the smallest measurement of time? © Getty Images

What is the smallest measurement of time?

Time is an abstract concept at the best of times but these dimensions are so tiny that the classical laws of physics no longer count.

Asked by: Steve Collins, by email

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The smallest viable measurement of time is derived from a unit of distance called the Planck length. It’s where dimensions become so tiny that the classical laws of physics break down and quantum effects kick in. It works out at about 1.6 x 10-35m. From here, physicists speak of the smallest theoretical period of time as being the interval required for a photon travelling at the speed of light to cover the Planck length, or just 0.5 x 10-43 seconds. Don’t worry if values like 10-43 seem a bit abstract and meaningless, they’re right at the extreme end of physics.


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