Planck time

The Planck time is the natural unit of time, denoted by tP. It is considered the smallest possible measurement of time.

Related Topics:
Natural unit - Time

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t_P = sqrt{rac{hbar G}{c^5}} pprox 5.391 × 10−44 seconds

Related Topics:
5.391 × 10⁻⁴⁴ - Second

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where:

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:hbar is the reduced Planck constant (or Dirac's constant)

Related Topics:
Reduced Planck constant - Dirac's constant

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:G is the gravitational constant

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:c is the speed of light in a vacuum

Related Topics:
Speed of light - Vacuum

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The Planck time is the time it would take a photon travelling at the speed of light to cross a distance equal to the Planck length. This is the "quantum of time", the smallest measurement of time that has any meaning, (roughly 10−43 seconds). Within the framework of the laws of physics as we understand them today, we can neither measure nor discern any difference between the universe at the time it first came into existence and the universe anything less than 1 Planck time later.

Related Topics:
Planck - Photon - Light - Planck length - Quantum - Second

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The estimated age of the Universe (4.3 × 1017 s) is roughly 8 × 1060 Planck times.

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