Planck time

The Planck time is a Planck unit and describes the minimum possible time interval for which the well known laws of physics is valid. It results from the time the light needs to travel a Planck length and to cause an (imaginary ) change in state. It was named after Max Planck.

For smaller time intervals, the time loses its familiar properties as a continuum. You would be quantized, that is, time would run below the Planck time in discrete jumps from. From the known physical laws it follows that any object that is shorter than going through a process in Planck time, becomes a singularity.

The Planck time is therefore also defined the first time after the Big Bang, which can be described physically.

Derivation

For the Planck time the estimate holds:

This formula combines the three fundamental physical constants

• Gravitational constant,
• Velocity of light,
• Reduced Planck constant.

The Planck time is therefore also a fundamental physical constant. The expression for is obtained directly from the demand for a product of powers of, and which has the dimension of time. The same applies to the Planck length and the Planck mass, which form the unit system together with the Planck time, which is used in relativistic quantum theories expediently.

Physical application

A practical significance of the Planck time has not been found. The smallest currently measurable time interval is about an attosecond (1 × 10-18 s ), which is therefore the 100,000,000,000,000,000,000,000,000 or 1 × 1026 times the Planck time.