What is the Planck time?
The Planck time is t_P = 5.391247e-44 s (uncertainty ±6.0e-49). It is the time for light to travel one Planck length.
Open the interactive PhysRef tool →Key facts
| Value | 5.391247e-44 s |
|---|---|
| Symbol | t_P |
| Uncertainty | ±6.0e-49 s |
| Meaning | Shortest meaningful time interval |
| Source | CODATA 2018 |
Frequently asked questions
What is the value of the Planck time?
t_P = 5.391247e-44 s, the time light takes to cross one Planck length.
Why is the Planck time significant?
It marks the era after the Big Bang before which known physics cannot describe the universe.
How is the Planck time defined?
t_P = sqrt(ħ·G/c^5) = l_P/c, combining the fundamental constants.
Related pages
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