What is the Planck length?
The Planck length is l_P = 1.616255e-35 m (uncertainty ±1.8e-40). It is the smallest meaningful length scale in quantum gravity.
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| Value | 1.616255e-35 m |
|---|---|
| Symbol | l_P |
| Uncertainty | ±1.8e-40 m |
| Meaning | Quantum gravity length scale |
| Source | CODATA 2018 |
Frequently asked questions
What is the value of the Planck length?
l_P = 1.616255e-35 m, formed from G, ħ, and c, and considered the smallest meaningful length.
Why is the Planck length important?
Below it, classical notions of space break down and a theory of quantum gravity is expected to be needed.
How is the Planck length defined?
l_P = sqrt(ħ·G/c^3), combining the gravitational constant, reduced Planck constant, and speed of light.
Related pages
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