Planck length

English

Etymology

Named after Max Planck, who defined it.

Noun

Planck length (plural Planck lengths)

1. (physics) A unit of length, believed to be the scale at which quantum gravity effects become significant, that is defined in terms of the speed of light, the gravitational constant and the reduced Planck's constant, namely: $\ell _{P}={\sqrt {\frac {\hbar G}{c^{3}}}}\approx 1.616252(81)\times 10^{-35}{\mbox{ m}}$

See also

• Planck scale
• Planck time
• Planck unit
• superstring