Planck scale

This article deals with the Planck scale; for the system of units see: Planck units .

The Planck scale , named after Max Planck , marks a limit for the applicability of the known laws of physics .

Orders of magnitude

Planck length

Distances of the order of magnitude of the Planck length are far beyond direct experimental accessibility and would have to be described with the help of a quantum theory of gravity , which so far only exists in rudiments. In string theory , the characteristic length scale of the strings is in the order of magnitude of the Planck length. ${\displaystyle l_{\mathrm {P} }}$

${\displaystyle l_{\mathrm {P} }}$is about times smaller than the diameter of the proton. ${\displaystyle 10^{20}}$

Planck energy

If one wanted to investigate such small structures with a particle accelerator , the wavelength of the particles used would have to be comparable to , or their energy would have to be comparable to the Planck energy . The only conceivable process in which comparable energies could have occurred is the universe about one Planck time unit after the Big Bang . ${\displaystyle l_{\mathrm {P} }}$ ${\displaystyle E_{\mathrm {P} }}$

Planck mass

The Planck energy via associated mass is almost on the "human" size scale - a flea weighs 4000 to 5000 Planck masses. ${\displaystyle E_{\mathrm {P} }}$ ${\displaystyle E=mc^{2}}$

With particle energies corresponding to the Planck mass, the De Broglie wavelength is comparable to the Schwarzschild radius . ${\displaystyle \lambda ={\frac {h}{p}}}$

${\displaystyle m_{\mathrm {P} }}$is about GeV . ${\displaystyle 10^{18}}$

Planck time

In the Planck time, the light runs through the Planck length. In order to resolve times on the Planck time scale, energies in the order of magnitude of the Planck energy are necessary (see energy-time uncertainty relation ) - with the consequences mentioned above.

literature

• Giovanni Amelino-Camelia , Jurek Kowalski-Glikman (eds.): Planck scale effects in astrophysics and cosmology , Lecture notes in Physics 669, Springer, Berlin 2005, ISBN 3-540-25263-0
• Richard L. Amoroso, Geoffrey Hunter, Menas Kafatos and Jean-Pierre Vigier (Eds.): Gravitation and cosmology - from the Hubble radius to the Planck scale. , Vigier 80th Birthday Symposium, Kluwer Academic, Dordrecht 2002, ISBN 1-4020-0885-6
• Nick Huggett, Craig Callender: Physics meets philosophy at the Planck scale - contemporary theories in quantum gravity. Cambridge Univ. Press, Cambridge 2001, ISBN 0-521-66445-4

See also

• Planck units

Web links

• What is the Planck world? from the alpha-Centauri television series(approx. 15 minutes). First broadcast on July 21, 2004.