Planck mass

The Planck mass is a small unit of mass used in physics. It is derived using an equation involving Planck's constant, the speed of light in a vacuum, and the gravitational constant. It is approximately 21.76 µg.

The Planck mass can be thought of as an upper bound for the mass of a single particle. A particle with more mass would become a black hole.^[1] It's also a lower bound for the smallest possible black hole, since a black hole this small wouldn't be able to emit any Hawking Radiation to evaporate any smaller.

As with all Planck units, the idea was to have a definition based only on fundamental universal constants.

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↑ Faraoni, Valerio (November 2017). "Three new roads to the Planck scale". American Journal of Physics. 85 (11): 865–869. doi:10.1119/1.4994804. ISSN 0002-9505. Like all orders of magnitude estimates, this procedure is not rigorous since it extrapolates the concepts of black hole and of Compton wavelength to a new regime in which both concepts would probably lose their accepted meanings and would, strictly speaking, cease being valid. However, this is how one gains intuition into a new physical regime.

[1] Faraoni, Valerio (November 2017). "Three new roads to the Planck scale". American Journal of Physics. 85 (11): 865–869. doi:10.1119/1.4994804. ISSN 0002-9505. Like all orders of magnitude estimates, this procedure is not rigorous since it extrapolates the concepts of black hole and of Compton wavelength to a new regime in which both concepts would probably lose their accepted meanings and would, strictly speaking, cease being valid. However, this is how one gains intuition into a new physical regime.

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