Planck mass
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The Planck mass is the unit of mass, denoted by mP, in the system of natural units known as Planck units. Named after Max Planck, it is the mass for which the Schwarzschild radius is equal to the Compton length divided by π.
≈ 1.2209 × 1019 GeV/c2 = 2.176 × 10-8 kg
The 2002 CODATA-recommended value for the Planck mass is 2.176 45(16) × 10-8 kg, where the part in parentheses indicates the uncertainty in the last digits shown — that is, a value of 2.17645 × 10-8 kg ± 0.00016 × 10-8 kg.
Particle physicists and cosmologists often use the reduced Planck mass, which is
≈ 4.340 µg = 2.43 × 1018 GeV/c2.
Adding the 8π simplifies several equations in gravity.
Unlike most of the other Planck units, the Planck mass is on a scale more or less conceivable to humans, as the body mass of a flea is roughly 4000 to 5000 mP.
[edit] Significance
The Planck mass is the mass of a black hole whose Compton wavelength is comparable to its Schwarzschild radius. The Schwarzschild radius of a Planck mass black hole is the Planck length. Planck length, believed to be the scale at which General Relativity and the fundamentals of quantum physics become mutually important to describe mechanics at this specific scale.
[edit] See also
[edit] External links
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