X-Nico

3 unusual facts about Schwarzschild radius

D-brane

The Bekenstein entropy is proportional to the black hole mass squared; because the Schwarzschild radius is proportional to the mass, the Bekenstein entropy is proportional to the black hole's surface area. In fact,

Gravitoelectromagnetism

However, the pulsar is spinning at a quarter of the speed of light at the equator, and its radius is only three times more than its Schwarzschild radius.

Shapiro delay

which is the extra distance the light has to travel, where $R s$ is the Schwarzschild radius.

Planck particle

A Planck particle, named after physicist Max Planck, is a hypothetical particle defined as a tiny black hole whose Compton wavelength is equal to its Schwarzschild radius.

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While opinions vary as to its proper definition, the most common definition of a Planck particle is a particle whose Compton wavelength is equal to its Schwarzschild radius.

Micro black hole

For sufficiently small M, the reduced Compton wavelength ( $\scriptstyle{\lambda \; = \; \hbar/Mc}$ , where ħ is Reduced planck constant) exceeds half the Schwarzschild radius, and no black hole description exists.