What is the temperature of the black hole?

Question

Are black holes hot or cold? I was thinking because I wanted to know if there any human sustainable temperature so we can travel in it.

Forget about traveling there. There's no solid surface to stand on, not to mention that doing so would turn you into a puddle of neutrons anyways. — John Dvorak, Dec 04 '19 at 19:27
Related question: https://astronomy.stackexchange.com/q/26427/24157 — , Dec 04 '19 at 20:27

score 3 · Answer 1 · edited Dec 05 '19 at 05:38

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See Hawking radiation. The temperature of a black hole depends on its mass, and is given by:

$T=\frac{hc^3}{16\pi^2GMk_B}$

Where $h$ is the Planck constant, $c$ is the speed of light, $G$ is Newton's gravitational constant, $M$ is the mass of the black hole, and $k_B$ is the Boltzmann constant.

edited Dec 05 '19 at 05:38

PM 2Ring

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answered Dec 04 '19 at 20:25

Allure

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There's a nice Hawking radiation calculator – PM 2Ring Dec 05 '19 at 05:40

score 2 · Answer 2 · edited Dec 05 '19 at 04:08

If you are talking about the temperature of the event horizon, then it depends on the mass. Super-massive black holes have a temperature of $1.4 \times 10^{-14}$ Kelvin while a solar mass black hole has a temperature of only $6.0 \times 10^{-8}$ Kelvin. This temperature comes from the proposed Hawking radiation of black holes$^1$. The reference below gives some temperatures for very small black holes.

https://phys.org/news/2016-09-cold-black-holes.html

What is the temperature of the black hole?

2 Answers2