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.

  • $\begingroup$ 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. $\endgroup$ Dec 4, 2019 at 19:27
  • $\begingroup$ What kind of energy is present in there? $\endgroup$
    – Shaun
    Dec 4, 2019 at 19:29
  • 1
    $\begingroup$ Related question: astronomy.stackexchange.com/q/26427/24157 $\endgroup$
    – user24157
    Dec 4, 2019 at 20:27

2 Answers 2


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


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.


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.

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

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