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advanced_notions:hawking_radiation [2018/04/02 10:29] jakobadmin |
advanced_notions:hawking_radiation [2018/05/04 09:53] (current) jakobadmin ↷ Links adapted because of a move operation |
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<tabbox Concrete> | <tabbox Concrete> | ||
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+ | $$ T= \frac{\hbar c^3}{8 \pi G M k_B} ,$$ | ||
+ | |||
+ | where $k_B$ is the Boltzmann constant, $c$ the speed of light, $G$ the gravitational constant, $\hbar$ the reduced Planck constant and $M$ the mass of the black hole. | ||
+ | |||
+ | |||
+ | The temperature of a black hole is tiny. Putting in the numbers yields | ||
+ | |||
+ | $$ T= 6.169 \cdot 10^{-8} \text{ K } \ \frac{M_\odot | ||
+ | }{M}, $$ | ||
+ | where $M_\odot$ is the mass of the sun. In words this means that black hole with a mass equal to the mass of our sun would have a temperature of only $10^{-8}$ K. If the black hole is heavier, the temperature gets even tinier. | ||
+ | |||
+ | ---- | ||
* For a nice explicit discussion of the question "Where does Hawking radiation originate?", see [[https://arxiv.org/abs/1511.08221|Hawking radiation, the Stefan-Boltzmann law, and unitarization]] by Steven B. Giddings | * For a nice explicit discussion of the question "Where does Hawking radiation originate?", see [[https://arxiv.org/abs/1511.08221|Hawking radiation, the Stefan-Boltzmann law, and unitarization]] by Steven B. Giddings | ||
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</note> | </note> | ||
- | <tabbox Why is it interesting?> | + | <tabbox Why is it interesting?> |
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+ | This formula for the Hawking radiation shows why black holes are so important and interesting. In this little formula everything comes together: | ||
+ | * Quantum mechanics, in the form of $\hbar$ | ||
+ | * Gravity, in the form of $G$ | ||
+ | It tells us that black holes are laboratories for [[theories:speculative_theories:quantum_gravity|quantum gravity]]. | ||
</tabbox> | </tabbox> | ||