# Does the cosmological horizon have entropy and temperature?

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Black hole horizons have temperature and entropy. Does this also apply to the cosmological horizon?

Does the cosmological horizon have a temperature, for example? And what is its value?

Is the entropy of the cosmological horizon the same as that of a black hole?

edited Sep 27, 2019

Why not? even the vacuum has temperature.

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A partial answer only: researching the issue, I found this paper: https://arxiv.org/abs/hep-th/0407255

The paper argues that the temperature of a de Sitter horizon is negative, whereas the entropy and energy remain positive. But the values are not yet clear to me.

answered Sep 28, 2019 by Chri

On the other hand, all papers on de Sitter space imply that the temperature of the horizon is

$$T = \frac{\hbar c}{ 2 \pi k} \, \frac{1}{R}$$

which gives $10^{-30}$ K, much less than the 2.7 K of the cosmic background radiation.

Is it reasonable to speak of the horizon "temperature" and forget about the matter in between?

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