Quantcast
  • Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.

News

PO is now at the Physics Department of Bielefeld University!

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback

Attributions

(propose a free ad)

Site Statistics

205 submissions , 163 unreviewed
5,047 questions , 2,200 unanswered
5,345 answers , 22,709 comments
1,470 users with positive rep
816 active unimported users
More ...

  Does the cosmological horizon have entropy and temperature?

+ 0 like - 0 dislike
1209 views

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?

asked Sep 26, 2019 in Astronomy by Maria [ revision history ]
edited Sep 27, 2019

Why not? even the vacuum has temperature.

1 Answer

+ 1 like - 0 dislike

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 [ no revision ]

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?

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.
Live preview (may slow down editor)   Preview
Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
p$\hbar$y$\varnothing$icsOverflow
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
Please complete the anti-spam verification




user contributions licensed under cc by-sa 3.0 with attribution required

Your rights
...