DeSitter cosmological horizon stability?

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Discussion Overview

The discussion revolves around the stability of the DeSitter cosmological horizon in the context of an expanding universe influenced by the cosmological constant. Participants explore the implications of potential evaporation of the cosmological horizon and its effects on cosmic expansion, touching on theoretical models and their speculative nature.

Discussion Character

  • Exploratory, Debate/contested, Speculative

Main Points Raised

  • One participant suggests that if the universe continues to expand at an accelerated rate, it may reach a DeSitter spacetime with a cosmological horizon that radiates similarly to black hole Hawking radiation.
  • Another participant questions the validity of this model, noting that it is speculative and currently untestable by experiment.
  • A participant raises the idea that even if the horizon tends to evaporate, the radiation could be reabsorbed by the cosmological horizon, potentially stabilizing it.
  • Concerns are expressed regarding the model referenced in the paper, with a participant indicating uncertainty about its validity and suggesting that it may imply a transition to flat spacetime.
  • There is acknowledgment that speculative models can contain inconsistencies that may not be immediately apparent.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the cosmological horizon's potential evaporation and its stability. The discussion remains unresolved, with no consensus on the validity of the models presented or their consequences.

Contextual Notes

Participants highlight the speculative nature of the models discussed and the lack of experimental verification, which may limit the conclusions that can be drawn from the current understanding.

Suekdccia
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TL;DR
DeSitter cosmological horizon stability?
If the universe keeps expanding at an accelerated rate (given by the cosmological constant) then the universe would approach a DeSitter spacetime where there would be a cosmological horizon that would radiate just as the event horizon of a black hole radiates Hawking radiation

I thought that once this state is reached, the universe would stay like that, but I recently discovered that this horizon could evaporate just like a black hole and the cosmological constant would dilute (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6560872).

Is this true? Even if that happened and the expansion would stop being accelerated by a cosmological constanr, what would happen then after?
 
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Suekdccia said:
Is this true?
It's a speculative model which we have no way of testing by experiment now or in the foreseeable future.
 
PeterDonis said:
It's a speculative model which we have no way of testing by experiment now or in the foreseeable future.
Even if this model was right and the horizon tends to evaporate, wouldn't the radiation eventually be reabsorbed by the cosmological horizon (balancing the process and keeping the horizon stable after all)?
 
Suekdccia said:
Even if this model was right and the horizon tends to evaporate, wouldn't the radiation eventually be reabsorbed by the cosmological horizon (balancing the process and keeping the horizon stable after all)?
The model in the paper does not appear to be saying that (it appears to be saying that the ultimate limit of the process is flat spacetime), but I'm not sure how valid the model in the paper is. As I said, it's speculative, and many speculative models turn out to have inconsistencies in them that aren't obvious at first glance.
 

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