DeSitter cosmological horizon stability?

In summary, the conversation discusses the possibility of the universe reaching a DeSitter spacetime where there would be a cosmological horizon that would radiate similar to a black hole. However, there is uncertainty about whether this horizon would eventually evaporate due to the cosmological constant diluting. The validity of this speculation is also questioned, as it cannot be tested by experiments currently or in the foreseeable future. There is also a discussion about whether the radiation from the horizon would eventually be reabsorbed, but the model in question does not seem to suggest this. Overall, the conversation presents a speculative model with uncertainties about its validity and implications for the stability of the cosmological horizon.
  • #1
Suekdccia
272
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TL;DR Summary
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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  • #2
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.
 
  • #3
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)?
 
  • #4
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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