I DeSitter cosmological horizon stability?

AI Thread Summary
The discussion revolves around the stability of the DeSitter cosmological horizon in an expanding universe influenced by the cosmological constant. It is suggested that, unlike a static state, the horizon could evaporate similarly to a black hole, leading to a dilution of the cosmological constant. Questions arise regarding the implications of this evaporation and whether the emitted radiation could be reabsorbed, potentially stabilizing the horizon. The validity of the speculative model being referenced is questioned, highlighting the challenges in testing such theories experimentally. Ultimately, the conversation emphasizes the uncertainties and inconsistencies inherent in speculative cosmological models.
Suekdccia
Messages
352
Reaction score
30
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?
 
Last edited by a moderator:
Space news on Phys.org
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.
 
https://en.wikipedia.org/wiki/Recombination_(cosmology) Was a matter density right after the decoupling low enough to consider the vacuum as the actual vacuum, and not the medium through which the light propagates with the speed lower than ##({\epsilon_0\mu_0})^{-1/2}##? I'm asking this in context of the calculation of the observable universe radius, where the time integral of the inverse of the scale factor is multiplied by the constant speed of light ##c##.
The formal paper is here. The Rutgers University news has published a story about an image being closely examined at their New Brunswick campus. Here is an excerpt: Computer modeling of the gravitational lens by Keeton and Eid showed that the four visible foreground galaxies causing the gravitational bending couldn’t explain the details of the five-image pattern. Only with the addition of a large, invisible mass, in this case, a dark matter halo, could the model match the observations...
Hi, I’m pretty new to cosmology and I’m trying to get my head around the Big Bang and the potential infinite extent of the universe as a whole. There’s lots of misleading info out there but this forum and a few others have helped me and I just wanted to check I have the right idea. The Big Bang was the creation of space and time. At this instant t=0 space was infinite in size but the scale factor was zero. I’m picturing it (hopefully correctly) like an excel spreadsheet with infinite...
Back
Top