B What can we see from the farthest reaches of the universe?

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The discussion centers on the concept of the universe's edge and what lies beyond it. Current models suggest that the universe is "flat" and potentially infinite, with no definitive edge. Some theories propose a closed universe where travelers could return to their starting point, while others consider a toroidal shape. The particle horizon defines the observable limit, but beyond that, the universe remains largely unknown. Ultimately, the question of what exists outside the universe is inherently unanswerable, as it falls outside the realm of scientific understanding.
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Hypothetically, what does the edge of the universe look like?

Past our known visible universe to the edge of the expanding universe what is it like?
 
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As far as we can tell there isn't one... at least, no reason to think there may be an edge way way out there the way you seem to be thinking.

The current simplest best model for the overall topology of the Universe is "flat, infinite".
It may be that the Universe is closed in the sense that hypothetical travellers could keep going in one direction and eventually and up where they started.
The simplest non-infinite Universe that fits the data would be Toroidal.
 
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You are effectively asking 'what is beyond all that is known'. A shaman would roll his eyes and simply respond 'the unknown'. A scientist would shrug and say 'nothing'. While that sounds pretty vacuous, it captures the essence of the question. You cannot picture the universe from outside the universe because everywhere and anywhere possible to go is, by definition, part of this universe. The only known constraint is called the particle horizon - the distance photons have traveled since the beginning of time and that 'boundary' continues to recede from us at light speed. Distance, however, is always relative to something and that something is the big bang: which turns out to be singularly unhelpful. The big bang occurred everywhere - not at some uniquely identifiable location.
 
@Lewis123 I recommend the link in my signature
 
Lewis123 said:
Hypothetically, what does the edge of the universe look like?
You are asking what exists outside of everything that exists.
 
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...
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