Comment on Astronomers spot the first “bounce” in our Universe
Shdwdrgn@mander.xyz 1 year ago
Reading through the description of this makes me wonder if the technique could ever be used to pinpoint the ‘origin’ of the big bang? If we knew where the boundaries of the universe were at we could roughly pinpoint the center, but that still assumes the universe is expanding at equal speeds in all directions. Still, knowing the origin point would probably help pinpoint our own location within the universe and provide better measurements for the age of the things we see in every direction.
Yearly1845@reddthat.com 1 year ago
[deleted]Shdwdrgn@mander.xyz 1 year ago
Well that was cool! Thanks for that, it actually cleared up some things for me.
recursive_recursion@programming.dev 1 year ago
I feel like this question is another possible route for how Nomai got sucked into the search for the Eye of the Universe
btw if anyone hasn’t played The Outer Wilds please don’t look up anything and play it for yourself whenever you can afford it. It’s a game you’ll probably wish you could wipe your mind in order to experience it for the first time again
btaf45@lemmy.world 1 year ago
if the technique could ever be used to pinpoint the ‘origin’ of the big bang?
There probably was no “origin point” because there was no singularity at the beginning of the big bang. The full universe may have been huge or even been infinite in size and even the observable universe had a significant size. There perhaps was a geographic center though, then and now.
Still, knowing the origin point would probably help pinpoint our own location within the universe and provide better measurements for the age of the things we see in every direction.
That would be the least of it. Knowing where a geographic center or boundary was would allow us to track absolute and not just relative motion. Then we could see what if any special properties apply to an absolute frame of reference.
Kata1yst@kbin.social 1 year ago
But the existence of a "geometric center" breaks several of the base assumptions of astrophysics. If there were a geometric center as you say, then there would have to be "edges" of the universe, or the inflation would need a center.
Both of which we think are not the case, due to lots of battle tested theories that tell us space is generally of flat curvature and homogenous, meaning one random chunk of space (the actual stuff of space, not like looking at stars and other structures of the universe) should be indistinguishable from another.
These days those assumptions are considered pretty fundamental to any understanding of space itself and the universe at large that we have.
btaf45@lemmy.world 1 year ago
These days those assumptions are considered pretty fundamental
Nope. The reason why the FLRW model does not include modelling boundaries is because it is very hard to model boundaries, not because they are unlikely.
en.wikipedia.org/wiki/Shape_of_the_universe
The reason a “flat” universe does not have boundaries is because none of the 3 curvature possibilities in the FLRW model have boundaries.
[For example, in the Friedmann–Lemaître–Robertson–Walker (FLRW) model, the universe is considered to be without boundaries…]
[Many finite mathematical spaces, e.g., a disc, have an edge or boundary. Spaces that have an edge are difficult to treat, both conceptually and mathematically. Namely, it is very difficult to state what would happen at the edge of such a universe. For this reason, spaces that have an edge are typically excluded from consideration.]
Conclusion: The primary reason why an apparent “flat” universe could still have boundaries is because the FLRW model is either incomplete or possibly even not the right model.
Kata1yst@kbin.social 1 year ago
There was no origin point. The universe was infinite with no edges when the big bang occurred, just like now. It just inflated in every direction to be a bigger infinity.
btaf45@lemmy.world 1 year ago
We don’t know that. Here is a depiction of infinite inflation, the most popular version of the standard model, spawning pocket universes with boundaries.
bigthink.com/…/https___specials-images.forbesimg.…
Kata1yst@kbin.social 1 year ago
Well no, we don't know that. But that's the current scientific consensus. Wouldn't make much sense to lay out every theory currently not disproven to answer a simple question though.
btaf45@lemmy.world 1 year ago
It’s not a consensus at all. The reason why the FLRW model does not include modelling boundaries is because it is very hard to model boundaries, not because they are unlikely.
en.wikipedia.org/wiki/Shape_of_the_universe
Assuming a finite universe, the universe can either have an edge or no edge. Many finite mathematical spaces, e.g., a disc, have an edge or boundary. Spaces that have an edge are difficult to treat, both conceptually and mathematically. Namely, it is very difficult to state what would happen at the edge of such a universe. For this reason, spaces that have an edge are typically excluded from consideration.
It’s not my “pocket universe theory”. It is the theory of Infinite Inflation, the most popular version of the standard model.
Those “pocket universes” are not really other universes. They are physically connected to our universe. They are called pocket universes because they are too far away to communicated with. The depiction I showed you is not an abstraction, it is what is believed to be the actual geometric shape.