How large was the universe at its moment of creation? Do we have a real answer for this? If so, how was this found out?
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We don't know. It might well have been infinite, and in fact the current thinking in cosmology (at least as expressed here on PF) is that that is the most likely scenario.BadgerBadger92 said:How large was the universe at its moment of creation? Do we have a real answer for this? If so, how was this found out?
Delta² said:According to Big Bang model (which is the most widely accepted model or not?):
The universe at the moment of creation was a single point (single point means zero dimensions) with infinite density.
weirdoguy said:Big Bang model does not say ANYTHING about moment of creation. And also it doesn't say that Universe was a single point with infinite density.
Delta² said:What does Big Bang says?
weirdoguy said:It says that over 13 bilion years ago (don't if its correct because in Poland bilion is a different number than in USA :P) Universe was in a hot dense state and it was rapidly expandind. Expansion means metric expansion. If Universe is infinite, then it was infinite back then. No explosion, no 'single point' with infinite density, no creation of the Universe. There are plenty of threads here about that, search it up.
Delta² said:where does the name Big Bang -comes from/relates to- if not about a big explosion?
Well, if you take the model literally then it does predict infinite density. For any finite density there exists some small time such that at all smaller times the density is greater than the target density. That is an infinite density, even if you exclude the singularity (which must be done for mathematical reasons).weirdoguy said:no 'single point' with infinite density,
Exactly. It's one of the most common, if not THE most common, pop-sci misrepresentations of actual science.Delta² said:Ok fine I guess I am victim of the most common or non common misunderstandings about Big Bang.
But it isn't at all meaningless. As has been discussed here on PF numerous times, "contracting objects" immediately runs into contradictions and is not a workable model.Feeble Wonk said:I think this issue is a common source of confusion to us non-physicists because of the general nature of the concept... “how large was the universe”. How “large” compared to what? We’re talking about the universe itself here. So “size” has no obvious meaning in terms to an “exterior” relationship. It can only be measured in terms of “interior” relationships. So, is the spatial dimension of the universe itself expanding, or is spatial dimension of the observable objects within the universe contracting? It seems as if it’s a meaningless question because the measurable parameters remain the same regardless.
Feeble Wonk said:Apologies. It was a loosely phrased comment. Actual “contracture” of dimensionless point particles is not at all what I was suggesting. What I was wondering was whether both sides of that question were essentially describing the same phenomenon. I’m afraid that this discussion will quickly diverge from the OP’s initial question, and that it will also quickly exceed my understanding of the subject matter. However, it’s always seemed to my ignorant conceptualization that the “expansion” of the universe’s spatial dimension is tied to a condensation of universal energy distribution. If that implies increased localization, would that not appear to be manifested in an apparent spatial expansion?
Feeble Wonk said:What I was wondering was whether both sides of that question were essentially describing the same phenomenon.
Feeble Wonk said:it’s always seemed to my ignorant conceptualization that the “expansion” of the universe’s spatial dimension is tied to a condensation of universal energy distribution
Scientists use a variety of methods and evidence, such as the cosmic microwave background radiation and observations of the expansion of the Universe, to estimate the size of the Universe at its moment of creation.
The size of the Universe at its moment of creation is still a topic of debate among scientists, but current estimates suggest that it was incredibly small, possibly even smaller than a single atom.
The Universe has been expanding since its moment of creation, which is supported by various observations and theories. The exact rate and history of this expansion is still being studied and debated by scientists.
Some theories suggest that the Universe may have a finite size at its moment of creation, while others propose that it may have been infinite. These ideas are still being explored and researched by scientists.
Due to the extreme conditions at the moment of creation, such as high temperatures and energy levels, it is difficult for scientists to accurately measure the size of the Universe at that time. Additionally, the lack of direct evidence and the limitations of our current technology make it a challenging task.