Did the classical universe have a beginning (renamed)

Did the universe have a beginning? Is the big Bang theory still the most dominant scientific theory for the beginning of the universe? What caused the primordial singularity to falter in density allowing the Big Bang to occur?

Maybe, maybe not. No one knows.

The Big Bang model explains what happened after the universe began not how it began.

You can ask cosmologists. They are the experts.

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  1. However there is more empirical evidence such as redshift and cosmic background microwave radiation which empirically shows that it most likely the big bang did occur so that would mean the universe had a beginning.

  2. Even if the laws of physics only go up into the point of the big Bang they still postulate that there was a primordial singularity prior to that.

You are conflating the “Big Bang” event with the “Big Bang model”. Let Sean Carroll (a renowned cosmologist and relevant expert) do the explanation:

So there you have it. The Big Bang model tells us nothing about the beginning of the universe.


No one really knows what happened at the Big Bang, per Carroll’s article. That singularity is hypothetical.


Nobody knows.

The big bang is not and never was a theory for the beginning of the universe, that’s a common misconception. The big bang is merely the name given to the theory that the universe expanded from an extremely hot and dense state approximately 13.7 billion years ago.

That the universe has a first moment of time in a singularity is an extrapolation.

We strictly don’t know that the universe expanded all the way from a singularity. That’s an extrapolation.

That doesn’t follow. The universe having expanded from a very hot and dense state(such as a singularity) does not imply it had a beginning. And even if it did have a beginning that merely implies there was a first moment of time.

It’s physics baby!


There is good evidence for the existence of the singularity. Yes it is an extrapolation, but the assumptions in the extrapolation is, as far as we know, quite robust. With some mild assumptions, we have a couple of relevant theorems:

  1. the existence of the “big bang singularity” is guaranteed in classical general relativity by the Penrose-Hawking singularity theorem

  2. the existence of a singularity, even if general relativity is false, is guaranteed classically by the Borde–Guth–Vilenkin theorem

I do not think it is fair to dismiss the existence of the Big Bang Singularity because it is an extrapolation.

However, what is often not appreciated is that singularity does not necessarily mean a point of beginning. In addition, singularity does not necessarily mean a point of infinite density. Singularity simply means that our equations (in this case, e.g., of general relativity) are no longer valid descriptions at the singular region, and thus cannot be used to compute/predict things at/past the singularity.


Thank you very much for that post. I agree with you as well the singularity only exists in mathematical theoretical form and not an actuality in the known universe, or that which can be empirically tested and verified using the scientific method. Therefore as far as we are concerned in the known testable empirical universe time started after the Big Bang.

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It may not imply that but it doesn’t preclude it either to quote you again the singularity is a mathematical theoretical model so we don’t know if that is the case in actuality the truth of the matter is everything that we can empirically test happens after the big Bang everything that we can prove happens after that so that is the beginning of time as far as we are concerned and the beginning of the universe

Proof is the wrong word. We observe some phenomenon. We observe, take measurements and postulate explanations. We build mathematical models and test them against our observations, then provisionally confirm, modify or discard the model.

To quote your words that was the 1st moment of time hence of beginning time started then so that would be the beginning of time materialist and atheists really don’t wanna admit that the universe had a beginning because it has too many philosophical and theological implications

Maybe, maybe not. We don’t know.


I never said proof I said evidence which may be indicative of but not necessarily conclusive

Right but there’s more empirical evidence to the fact that it did occur such of as redshift of stars as well as cosmic microwave background radiation also we are aware of the fact that time as we know it starts after the big bang

Please stop saying nonsense. That time began with the Big Bang tells us nothing about whether the universe had a beginning or not. There is nothing to admit or deny here.

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Hi everyone,

What do people think of this article by astrophysicist Ethan Siegel?

Surprise: the Big Bang isn’t the beginning of the universe anymore

Lastly, and perhaps most importantly, we can no longer speak with any sort of knowledge or confidence as to how — or even whether — the universe itself began. By the very nature of inflation, it wipes out any information that came before the final few moments: where it ended and gave rise to our hot Big Bang. Inflation could have gone on for an eternity, it could have been preceded by some other nonsingular phase, or it could have been preceded by a phase that did emerge from a singularity. Until the day comes where we discover how to extract more information from the universe than presently seems possible, we have no choice but to face our ignorance. The Big Bang still happened a very long time ago, but it wasn’t the beginning we once supposed it to be.


Thanks for posting a very interesting article.

Until the day comes where we discover how to extract more information from the universe than presently seems possible, we have no choice but to face our ignorance. The Big Bang still happened a very long time ago, but it wasn’t the beginning we once supposed it to be.

@PdotdQ what are your thoughts?

As I mentioned before, we do not know whether the Big Bang is the start time or not:

I am sorry that this is an unsatisfactory answer, but that is currently what we know.


As pointed out I think by others, the descriptions of general relativity may not hold beyond a certain point in the past when quantum effects predominate. The same is true regarding the BGV theorem. All it says is that the classical (general relativity) description of an expanding spacetime does not extend indefinitely into the past. That does not mean spacetime itself didn’t exist prior to that point, all it means that couldn’t be described according to classical physics.

Here is a video of someone I know who knows better than I do.

You’re next comment almost concede these points

That’s pretty much what we mean when we say that an actual singularity may not have been there. It’s a mathematical artifact of classical physics which may not accurately describe anything beyond certain conditions.

There’s absolutely nothing nonsensical about the fact that there’s more empirical evidence to the effect that the universe did have a beginning at the big Bang then there is contrary to it

So according to the gentleman in the video, “the classical expanding region of spacetime does have a beginning” and it’s precisely that region that is not only observable and empirically verifiable to us using sensory data input, but also happens to be the current universe we inhabit. So literally anything else beyond that is just theoretically possible through mathematic models and not neccessarily proven in actuality.