The big bang refers to the rapid expansion, not an event prior.

The universe wasn’t just hot and by human standards, it was smaller than an atom and consequently ridiculously hot

> - Current observations and known physics suggest that the known universe, at some point in the past, existed in a very hot state, at a very dense/small scale (by human standards). What happened (or existed) before this point is completely unknown.

Yep

> - There is no evidence or indication to determine a big 'bang' - in the more literal sense - actually occurred prior to this point. Thats just our extrapolated/romanticised way of explaining how we arrived from the earliest-understood-limits of the above (small+dense universe)... to present day observations of a big-cool-increasingly-expanding universe (either realtime or via obvservational glimpses effectively back into long ago via JamesWebb/Hubble etc). > > - There is no evidence to suggest there was 'nothing' at a point prior to this expansion. Thats just a extrapolated/romanticised way of answering the tantalizing question 'what came before?' in a neat way the human mind can quantify. > > - There is no evidence to suggest anything/everything was actually 'created' in the Big bang. Thats just our extrapolated/romanticised way of imagining how the universe came to be. Our knowledge of current physics and models simply state that the universe was once in a dense, small space... nothing about whether it said material was actually 'created' in some kind of event prior to this snapshot state.

Many widely accepted models indicate that spacetime as a whole (ie time + 3D space + all the energy) started at the big bang, so "before" or "prior" have essentially no meaning in this context.

And yeah, our current models of physics have no meaningful suggestions for how the universe began in such a state, just that it did.

Fundamentally, it's the only white hole we've been able to observe - but how or why 4D spacetime plus energy is streaming from this zero surface is essentially unknowable until and unless we find ways to experimentally probe higher dimensional stuff outside our universe (eg Branes).

not a scientist, but this is my understanding of things too.

the "big bang" was originally coined as a pejorative way to describe the idea. it just stuck because it's catchy.

our physics goes so far back, to a certain point. and it looks like the math would go back to a zero size point. which is how we get to fractions of a second after the big bang. but that's just using similar math to: a plant is growing 1cm a day, it's 10cm now, so 10 days ago it must have been 0 size.

our physics doesn't describe the early universe beyond a certain point, so we can't actually tell what it was like. and we know there's 4 big problems in current physics, all of which would affect this:

• quantum mechanics and Einstein don't align
• quantum mechanics does not describe what collapses the wave function
• we don't know what dark matter is
• we don't know what dark energy is

and these are just the "known unknowns".

however, "the big bang" remains the most plausible model, describing the cosmic microwave background and the current expansion and distribution of matter within the universe.

some of the big things we know we don't know about it:

• what happened at t=0 and just after, if t=0 really was the start of everything or just some inflection point
• why we appear to have mainly matter and not matter + antimatter

I'm sure there's a bunch more things we don't know. but your characterisation seems accurate to me.

If everything in the literally sense was effectively in one point wouldn't it not just be ridiculously hot, but infinitely hot? Or would it be maximum possible hot?

By this stage in the model we are pretty much into the realms of pure mathematics, and unfortunately mathematics is a part of physical reality which means logically it cannot model or totally explain physical reality. Which is partially why we refer to such things as singularities. The points at which we cannot go further because our models break down and meaningful information can no longer be extrapolated.

So my critique of your bullet points would be that they are seeking to criticise a system and model as being inadequate, when the model and modellers are well aware of that inadequacy and that is the very thing that people like Hawking and his team were wrestling with for many years.

That isn't to undermine your central point, that the endeavour of popular science is to use analogies with simpler concepts to express complex ideas to the wider population.

But, you seem to be somehow attacking that endeavour or at least trying to suggest it is somehow "romanticised" or to use the word I think you want to say, "lying".

Only a very small percentage of the population are remotely interested in going deeper into the maths and physics of these first moments of the universe and what they imply. But, those fields are equally well represented in popular science, all be it slightly less 'best selling'.

Saying everything was a point, it means infinitely dense. Infinitely dense means infinitely hot. But whenever you see infinites, the correct conclusion is: we don’t know.

T0 is unknowable

My ex-wife knows everything, ill ask her.

Yup! Current mathematics says very hot state at very small, dense volume in the very distant past. I wouldn't include "observations" in this statement as what you're discussing is based on using known observations and going backwards. It's more of a "indirect observation."

A few things you're misinterpreting are about the Point itself which I'll capitalize for clarity and define as "the atom-sized moment in time and span where the universe was very hot & very small." Mathematically, there is no before. There can't be "negative time". Yes there is the past, but the Point is t = 0. There is no time before 0 in reality (though there is in math obviously)

The Big Bang doesn't happen before the Point. It is the explosion that occurs when the Point cannot contain itself any longer. Again, there is no negative time in reality.

Yes! The data is extrapolated from known observations i.e. we know the stars in the sky are getting farther away from us, so if we do the math and go backwards, then the universe must have started at a single point. And again, if it is a single point, that all the matter in the universe makes it very hot and very dense.

Yup! When anyone says there was "nothing before" they're typically using the math in their favor. Remember that math is just math. Numbers being numbers. Some human as to interpret them. So, if universe is expanding, then in distant past it was a single point. If universe was a single point, then even before then, it was nothing. These folks are using the "negative time" that makes sense on paper (in math), but doesn't make sense in reality. Again, remember "negative time" is not the same as "the past." You can go back in time in math or theoretical reality but you can't have time before time even existed.

There is every piece of evidence that anything/everything was 'created.' You're misinterpreting the when of the Big Bang. Big Bang happens sometime after t = 0. That explosion is used to explain when the weak/strong intermolecular forces began to actually work. There was space now for sub-subatomic particles to exist. So nuclei formed. Then gravity began to exist. Then literally everything else happened.

I agree that the Big Bang is romanticized but if you're reading up about the Big Bang in outlets that write about it that way, you're not looking in the right spot anyway.

It's romanticized in high school or young children's programs because this topic is several decades of lectures/papers/experiments. How do you expect to get people to do science or math, if they think it's inherently boring?

Again, it's rooting in math. It's not guesswork, we're working backwards. You even mention this yourself.

It's not that we know less than we think. It's that everytime we answer a question, we come with 100s of other questions. We have to make sure we're right. We don't just stop?

Calling the Point the "Hot Dense Universe State Snapshot" would be correct. The Big Bang is the part that happens after.

Thats a good point. But I wonder how many people, in a random sample of X size, would know the Big Bang more accurately should be interpreted to refer to 'an expansionary event' instead of 'a creation-ary event'.

The expansion was very rapid. Almost like…. an explosion - a bang, if you will

It's surprisingly compatible with the Christian view of creation.

But then Lemaître was also a Catholic priest, so perhaps not so surprising really that his scientific theorising might have an element of theological basis.

While the science is mostly heading in the direction of his theory, it's kind of like the concept is so enormous, with so much information impossible to capture at present, that almost any brilliant theory could be presented and evidence to support it could be found...

...but of course that would depend on more brilliant theories being developed and indeed taken seriously.

And it may be that this brilliant theory with heavy reference to theological concepts takes us all the way to an answer or even a new discovery.

Big Bang is a fictional idea used by scientist becuase they can’t explain how the universe became

god

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If a Bang happens and there is no one to hear? The rest have covered the size and some of the time issues fairly well.

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>that almost any brilliant theory could be presented and evidence to support it could be found... And it may be that this brilliant theory with heavy reference to theological concepts takes us all the way to an answer or even a new discovery.

Can have some fun with stuff like this.

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Theory: The universe as we know it (via the big bang) came about via the final death throes of a dying God, who effectively committed suicide. (lets call the physical sub-atomic singularity this entity occupied something catchy, like.... The God Particle).

Said particle existed as everything and anything in a state of perfection, but eventually grew tired of an Omnipotent state of being.. and yearned for freedom from the burden of embodying unyielding perfection.... wishing its own destruction upon itself..... setting forth an event/act humans would one day come to know as creation / The Big Bang.

In the ^ fan fiction, none of that is actually provable to be untrue, correct? We can say the Big Bang (or great expansion) came about as a sudden expansion of the universe from a hot+dense state from the earliest moments, but that doesnt preclude the possibility that said state at T=0 was the physical embodiment of God itself. (I just like the idea of juxtapost idea of It destroying itself in an act that would later be regarded as creationary) ;)

Which, as you said, brings observations that creationary theory from a science POV can be surprisingly compatible with theological fanfic concepts.

It’s a theory that describes how the universe began and scientists agreed that the universe was created with an event known as the Big Bang.

Terminological theories are built from standing on the shoulders of giants as Isaac would say and it is amazing, we have an understanding of so much and that evidence is all around us, with that knowledge and understanding forever expanding like the universe.

Google to learn more on the subject and don’t waste your time on goat herders’ books.

Check out a YouTube by FermiLab (I think). The video walks back time from now until some known point, if I remember, 10 to the 14th fraction of a second after the Big Bang. The thing I found interesting is that for the first few hundred thousand years the universe was a large mass of plasma expanding and cooling. No atomic particles existed. The background radiation left over is what we can still detect and measure / map time. Great vid. Probably 20 minutes. Well worth the time.

>It’s a theory that describes how the universe began

No, unless im misunderstanding something here? How are you defining 'began'? Because if 'began' is T=0, then no, the big bang doesnt describe that. Right? It describes the initial rapid expansion happening while the universe was in a certain state.... its quite a jump to assume said state should be labelled as 'began' - as if nothing came prior.

Thanks. Am having a watch of https://www.youtube.com/watch?v=dr6nNvw55C4 now at your suggestion :)

semantics, google how the universe BEGAN, and learn

Probably not many but it doesnt matter at all.

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You seem like someone with a lot of vague youtube knowledge convinced they know more than the entire scientific community

Go ahead, say extrapolated/romanticised one more time..

I like Don Lincoln videos.

I get several things from this video.

• Astronomers can see the CMB, visible 380,000 years after the Big Bang.

• Explanations of the early universe from 380,000 years ago to 10-13 seconds after the Big Bang are based on observations in particle accelerators creating the hot, energetic conditions of the early universe. My point is that these explanations of the time before what astronomers can observe with telescopes are NOT only mathematics as some appear to claim.

• Explanations from 10-13 to 10-43 seconds after the Big Bang are mathematics based on known laws of physics.

• Known laws of physics break down at 10-43 seconds after the Big Bang. Descriptions of the universe before 10-43 are only speculation which at best don't contradict known observations, physics and mathematics.

The theory basically says "the universe started out as a singularity, a point of infinite density where all of our knowledge of physics breaks down. Then all that energy, matter, and spacetime expanded outward."

It's the point at which reality twists beyond all recogniton. Reality includes time. Our personal clock started then for any practical purposes because to the best of our ability to study it, the point of arbitrary density included time being busted.

Whether existence is a cycle , whether our universe is floating ina higher dimensional space, etc, there could have been other places with their own time flowing. Those ideas are a million years beyond our ability to research so they're the realm of abstract math or daydreaming. Hypertime and previous universes just can't be a part of anything we do in the observable universe yet. We're compartmentalizing because omniscience is impossible.

If you feel like scientists are playing word games and are using a gross and weird definition of time, you're gonna have to learn to deal with it. People who do the research know the limitations of the models and just use the language that lets them talk to their peers without going nuts referring to "time before the universe" like flavor text in a video game.

If you feel like the public just doesn't understand this well enough: probably! Science writing for the public is an absolute nightmare of a job

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If you are young I suggest you eat well and stay in good health and live up to around 2050 , by then we can collectively hope somebody would have solved the mismatch between quantum and classical physics , only then we would have the answer. answer lies in the weird ass quantum world .. entanglement ,time dilation , length contraction and quantum tunnelling ,superposition etc... I'm not buying "hot ,dense and smaller than an atom" universe

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