There was a post here a couple of days ago that REALLY made me

That one's easy. Because gravity, space, and time didn't exist at the time of the Big Bang. In fact, the laws of phyics didn't appear until the BB was well underway (that is, after a few zillionths of a second, not several minutes.

>>8397240
"How long" did it take before the big bang happened.

Is that even something that can me measured in terms of "years"

How do you figure it out

>>8397245
You get a PhD in astrophysics.

>If the Big Bang actually occurred, how did matter and energy expand in the first several minutes of existence even if it had the combined gravitational pull of the entire energy content of the Universe stuffed in a single spot?

The universe today is observed to be flat, that means it is expanding just fast enough to overcome the force of gravity trying to collapse it. It's like escape velocity. A universe that is flat today means it was flat in the early universe so it was always expanding fast enough to overcome gravity.

It is not because gravity didn't exist.

>>8397240
>that is, after a few zillionths of a second, not several minutes

Sure, but in the minutes after those few zillionths of a second, when matter was literally in a single spot, how didn't a hypermassive Black Hole form, or how didn't gravity bend space and slow down time in that tiny pocket of a Universe?

>>8397222
I'm a brainlet. So I'll take a wild guess and say the acceleration of energy and matter outweighed the pull of gravity.

>>8397356
It's not the acceleration of the matter and energy that's the problem, it's the fact that the gravity created by them would've warped space to the point it was impossible for such an acceleration to exist in the first place, as time would be slowed down to infinity (and the fact that the energy that had mass was accelerated to such speeds would've made it even heavier, causing even more gravity around it)

The only explanation of that would be that gravity is not a constant and scales with time somehow, which means that it should get even stronger in the future and that less and less matter would be needed to cause a black hole, with it reaching a peak after a fuckton of years where every atom would technically cause a black hole. The problem with that is that its fucking retarded, so gravity can't be scaling with time progression.

So what exactly happened then?

>>8397222
Take a look at e.g. https://en.wikipedia.org/wiki/Lambda-CDM_model

Basically, you assume an isotropic, homogeneous universe, write down the Einstein equations (which simplify a lot), and solve (possibly with some approximations, which gives you an expanding universe.

>>8397358
This could be probably dismissed as a terrible thought but what ever. Dark Energy assuming it existed at the time out weighed all else, not to mention effects of big bang as it was.

Futhermore, what would the nature of matter be? Quarks or something? How do quarks interact with gravity?

>>8397222
In order for a black hole to collapse, there has to be a density variation within the universe. For the early universe, there were no such density variations (or very few of them).

Although, from another perspective, one could say it did. That we're living inside a singularity that is unraveling.

Isn't that how the higgs field works? Confering mass to matter, maybe at its start there was no matter, so it started expansion and instant after that matter began to gain mass, or maybe energy started to condensate into matter

>>8397222

Gravity is REALLY weak compared with the three other known forces, and it's theorised that another force exists but works at such high energies that it only acted for the first few fractions of a second, the "hyper-inflation" period.

I have no idea but just a thought, it seems likely to me that the same unknown force that overpowered the concentrated gravity in the first place is what continues to accelerate the galaxies currently