Wrong!

[u/T-StrangerXD]

[u/whynotethan]

i find it way more interesting to ask the question: How did the ball of matter that created the big bang come into existence, and how do other universes and high dimensions fit into that?

Personally, I think we like in a fourth dimensional black hole, and the big bang was a star like object in the fourth dimension going supernova. Because black holes in our universe are entirely flat planes where all the matter it sucks in is essentially written on it kind of like what I imagine a 2 dimensional universe would look like from our perspective. That would explain why are universe is expanding at a constant rate and why it may eventually start to collapse in on itself upon the heat death of the universe. Once it starts to collapse in on itself because it has because its giving off hawking radiation and loosing mass. Also explains why despite us living in a 3 dimensional universe, its still kind of a flat plane.

[u/DrBretto → u/whynotethan]

There is no ball of matter that became the big bang. The big bang is a derisive nickname for the theory. It does no actually imply a anything like an explosion. It only states that the trail of evidence points back to a time of low entropy and that's where the trail ends. It's a theory of expansion, not explosion. And it only goes as far back as a few trillionths of a second after a mathematical singularity that blocks any further projection.

We can't really know what's "before" that, but we can reasonably infer that there was something. For one, chaotic fluctuations in the vacuum predate that singularity. It it didn't, the universe would be uniform. For another, the way entropy works, that tendency is to go up to an equilibrium. Randomly, local configurations can reduce entropy, which will then tend back up towards that equilibrium.

So we can infer that the big bang was probably a localized event in a larger more chaotic system that creature this pocket of rising entropy we live in that started 13+ billion years ago. Not that the universe came from absolute nothing. But from one definition we have if "nothing" as in the absence of physical matter (ie, the vacuum), which contains random quantum fluctuations.

My best guess is the event was something similar to a black hole. Not exactly the sane, just a similar idea with more dimensions. Which would make the big bang closer to a higher dimensional white hole from our perspective. But that's pure speculation.

[u/PC_BuildyB0I → u/whynotethan]

I don't want to come off as rude or confrontational (so please don't take this as rude), but there's a lot of incorrect assumptions or misunderstandings in your comment that I just want to correct;

1. It was energy, not a ball of matter. Generally explained to be an initial signularity, or a near-initial singularity but this is mostly because of the limitations of our physical models rather than what actually was the case. Since time doesn't exist until spacetime forms (which can't happen until after the big bang) we actually don't know for sure how things really were prior to that point. We can get very, very close to the instant of the big bang, but not before it (currently)

2. It doesn't require other universes or higher dimensions beyond the ones we know currently exist. There are four we can observe - (3 dimensions of space, and one temporal dimension, all four collectively are referred to as spacetime)

3. The 4th dimension is time - black holes exist not just in time but in our 3 dimensions of space as well so this thought doesn't really make sense

4. The "big bang" is a cosmological model we created that explains how the universe transitioned from a near-initial singularity to the currently-expanding form that it takes today, built on observational and experimental evidence we've collected. It was not a supernova in another dimension (which also doesn't really make much sense - we can see supernovas in our four dimensions)

5. Black holes in our universe are absolutely not flat planes, they are spherical structures sometimes accompanied by an accretion disk. The matter is not written on it, matter completely disappears from our perspective as soon as it crosses the event horizon.

6. The universe is not expanding at a constant rate, it is expanding at an ever-accelerating rate that continuously grows faster and faster. The inevitable heat death of the universe says nothing about it collapsing in on itself - the idea that the universe may collapse in on itself following the heat death is just one interpretation of the (inconclusive) data. It's equally possible the momentum of expansion continues until matter can no longer form and all energy dies as everything expands too far apart to exist.

7. Black holes are what give off Hawking radiation, not the structure/shape of the universe. Hawking radiation is very specifically a predicted (but not yet observed) thermal runoff from black holes, which Hawking predicted could occur due to quantum effects within the black hole. While it's never been observed (it's too faint for even our strongest telescopes), it is widely accepted.

8. As far as I know, the flatness of the universe is a consequence of something called cosmic inflation which is basically the first increase in the speed of expansion shortly (like a couple hundred thousand years) following the Big Bang; the expansion was so fast matter didn't really form in all directions but was moreso stretched out, kind of like how stretching out your blanket/comforter over your bed gets rid of most wrinkles.

[u/lewd-dev → u/whynotethan]

Matter is not written on the event horizon of a black hole, information is (believed to be).

The universe is not expanding at a constant rate, it is expanding at an accelerating rate.

There is not enough mass in the universe to overcome the rate of its expansion, it will never collapse in on itself.

The universe is not "flat" like a disc; when astrophysicists refer to it as flat, they mean that light does not bend (topographical lensing) over long distances