B Big Bang Question -- How was the first matter formed?

[sysprog]

I agree, but again you are changing the subject. You keep dancing around the fact that you stated that if the universe were finite it had to be bounded. Do you still believe that?

I didn't state that; I asked wasn't it so $-$ I introduced the notion by raising a question; not by making a statement $-$ your point that finiteness does not entail boundedness is well taken.

 

[phinds]

I didn't state that; I asked wasn't it so

Well, nuts. You are right of course. I sometimes get obsessed by something and I got it in my head that you had stated that. Sorry.

 

[sysprog]

Well, nuts. You are right of course. I sometimes get obsessed by something and I got it in my head that you had stated that. Sorry.

No sweat, Sir, and thanks for being such a great contributor to human understanding $-$ really

 

[Ibix]

The usual FLRW models are infinite or finite but unbounded, depending on the initial conditions you feed in. The latter has spherical symmetry, so a line (drawn along a surface of constant cosmological time if you want to be pedantic) forms a closed loop of the same length whatever direction you pick. As I said earlier, the current best data is consistent with zero or negative curvature (infinite) and positive curvature (finite and unbounded, but very, very large).

We recently had a discussion about whether it's possible to have a finite bounded universe, at least in the sense that you could describe such a thing mathematically. I'm not sure we came to a firm conclusion either way, but the mere concept raises a lot of questions. How would a boundary even work? What does it separate us from? And why does the universe look very much the same everywhere if it has an edge, which is definitely not the same as everywhere else? It's a lot less parsimonious than a regular FLRW model, anyway, so absent any strong evidence I don't think it's considered very likely.

 

[Orodruin]

The usual FLRW models are infinite or finite but unbounded

I’m not sure I would use the word ”unbounded” with the meaning ”without a boundary”. Bounded has a mathematical meaning which is quite different from set boundaries. Technically the word would be a singular n-cycle, but that is not very enlightening to someone who does not know what that is. I would probably just use with/without boundary.

 

[Ibix]

I’m not sure I would use the word ”unbounded” with the meaning ”without a boundary”.

Noted.

 

[ohwilleke]

Summary:: Big Bangs Theories

Big Bang singularity can never be solved, so

Could the "big bang" have been an event where a large sum of highly-dense dark energy converted into mass, and in doing the result is like a nuclear explosion?

Could the "big bang" just have been a large sum of matter where the core becomes super dense and at the same time the core surrounded by lots and lots of other matter which is less dense, but then the core gets super small and dense, not a singularity, and then pops pushing everything outward?

One of the TV shows mentions early universe as creating the 1st elements H, He, and Li. Why Li ?

Getting back to the original question.

We don't really know how matter was created.

We do know that the mix of atomic elements in the universe is consistent with Big Bang Nucleosynthesis which assumes a state when almost all matter is in the state of protons and neutrons and they engage in high energy nuclear reactions shortly after the Big Bang to form atoms, subject to some modest tensions with the proportion of certain Lithium isotypes. This is done by taking known processes in stars and working backward to an initial state.

But we don't really know where the protons and neutrons came from, or where the electrons associated with those protons and neutrons came from, or how we got our initial mix of neutrinos.

The processes are usually called baryogenesis (for protons and neutrons) and leptogenesis (for electrons and neutrinos). The scientific literature about these processes is mostly theoretical and conjectural, since we can't create high enough energies in experiments to recreate the first moments after the Big Bang when we presume that matter was created (because we can rule out that it was created much later than that with the physics that we can test). See, e.g., "On the Origin of Matter In the Universe" (Bari 2021) (a 98 page long review of the literature on the subject).

No Standard Model of Particle Physics process links the existing mix of protons, neutrons, electrons and neutrinos to an initial state with no protons or neutrons or electrons and just pure energy. So, either that was not the initial state of the Universe at the Big Bang, or new physics beyond the Standard Model of Particle Physics gave rise to the existing situation, which presumably only come into play at extremely high energies such as those immediately after the Big Bang (a mere fraction of a second in conventional chronologies of the Universe).

In the current era's conditions, where we know that the Standard Model of Particle Physics works, matter and antimatter are always created in equal quantities. But, protons, neutrons and electrons are overwhelmingly matter and not antimatter, and we aren't aware of processes that would tilt the balance in favor of matter and against antimatter in time for Big Bang Nucleosynthesis to happen in a matter dominated universe.

 

[sysprog]

What about the fact that the top quark was found, despite its rareness (rarety/rarity), due to it being anticipated, due to its corresponding to a member of the SU(3) (super-unary, non-commutative (non-Abelian)) homology group?

 

[Drakkith]

What about the fact that the top quark was found, despite its rareness (rarety/rarity), due to it being anticipated, due to its corresponding to a member of the SU(3) (super-unary, non-commutative (non-Abelian)) homology group?

Sorry, I'm not quite sure what you're asking. Can you elaborate?

 

[ohwilleke]

What about the fact that the top quark was found, despite its rareness (rarety/rarity), due to it being anticipated, due to its corresponding to a member of the SU(3) (super-unary, non-commutative (non-Abelian)) homology group?

I fail to see the connection between this and the rest of the thread as well. Did you accidentally post in this thread rather than another one discussing a question where this observation is more pertinent?

Are you simply trying to point out that if you have a theory that tells you where to look it is much easier to find the evidence you need to prove that theory?

 

[sysprog]

Sorry, I'm not quite sure what you're asking. Can you elaborate?

I intended that question to be in response to @ohwilleke's post (#37 in this thread) $-$ but more generally, for any reader, what, in your view, might be an implication of a mathematical model being useable for prediction of the existence of a previously undetected physical reality?

 

[Drakkith]

for any reader, what, in your view, might be an implication of a mathematical model being useable for prediction of the existence of a previously undetected physical reality?

Again I'm not quite sure what you're asking, and what does this have to do with the thread topic?

 

[sysprog]

I fail to see the connection between this and the rest of the thread as well. Did you accidentally post in this thread rather than another one discussing a question where this observation is more pertinent?

Are you simply trying to point out that if you have a theory that tells you where to look it is much easier to find the evidence you need to prove that theory?

I think that it's remarkable that a mathematical model was successfully used to fill out the quark chart, and I think that the quantum chromodynamic quark model of hadron composition is germane to your remark in post #37 that "We don't really know how matter was created." I agree that we don't really know exactly how matter was created, but we know a lot more about that than we did before we sought the lighter hadrons due to what the mathematical model SU(3) suggested.

 

[pinball1970]

Noted.

Just a quicky.

Unbounded means I am not going to encounter an edge, so the surface of a sphere I will never meet an edge, I just keep walking round the surface.

If it is finite and I could fast enough but also unbounded does this mean at some point I would come back on myself? If I could travel fast enough and long enough?

This is what I have read (possibly in the Hawking book)

EDIT: From research gate (people also ask)

"According the current Cosmology our Universe is finite and unbounded, even if it is expanding. The visual analogy that is given to explain this is an expanding sphere where the galaxies are dots on it's surface."

I thought the leaning was towards infinite spatially but not temporally (from a pf thread, sorry not sure which, before xmas )

 

[Drakkith]

If it is finite and I could fast enough but also unbounded does this mean at some point I would come back on myself? If I could travel fast enough and long enough?

Quite possibly, yes. For example, if the universe is finite and unbounded with positive curvature the it would be like moving across the surface of a sphere where you could travel in one direction and eventually come back around on your original starting point.

"According the current Cosmology our Universe is finite and unbounded, even if it is expanding. The visual analogy that is given to explain this is an expanding sphere where the galaxies are dots on it's surface."

I thought the leaning was towards infinite spatially but not temporally (from a pf thread, sorry not sure which, before xmas )

The leaning is towards infinite as far as I know.

 

[Ibix]

Unbounded means I am not going to encounter an edge, so the surface of a sphere I will never meet an edge, I just keep walking round the surface.

That's the meaning I was intending, but @Orodruin says that's an incorrect use of technical language and we should say "without boundary" instead.

If it is finite and I could fast enough but also unbounded does this mean at some point I would come back on myself? If I could travel fast enough and long enough?

In a closed universe, yes. I believe you'd need to exceed the speed of light to do it, though.

I thought the leaning was towards infinite spatially but not temporally (from a pf thread, sorry not sure which, before xmas )

It can't be distinguished from flat (i.e. spatially infinite and temporally infinite in the future), but it's not certain. What "current cosmology" thinks probably depends who you talk to...

 

[sysprog]

Thanks. I have enough books.

I wasn't trying to give you suggestions for filling your library shelves; I was giving you a reference for reading material for a topic in which you seemed to be interested; please understand it as intended $-$ that book explains a lot about the formation of matter, but the topic isn't especially simple.

 

[Orodruin]

I think there are two separate questions here when one asks where matter came from. The first is where the matter came from as in where did the initial hot dense plasma come from. The second is why, when most of the baryons and leptons annihilated with their reapective anti-particles in the plasma, was there a leftover out of which the matter we see today has formed.

To the first: We do not know and it is not really part of the standard Big Bang theory to explain this and is rather an initial condition. What is true is that if you fill a universe with something energetic enough and that interacts strong enough with the standard model sector, you will end up with such a plasma at thermal equilibrium. In inflationary models, this is usually done through a reheating process where the universe is left absolutely void of things after inflation save for the remnant inflaton field whose remaining energy is then dumped into the standard model sector. Of course, inflation remains untested.

As for the second question, it is not so much a question of how the matter was created (it was created along with the rest of the hot plasma) but rather why it was allowed to remain. This is typically done through the creation of a matter-antimatter asymmetry such as a non-zero baryon or lepton number, meaning there will be just ever so slightly more particles than antiparticles. While the standard model is able to create such an asymmetry, the achievable magnitude of such an asymmetry in the standard model is much too small to explain the amount of matter we observe. Hence the need to look for new physics for this purpose.

 

[bland]

I can't remember if it was in The First Three Minutes or elsewhere, but I was particularly taken with the idea that if you imagine a magic oven that doesn't melt, and there is nothing* in that oven and all you do is keep upping the temperature, then eventually matter will burst into existence.

*no matter

 

[PeterDonis]

I was particularly taken with the idea that if you imagine a magic oven that doesn't melt, and there is nothing* in that oven and all you do is keep upping the temperature, then eventually matter will burst into existence.

There isn't "nothing" in the oven; there are quantum fields. And to raise the temperature, you need to add energy, and that energy has to come from somewhere. So you aren't bringing matter into existence out of nothing. All you're doing is adding energy to quantum fields to take them from their vacuum state, with no particles present, to higher energy states that have particles present.

 

[PeterDonis]

The "what is beyond space" statement is simply a response to the statement that space is finite.

Even if our universe is spatially finite (which is still a possibility allowed by the data although it is currently considered unlikely), there would not be anything outside it. A spatially finite universe does not have to have a boundary; the simplest model of such a universe has the spatial topology of a 3-sphere, which has a finite volume but no boundary (just as a 2-sphere has a finite area but no boundary).

Drakkith's seems to hypothesized the whole universe as a big matter with nothingness as the background.

He said no such thing. Our current model of the universe has the same average density everywhere. There is no finite region of matter with the rest being "nothingness".

As I already pointed out, only matter is finite while the background (doesn't matter what people called them space, vacuum, void, etc.) is infinite.

This is wrong.

This is not your thread and you are cluttering it with speculation and incorrect statements. You have now been banned from further posting in this thread.

 

[JandeWandelaar]

Isn't this still not yet established? Please provide reference regarding what you are designating to be the "standard view" regarding that matter. I think that we still can't say for certain that the universe is or isn't finite.

I think you're right. It's very close to flat, but just as flat-Earthers assume a globally flat Earth, flat spacers assume an infinite flat universe. But it could very well be that the curvature is very close to flat and that the universe is a closed structure, like the surface of the Earth. So if the non-flatness is very small, it could be that we just can't measure it (yet).

 

[Drakkith]

I think you're right. It's very close to flat, but just as flat-Earthers assume a globally flat Earth, flat spacers assume an infinite flat universe.

Whoa, whoa. Let's not compare cosmologists to flat-Earthers. The latter group believes the Earth is flat in spite of overwhelming evidence to the contrary. The former models the universe as flat because there's no evidence otherwise.

 

[JandeWandelaar]

Whoa, whoa. Let's not compare cosmologists to flat-Earthers. The latter group believes the Earth is flat in spite of overwhelming evidence to the contrary. The former models the universe as flat because there's no evidence otherwise.

Well, we don't know. Long time ago people thought the Earth was flat because they didn't have evidence yet it was a globe. I think we're in the same state nowadays insofar space is concerned. We assume if flat because of lack of the contrary. It could have started in an infinite space or in a small closed one. You can assume both and closed spacers are as right as flat-spacers. It depends on your theory or model which you prefer.

 

[Orodruin]

We assume if flat because of lack of the contrary.

This assertion is simply false and misleading. Nobody who works in cosmology would tell you the universe is flat at 100% certainty. That is just a misrepresentation of the current state of cosmology. What they will tell you is that if it is not flat then it has a pretty enormous radius of curvature many many times bigger than the size of the observable universe

 

[JandeWandelaar]

This assertion is simply false and misleading. Nobody who works in cosmology would tell you the universe is flat at 100% certainty. That is just a misrepresentation of the current state of cosmology. What they will tell you is that if it is not flat then it has a pretty enormous radius of curvature many many times bigger than the size of the observable universe

Exactly. That's what I meant. I used the wrong wording. Thanks.

 

[phinds]

What they will tell you is that if it is not flat then it has a pretty enormous radius of curvature many many times bigger than the size of the observable universe

And they might add that of ALL the infinite values it COULD have, the fact that it is flat within our ability to measure it is just one HELL of a co-incidence if it's not actually flat. That's not any kind of proof but it sure is suggestive.

 

[JandeWandelaar]

And they might add that of ALL the infinite values it COULD have, the fact that it is flat within our ability to measure it is just one HELL of a co-incidence if it's not actually flat. That's not any kind of proof but it sure is suggestive.

Why would the fact that it's flat within our ability to measure be a concidence if space is closed with a huge radius? It would be logical then that we measure flatness within our ability. We couldn't measure non-flatness then. So it suggests that the radius is huge.

 

[horacio torres]

It is the "standard view" these days that our Universe is infinite. If this is so then it was infinite when it came into existence. Weird, eh?

Our visible universe is very homogenous, which means on a large scale it is pretty much the same everywhere. So when it first came into being it was extremely dense everywhere. I don't really know, but I'd suppose that it is hard to say what it was. After a while it cooled down enough to become matter and anti-matter. Mostly these annihilated one another into energy, mysteriously leaving a residue of matter. I suppose it was a quark-gluon plasma or something even more exotic. I don't know when the universe cooled enough for protons and electrons to appear en masse. The universe was still denser than the core of our sun so some of these particle fused into helium and lithium ions. After 300,000 years things had cooled enough that these ions could form atoms.

My main point is that matter appeared before atoms and ions made the scene.

the statement ¨Our visible universe is very homogenous, which means on a large scale it is pretty much the same everywhere¨

It means that we are like bacterium compare with the all universe that we actual see it is an real big one space with spot every 300 mm Years light of matter and energy.Horacio

 

[phinds]

Why would the fact that it's flat within our ability to measure be a concidence if space is closed with a huge radius?

To me, that question reads exactly as follows "if the universe were almost flat why would it be a coincidence that it is almost flat?"