Origin of matter

Mark M

There was no 'bang'. The 'big bang' refers to the hot, dense state the entire universe was in. Not some kind of explosion from a point in space. The entire universe was filled with a hot soup of radiation and plasma. As space expanded from every point, everything cooled, radiation redshifted, and plasma became gas. More dense regions of gas pulled in the less dense regions with gravity, which then became dense enough to halt expansion within them. The space in between these clouds continued to expand, separating them. They then developed into galaxies.

That's the (very) general picture.

I'm not sure where you got this number. It's much more ridiculously small than 2 to 1. Kolb/Turner estimate there were 30 million and one quarks for every 30 million anti-quarks.

See this page:

http://math.ucr.edu/home/baez/physic...yogenesis.html

Naty1

comment: lots of goofy posts in this thread; Drakkith's seem on target.

This explanation does give some good insights.

Here is a closely related one I saved from another discussion in these forums:

Moving, on and back to the OP:

No one knows with reasonable certainty what started the big bang, nor cyclic bangs if they exist, for that matter. It is extremely unlikely that any matter was at the start of any bangs.....somehow radiation/energy was created...likely space and perhaps time too. Perhaps a random statistical quantum fluctuation started our universe, perhaps something else. All our models start just AFTER such a start.

One good discussion about particles/matter in these forums is here:

What is a particle:
http://www.physicsforums.com/showthread.php?t=386051
and another:

http://www.physicsforums.com/showthread.php?t=590798

There are three ways one can 'produce' particles: accelerate yourself, accelerate spacetime, or accelerate a cosmological horizon!!

One of our resident experts made this observation which I like because it also provides insights:
A particle or matter is a quanta of a quantum field....a concentration of energy,momentum,etc. Regarding the big bang, it is possible quantum fluctuations in the inflationary vacuum become quanta [particles] at super horizon scales. Particle production via changing gravitational fields and expansion is believed a real phenomenon. It seems that expansion of geometry itself, especially inflation, can produce matter.

We're familiar with other theoretical cases where geometric circumstances create real (not virtual) particles , like Hawking radiation at a BH horizon and Unruh radiation caused by an accelerating observer. With the Unruh effect, it is theorized that two adjacent observers, one inertial and one accelerating will measure different temperatures and make different counts of particles. In other discussions in these forums, there are theories that at the Hubble radius the accelerating Hubble Horizon is sufficient for the production of particles.

A distinction between particles and mass would be that a particle might be massless, like the photon, while others would have mass, like an electron or W boson. The difference is that a certain scalar field is sufficient to break symmetry in some cases via a 'false vacuum' transition: It is theorized that is the Higgs field which is part of the Standard Model of PArticle Physics and is powered by a vacuum energy.


According to Wikipedia, Nobody understands the precise nature of the Higgs mechanism either but there are mathematical models. MarkM gives a description in Post #12, here:

http://www.physicsforums.com/showthread.php?t=621236

PhanthomJay

Hawking continues to be ignored for some reason . Gravity is energy and energy is mass.
-Hawking, "The Grand Design".

Gravity...Hawking's god...creator of all both seen and unseen.

Now if we could just figure how gravitational energy originated..........

Kristiandhd

but thats during the big bang. not before that, the radiation is as far as i know only reflectan of the time during and after the big bang
though matter could have been as sub atomic particle or something else before, spread all across the universe not condense and hot, over time it could have condense as if it were a newly forming star.
it is agreed that all matter was condense. but was there an infinite space-time out side of that? and wouldn't it be unlikely that we were the only big bang in the universe, if it is infinite.?
though for us our observable universe is more than immensely big, for and infinite space-time this would all just be another speck of dust.
now if space-time isn't eternal then matter appeared from nowhere, since matter can not be where space-time isn't, it could have been a billionth of a nano second after space, it still appeared from nowhere.

just for fun
it's not about what's probable, but about what is possible.

Mark M

Radiation dominated the very early moments after the big bang. However, particle pair production gave rise to the particles of the Standard Model, which then proceeded to begin big bang nucleosynthesis very shortly thereafter.

No. The big bang wasn't a point in space. It was NOT an explosion. The ENTIRE universe was filled with radiation and a hot dense plasma. Space itself underwent metric expansion, so that the radiation redshifted and cooled, and the matter became gas. Dense regions of the gas pulled in the less dense regions, becoming galaxies. This is why we observer our universe today to be homogeneous.

This also incorrect. The universe was extremely dense, but as stated above, this dense plasma was everywhere.

Firstly, the big bang happened everywhere. Secondly, there is no such thing as 'outside' of the universe. The universe may be infinite, or it is simply or non-simply connected if finite.

One again, the big bang is a moment in time, not a point in space. If the universe is infinite, then it still occurred everywhere.

It seems you have quite a few misconceptions about cosmology. I would strongly recommend reading this article:

http://www.mso.anu.edu.au/~charley/p...DavisSciAm.pdf

Also, you should take a look at this page afterwords:

www.phinds.com/balloonanalogy

twofish-quant

Actually we can. It's not a big deal for physicists to create protons and electrons. Happens all of the time at CERN. You can call someone on the phone and say "Jim, I want you to make me a proton" and someone flips a switch and it happens.

We can get into a useless discussion about whether it's possible to be absolutely certain of anything, but it's possible to be as certain about the events of the early universe as it is to be certain about the events of say the American Revolutionary War or World War II. Figuring out the early universe is no different than figuring out the live history of George Washington, and we probably have *more* evidence for certain parts of the early universe than we do about some parts of Washington's life.

I know that Time Square exists because I've been there. I know that the big bang happened because I've seen pictures of it. Speed of light delays things, so you can take a microwave telescope and see the big bang. Since you can actually see the big bang *right now* it's actually easier in some ways to figure out how it works than to figure out the life of George Washington.

One of my goals is to demystify cosmology. It's not so weird thing. You can see the big bang as easily as you can see the plant Pluto.

Kristiandhd

i didn't mean outside of the universe, and how can matter occupy the entire universe if it is infinite, and if space-time appears from nowhere, as it is expanding, why can't matter come from nowhere.
and as i stated i said maybe at hydrogen or a more basic type of matter.
and i believe in the big expansion, its proven and observable, but the question was about before it, and where the matter came from. i think it appeared from nothing, specially if the space-time is not eternal or has always been around, since if it started at some point, space had to appear before matter could occupy it.

QuantumHop

As I understand it matter is kind of borrowed at the expense of gravity, so if gravity was negative energy and matter was positive and you add them both together you end up with nothing.

Drakkith

Matter doesn't occupy every fraction of space within the universe, it is merely spread out approximately homogenous everywhere. (Meaning that it clumps together into galaxies and stars and such, but on the largest scales it is homogenous.) If the universe is infinite in extent, and the average density of matter is the same everywhere, then there is an infinite amount of matter spread approximately homogenously throughout the entire universe.

Matter was not created from nothing. All the matter in the universe today was created early in the universe by interacting high energy photons. Where the ultimate origin of all of this was is unknown and probably isn't capable of being known. Any talk of where spacetime came from is pure speculation at this point.

phinds

yes, but not for long

Kristiandhd

but if you state that it was dense in the beginning through out the whole universe, and space-time being infinite for it to be spread out across some what evenly through space-time then there would be an infinite amount of matter? for if it is finite there would be an infinite amount of empty space time.
and isn't there multiple theories about where matter came from and coming from nothing is one of them. one being the collapse of other dimensions, and i think one where waves in space time collided to make it. (though i find it unlikely since what created the wave in the first place.)

but do you agree that if space started, and hasn't been around forever, then matter had to have come from nothing since space had to appear first for matter to then occoupy it, since matter can't simultaniously appear for that would mean it appear nowhere since there would be no space time for it appear in. correct me if i'm wrong but isn't that the idea of the singularity that the universe just appeared.

Kristiandhd

and i accept my ignorance in my point of view, i'm merely trying to understand it better, you seem 100% certain of your beliefs, and maybe up until now you are as correct as our current knowledge allows us to be. i don't know but if you are then i'll try and learn.

Drakkith

There is only 1 scientific theory that is accepted as the origin of matter and that is the standard Big Bang theory that states that the universe was once very hot and very dense and expanded and cool from there. It doesn't state whether spacetime is infinite or finite, and both are possibilities that would fit just fine within the theory. If the universe is inifinite in size it is logical to think that there is an infinite amount of matter. If the universe is finite in size then the reverse is true and that there is only a finite amount of matter. Do we know that an infinite universe must contain an infinite amount of matter? No, but if it doesn't then we would have to rework some of our ideas. We simply don't know at the moment, but since the observable universe is seen to have lots of matter evenly distributed throughout it makes sense to think that the rest of the universe is the same way.

As for space being around forever, I can't comment on that, as anything I could say would be pure speculation. I have no idea if the universe came from "nothing" or not, or if there was really a singularity or not. I personally want to say that it makes no sense that we come from nothing, but the notion that the universe has existed in some form or fashion for an infinite amount of time is just as confusing and mind blowing as it coming from "nothing".

phinds

I think you misunderstand the scientific term "singularity" and are taking it to mean something specific physically. That's not what it means. What it MEANS is "the place where our models break down and we have no idea what was happening".

As Drakkith said, the big bang model says NOTHING about what what there at the "singularity" because the word just means "we don't know".

atlasman84

i did not clear picture about antimatter. is't only a little or much more than matter?

Drakkith

I'm sorry I can't understand you. Could you try to be a bit clearer with what you want to know?

notuhjim

Assuming that the mathematical theorems we discover or invent,
do reflect a "rich platonic world that is not of our making", what then?

Maybe the space-time of our world is funded somehow by a natural event
or an unholy failure in that robust Platonic world
(where anything which can happen does happen, and it happens all at once).

Space-time emerges in the absence of number, it begins where the numbers stop,
and our stars as well as ourselves are reassembling cannibalized bits of ruined integer meat,
and our world is as an after life of that that one,
and our doing mathematics, among other things, a form ancestor worship.