The Big Bang happened everywhere

[substitutematerials]

All observable space emerged from the same hot dense point, and the universe has no center or preferred direction. You can't point in a direction and say, "the universe began over there." It began on the tip of a flea's nose in France, and in a far corner of Andromeda. We can all say "I am standing right where the universe began 13.7 billion years ago."

 

If we agree on that, my question is: Why can't we apply this logic to events that weren't global in extent like the big bang, but only occurred in a isolated region of space. Let's imagine that a star formed in the early universe, when the scale factor was 1/100 of present. Could we then say that somewhere out there, a region of space exists with a radius 100 times larger than the ancient star's radius, where that star had once formed. People in this region could say, "I am standing where that ancient star formed."

 

[MigL]

The driving force behind expansion is actually very weak.

Once an area of space reaches a mass-energy density threshold, gravitational coupling of the mass-energy easily overcomes the expansion. It is only the very low density areas between galactic clusters, where space-time is nearly flat, that expansion is dominant.

An area which contains a star would certainly not expand 100x.

[substitutematerials]

The driving force behind expansion is actually very weak.

Once an area of space reaches a mass-energy density threshold, gravitational coupling of the mass-energy easily overcomes the expansion. It is only the very low density areas between galactic clusters, where space-time is nearly flat, that expansion is dominant.

An area which contains a star would certainly not expand 100x.

 

Thanks MigL, I see that a star would be above the density necessary to reverse expansion. Revise my question then-- to a region in space where a lone proton and electron once combined, in a region below the critical density. Could the idea apply to this situation, that one region of space has become many? Could people in a much larger present region of space now say, "I am standing where that particular proton and electron once combined?"

 

Also to pick bones, isn't it true that expansion throughout history has been primarily inertial? So we don't need to refer to the force behind expansion, because the universe has mostly coasted to its present size. Dark energy is a force that drives expansion, but it has only become significant in the latter half of history, right?

[Strange]

If we agree on that, my question is: Why can't we apply this logic to events that weren't global in extent like the big bang, but only occurred in a isolated region of space.

 

 

The big bang happened (and is still happening) in the entire universe, not at some localised point within it.

[Delta1212]

 

Thanks MigL, I see that a star would be above the density necessary to reverse expansion. Revise my question then-- to a region in space where a lone proton and electron once combined, in a region below the critical density. Could the idea apply to this situation, that one region of space has become many? Could people in a much larger present region of space now say, "I am standing where that particular proton and electron once combined?"

 

Also to pick bones, isn't it true that expansion throughout history has been primarily inertial? So we don't need to refer to the force behind expansion, because the universe has mostly coasted to its present size. Dark energy is a force that drives expansion, but it has only become significant in the latter half of history, right?

Expansion is all down to the metric expansion of space. For it to be inertial would require it to be the result of galaxies moving away from each other through space rather than space expanding between galaxies (or really galactic super-clusters). Dark Energy is necessary to explain the acceleration of this process (which I believe is more recent yes), but not the expansion itself.

[MigL]

The driving force ( if it can be called that ) would be negative pressure due to vacuum energy.

This vacuum energy would have settled and subsequently fallen from false zero levels at one or more symmetry breaks in the early stages of the universe when the forces separated, and can be used to explain the inflationary period(s). This vacuum energy can be modelled by Einstein's Cosmological Constant.

 

As to the reason for the recent ( few bil yrs ) change that accounts for the speed up of expansion, I don't believe anyone knows yet.

( Mordred could give a better explanation, along with several linked papers )

Edited October 24, 2016 by MigL

[Mordred]

Sounds like a request. I will post a detailed explanation after work later today.

Lol busy day. Anyways there is a handy formula.

 

[latex]H_z=H_o\sqrt{\Omega_m(1+z)^3+\Omega_{rad}(1+z)^4+\Omega_{\Lambda}}[/latex]

 

What this formula describes is

1) the rate of expansion today to the rate of expansion previously.

2) the evolution of density of matter, radiation and Lambda.(cosmological constant)

 

There was three main eras. Radiation dominant, matter dominant and Lambda dominant. Prior to CMB was the radiation dominant (including inhlation).

Then as the universe expanded the rate of expansion was matter dominant (a matter dominant universe still expands) The reason is as matter forms into large scale structures the global density decreases.

See the matter term under the equation above. This means gravity has a lower influence on a global scale.

Eventually the influence of radiation and matter decreases. Again see formula above.

However the Lambda term does not decrease in density as matter and radiation does.

 

So once the Lambda term becomes dominant on the above equation we enter our Lambda dominant era at roughly 6.8 billion years of age for our universe.

 

It is the detail of Lambda not decreasing in density as the volume increases that causes the accelerating expansion. However just for the additional increase to expansion without the cosmological term.

 

The first two articles will detail the Deceleration equation, the fluid equation and the FLRW metric in regards to expansion.

The last two links details the thermodynamic aspects in greater detail.

 

http://arxiv.org/pdf/hep-ph/0004188v1.pdf :"ASTROPHYSICS AND COSMOLOGY"- A compilation of cosmology by Juan Garcıa-Bellido

http://arxiv.org/abs/astro-ph/0409426 An overview of Cosmology Julien Lesgourgues

http://arxiv.org/pdf/hep-th/0503203.pdf "Particle Physics and Inflationary Cosmology" by Andrei Linde

http://www.wiese.itp.unibe.ch/lectures/universe.pdf:"Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis

Edited October 25, 2016 by Mordred

[substitutematerials]

Sounds like a request. I will post a detailed explanation after work later today.

Lol busy day. Anyways there is a handy formula.

 

[latex]H_z=H_o\sqrt{\Omega_m(1+z)^3+\Omega_{rad}(1+z)^4+\Omega_{\Lambda}}[/latex]

 

What this formula describes is

1) the rate of expansion today to the rate of expansion previously.

2) the evolution of density of matter, radiation and Lambda.(cosmological constant)

 

There was three main eras. Radiation dominant, matter dominant and Lambda dominant. Prior to CMB was the radiation dominant (including inhlation).

Then as the universe expanded the rate of expansion was matter dominant (a matter dominant universe still expands) The reason is as matter forms into large scale structures the global density decreases.

See the matter term under the equation above. This means gravity has a lower influence on a global scale.

Eventually the influence of radiation and matter decreases. Again see formula above.

However the Lambda term does not decrease in density as matter and radiation does.

 

So once the Lambda term becomes dominant on the above equation we enter our Lambda dominant era at roughly 6.8 billion years of age for our universe.

 

It is the detail of Lambda not decreasing in density as the volume increases that causes the accelerating expansion. However just for the additional increase to expansion without the cosmological term.

 

The first two articles will detail the Deceleration equation, the fluid equation and the FLRW metric in regards to expansion.

The last two links details the thermodynamic aspects in greater detail.

 

http://arxiv.org/pdf/hep-ph/0004188v1.pdf :"ASTROPHYSICS AND COSMOLOGY"- A compilation of cosmology by Juan Garcıa-Bellido

http://arxiv.org/abs/astro-ph/0409426 An overview of Cosmology Julien Lesgourgues

http://arxiv.org/pdf/hep-th/0503203.pdf "Particle Physics and Inflationary Cosmology" by Andrei Linde

http://www.wiese.itp.unibe.ch/lectures/universe.pdf:"Particle Physics of the Early universe" by Uwe-Jens Wiese Thermodynamics, Big bang Nucleosynthesis

HI Mordred

 

Thanks, this is great information. I am familiar with a similar equation to calculate lookback time (it won't let me post the equation, says the latex image is too large), which I learned as the Hogg Equation. It makes sense to me from this expression that the universe would go through the eras you mention, simply because the density of each term has a different exponent. I'll definitely check out these links.

 

In my original question, I was trying to get at this question: Is it correct to think of one finite region of space becoming many? Take one cubic meter of expanding space. Does it become many cubic meters of adjacent space in its expansion? Is there any meaning to the shared lineage of these newly-minted meters? Could multiple future observers in the new larger volume somehow detect that they are occupying what was once the same space?

Edited October 25, 2016 by substitutematerials

[imatfaal]

[latex]t_L=\frac{1}{H_0} \int_{0}^{z}\frac{dz'}{(1+z')\sqrt {\Omega(1+z')^3+\Omega_k(1+z')^2+\Omega_{\lambda}}}[/latex]

Just checking our latex is working - I presume this is the equation you were referring to? If you are using a latex generator rather than just typing it in the old fashioned way maybe it is putting in some spare characters

[Mordred]

 

In my original question, I was trying to get at this question: Is it correct to think of one finite region of space becoming many? Take one cubic meter of expanding space. Does it become many cubic meters of adjacent space in its expansion? Is there any meaning to the shared lineage of these newly-minted meters? Could multiple future observers in the new larger volume somehow detect that they are occupying what was once the same space?

No, one space will not overlap another region as each region expands equally. (assuming not gravitationally bound).

 

Each region will remain their own seperate locality. Much like the surface of the balloon. As far as new volume, other than thermodynamic applications it has no meaning other than new volume. For an analogy the additional volume as you blow up the balloon only affects the average density/temperature and pressure of the air. However the additional volume is essentially indistinguishable from a previous region.

 

(side note if you quote our posts, you can see how Imatfaal and I are doing the latex structure)

Edited October 25, 2016 by Mordred

[substitutematerials]

[latex]t_L=\frac{1}{H_0} \int_{0}^{z}\frac{dz'}{(1+z')\sqrt {\Omega(1+z')^3+\Omega_k(1+z')^2+\Omega_{\lambda}}}[/latex]

Just checking our latex is working - I presume this is the equation you were referring to? If you are using a latex generator rather than just typing it in the old fashioned way maybe it is putting in some spare characters

Yes that is the equation I was referring to, and I was using a generator. I will try to handcraft them in the future. Also is there a preview button I'm missing?

No, one space will not overlap another region as each region expands equally. (assuming not gravitationally bound).

Each region will remain their own seperate locality. Much like the surface of the balloon. As far as new volume, other than thermodynamic applications it has no meaning other than new volume. For an analogy the additional volume as you blow up the balloon only affects the average density/temperature and pressure of the air. However the additional volume is essentially indistinguishable from a previous region.

(side note if you quote our posts, you can see how Imatfaal and I are doing the latex structure)

Well I think that answers my question, thanks a lot Mordred. The answer is then no-- present regions of space do not share a lineage, I.e. 2 regions cannot be said to have emerged from one. Back to the original statement then-- wouldn't it be wrong to say "the Big Bang happened everywhere?

[StringJunky]

....wouldn't it be wrong to say "the Big Bang happened everywhere?

No, because everywhere inflated; all adjacent points in the universe gained distance from each other.

[imatfaal]

Yes that is the equation I was referring to, and I was using a generator. I will try to handcraft them in the future. Also is there a preview button I'm missing?

 

Well I think that answers my question, thanks a lot Mordred. The answer is then no-- present regions of space do not share a lineage, I.e. 2 regions cannot be said to have emerged from one. Back to the original statement then-- wouldn't it be wrong to say "the Big Bang happened everywhere?

 

"Also is there a preview button I'm missing?" - yes. If you click "more reply options" you get more reply options (not surprising really), ability to attach files, add polls, and post preview. The latex is a bit shonky here at times but not too bad. There is a tutorial over in maths and people like Sensei and Mordred seem to have Latex as a second language (or third or fourth) so you can always ask questions in Suggestions Forum

[Mordred]

There is a tutorial over in maths and people like Sensei and Mordred seem to have Latex as a second languagem

Lots of practice lol, some of my more complex posts took several hours to get all the latex the way I wanted it.

Yes that is the equation I was referring to, and I was using a generator. I will try to handcraft them in the future. Also is there a preview button I'm missing?

 

Well I think that answers my question, thanks a lot Mordred. The answer is then no-- present regions of space do not share a lineage, I.e. 2 regions cannot be said to have emerged from one. Back to the original statement then-- wouldn't it be wrong to say "the Big Bang happened everywhere?

No, because everywhere inflated; all adjacent points in the universe gained distance from each other.

To add to this, as our Observable universe portion started out at roughly a Planck length. Coupled with the cosmological principle. It only makes sense to state the BB happened everywhere.

 

After all our universe surrounds us if you look far enough back in time. In every direction you look you would see the BB.

 

Assuming we could look this far back, which we can't due to CMB and the previous dark ages. (period when the average mean free path of a photon was approximately 10^-32 metres.)

Edited October 26, 2016 by Mordred

[substitutematerials]

After all our universe surrounds us if you look far enough back in time. In every direction you look you would see the BB.

 

Assuming we could look this far back, which we can't due to CMB and the previous dark ages. (period when the average mean free path of a photon was approximately 10^-32 metres.)

 

I get this. But then I would then be inclined to say, "the big bang happened in every direction." Not "everywhere." I am not occupying space formerly occupied by the big bang. That spatial coordinate would be some horizon beyond the observable horizon.

[StringJunky]

 

I get this. But then I would then be inclined to say, "the big bang happened in every direction." Not "everywhere." I am not occupying space formerly occupied by the big bang. That spatial coordinate would be some horizon beyond the observable horizon.

Yes you are; it happened here, there and everywhere.

[substitutematerials]

Yes you are; it happened here, there and everywhere.

If this is the case, then my second conjecture must also be true- that local regions have also subdivided. I am standing where some past event occurred, prior to this region becoming gravitationally bound, and another distant observer may be occupying space with the same shared lineage. I can't see how you can have one statement and not the other.

 

Do you guys understand what I am hung up on here?

[Strange]

If this is the case, then my second conjecture must also be true- that local regions have also subdivided. I am standing where some past event occurred, prior to this region becoming gravitationally bound, and another distant observer may be occupying space with the same shared lineage. I can't see how you can have one statement and not the other.

 

Do you guys understand what I am hung up on here?

 

I think you are hung up on an incorrect mental model of space as "stuff" that stretches or multiplies.

[Airbrush]

"The Big Bang happened everywhere".

 

False!

 

The word "everywhere" assumes a universe that is INFINITE in size. In a finite-sized, bounded universe "everywhere" includes outside the boundaries of the FINITE universe, beyond our big bang. Maybe our big bang is only one of an infinite number of big bangs in a larger multiverse.

 

To be correct the statement should be "The big bang happened everywhere, IF the universe is INfinite in size."

 

Also to capitalize Big Bang implies something special about the big bang, like it is the only one that could happen. We don't know that, and maybe never will know that.

Edited October 26, 2016 by Airbrush

[StringJunky]

"The Big Bang happened everywhere".

 

False!

 

The word "everywhere" assumes a universe that is INFINITE in size. In a finite-sized, bounded universe "everywhere" includes outside the boundaries of the FINITE universe, beyond our big bang. Maybe our big bang is only one of an infinite number of big bangs in a larger multiverse.

 

To be correct the statement should be "The big bang happened everywhere, IF the universe is INfinite in size."

 

Also to capitalize Big Bang implies something special about the big bang, like it is the only one that could happen. We don't know that, and maybe never will know that.

How long have you been coming to this site? Don't you listen to anything? Take any volume or area, regardless of whether it is bounded, unbounded, finite or infinite or some combination of the first two or second two, "everywhere" is any part of that volume or area.

[Airbrush]

"Everywhere" is located at any point in that FINITE volume (not "area" because AREA refers to 2 dimensions - review your geometry), and beyond that.

 

To use the word "everywhere" refers also to what exists outside our observable universe. We don't know about that, the big bang may have an edge or not.

How long have you been coming to this site? Don't you listen to anything?

 

No I don't listen to ANYTHING. Are you satisfied?

Edited October 26, 2016 by Airbrush

[Strange]

The word "everywhere" assumes a universe that is INFINITE in size.

 

 

No it doesn't. Why would you think that? It means "everywhere in the universe (however big that is)".

 

 

In a finite-sized, bounded universe "everywhere" includes outside the boundaries of the FINITE universe, beyond our big bang.

 

There is no "outside the boundaries of the finite universe". Because there are no boundaries.

 

 

 

Also to capitalize Big Bang implies something special about the big bang

 

I agree it should not be capitalised (but not for that reason).

To use the word "everywhere" refers also to what exists outside our observable universe.

 

 

Correct. It is assumed that the universe outside the observable universe is largely the same. There is no reason (and no evidence) to think otherwise.

[Delta1212]

"Everywhere" is located at any point in that FINITE volume (not "area" because AREA refers to 2 dimensions - review your geometry), and beyond that.

 

To use the word "everywhere" refers also to what exists outside our observable universe. We don't know about that, the big bang may have an edge or not.

 

 

No I don't listen to ANYTHING. Are you satisfied?

There is no where outside of the universe to be part of that every.

[substitutematerials]

 

I think you are hung up on an incorrect mental model of space as "stuff" that stretches or multiplies.

 

This could certainly be my hangup. But at the same time, I feel like the statement about the big bang happening everywhere rests on such a premise: that the original planck length volume has 'stretched' to the present size of the universe, whatever size that may be. A coordinate system could be drawn in the original volume which could undergo transformation to present coordinates.

[Strange]

 

This could certainly be my hangup. But at the same time, I feel like the statement about the big bang happening everywhere rests on such a premise: that the original planck length volume has 'stretched' to the present size of the universe, whatever size that may be. A coordinate system could be drawn in the original volume which could undergo transformation to present coordinates.

 

 

That sounds roughly correct.