Singularity Question

[dylan]

I just have a quick question about the singularity that theoretically was the universe before the Big Bang. I don't know the exact calculations, but it seems like the singularity would have an escape velocity far above the speed of light. If so, how did matter escape from the singularity? (I'm not talking about space; space is massless, and so can travel past the speed of light without violating general relativity, right?). I had a theory about it, but I don't have the skills to tell if it's possible, let alone prove/ disprove it. Thanks in advance.

[jackson33]

Under BBT, as I understand it, Laws of Physics (special relativity etc) did not exist until after BB.

 

The singularity, suggest, space was part of it. Nothing escaped, but expansion of, began and continues today. Space then part of...

 

Give your idea, which would allow a directed response. Big Bang is very complicated....

[Martin]

Under BBT, as I understand it, Laws of Physics (special relativity etc) did not exist until after BB.

...

 

?

 

Where are you getting that?

 

I don't know of any professionally researched theory called "BBT", no scholarly books about it, no journal papers about it. You must mean "Big Bang Theory".

 

There is the field of COSMOLOGY which talks about an expanding space model.

Some versions of cosmology go back before the start of expansion (before the big bang) and others do not.

 

No versions of cosmology that I know of actually state that special relativity doesnt apply prior to big bang. Either they simply dont say anything about that moment, or they run the laws of physics back before the big bang----something that is becoming increasingly common in today's research.

 

I'm not talking about popularized accounts written for the general public. I follow the professional literature in cosmology and quantum cosmology fairly closely, what gets published in peer-review journals. So that's what I'm mainly talking about. If you want links to recent papers, please ask.

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I just have a quick question about the singularity that theoretically was the universe before the Big Bang. I don't know the exact calculations, but it seems like the singularity would have an escape velocity far above the speed of light. If so, how did matter escape from the singularity? (I'm not talking about space; space is massless, and so can travel past the speed of light without violating general relativity, right?). I had a theory about it, but I don't have the skills to tell if it's possible, let alone prove/ disprove it. Thanks in advance.

 

No scientist that I know of says that the singularity represents a physical reality. By definition, a singularity is not something occurring in nature. It is just a place where a manmade theory breaks down. As such it defines a boundary past which some manmade theory cannot be pushed because it blows up, fails to apply, fails to compute meaningful numbers, or fails in some other way.

 

So vintage 1915 Gen Rel happens to fail at the start of expansion.

 

there are newer models which don't fail. So they don't have a singularity at the start of expansion. You can put the model in a computer and run it backwards in time and it will not blow up. It will just continue back in time before the bigbang moment. Typically what you get back before there is a collapsing region of spacetime. Very roughly similar to ours except that it is collapsing and ours is expanding.

 

this is being studied a lot. People try varying the parameters and running different versions, adding stuff, changing stuff, to see what the results are.

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So don't imagine the singularity as a physical thing that actually happened. But you asked about expansion speeds

"...space is massless, and so can travel past the speed of light without violating general relativity, right?."

in fact General Relativity allows for the distance between two massive bodies to increase at thousands of times the speed of light.

you seem to think that only massless regions of space can recede from each other at superluminal speeds.

 

the older theory, 1905 SPECIAL relativity, has a speed limit of c in it, and that applied to massless as well as massive stuff. But don't let that fool you into thinking that GENERAL relativity, the 1915 theory, has the same kind of restriction on recession speeds. Recession speed, in Gen Rel, is different from the motion of something that is going past you.

 

the Lineweaver SciAm article has some stuff about that.

 

So anyway, there is no problem with escape velocities, the instant that expansion started

massive bodies can reced from each other at thousands of times c, as required by General Relativity

 

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to take a more moderate example, you know we are constantly receiving the CMB signal, making maps of the microwave sky etc etc.

the matter that emitted that signal was receding at about 60 times the speed of light from the matter that eventually became you and me, at the time the light was emitted. and it is now, as of today, receding at around 3.3 c.

 

when it emitted the light we are now getting as microwaves, it was 40 million LY away from (what became) us and receding at 60c

and it is now around 45 or 46 billion LY away from us and receding at 3.3 c.

 

that is matter receding from matter. it doesnt have to do with masslessness and empty space. it is commonplace. we get it all the time

and it is the basis of some of the best astronomy being done today.

[dylan]

Thanks for the clarification about recession speeds, Martin, it seems to make sense for me.

 

"If you want links to recent papers, please ask."

I don't know if I have enough understanding of theoretical science to read through peer- reviewed papers, but if you have links to some of them, than I might as well try.

 

 

 

If you guys are interested my theory, I guess that I will explain it, although keep in mind that it's a fairly basic, and I expect that it will have some massive holes in it. Here it goes:

In my theory, I'm accepting that m-theory (and therefore string theory) is correct. As I understand it, the membranes in m-theory have the possibility of being gigantic, and membranes/ other universes also have the possibility of having different physics from each other. If two membranes collided with something like our singularity (at the time, I was still thinking of a singularity as a physical object) in the center, it could produce a whole lot of energy, and the conflicting laws of physics from the membranes would make it so that our laws of physics were very badly distorted for a brief period of time, allowing for anomalies that would break general relativity. After this period, the physics of our universe became normalized, resulting in the general relativity that we have now. Feel free to debunk/ comment on it

[Martin]

 

"If you want links to recent papers, please ask."

I don't know if I have enough understanding of theoretical science to read through peer- reviewed papers, but if you have links to some of them, than I might as well try.

 

Hi dylan, I'm guessing you want links to recent papers about conditions that could have preceded the big bang. (If you had something else in mind, let me know.)

 

the reason I think that is the context. I was saying this:

Either they simply dont say anything about that moment, or they run the laws of physics back before the big bang----something that is becoming increasingly common in today's research...

... So that's what I'm mainly talking about. If you want links to recent papers, please ask.

 

I'm going to be long winded about this. First, before I recommend any specific paper, i will make sure you know how to use the ARXIV search engine.

 

One of the leading people in this field (quantum cosmology, getting past the singularity) is Abhay Ashtekar. So, go here

http://arxiv.org/find

 

and type Ashtekar into the author window and you get links to all his papers

http://arxiv.org/find/all/1/au:+Ashtekar/0/1/0/all/0/1

 

so you look down the titles (which may be discouraging because they mostly sound very technical) and maybe this one catches your attention

http://arxiv.org/abs/gr-qc/0607039

Quantum Nature of the Big Bang: Improved dynamics

Abhay Ashtekar, Tomasz Pawlowski, Parampreet Singh

published in Physical Review D

(Submitted on 10 Jul 2006)

 

"An improved Hamiltonian constraint operator is introduced in loop quantum cosmology. Quantum dynamics of the spatially flat, isotropic model with a massless scalar field is then studied in detail using analytical and numerical methods. The scalar field continues to serve as 'emergent time', the big bang is again replaced by a quantum bounce, and quantum evolution remains deterministic across the deep Planck regime..."

 

that link gives a summary of the article called its ABSTRACT and it also gives a PDF link to the whole article.

 

that is just a sample. what you can do is go down the list of titles for yourself, and if you see some that you think might be helpful, look at their one-paragraph abstracts. then if you see a summary that looks promising, download the PDF.

 

THEN the problem is to get something out of it without getting bogged down in technical detail. Usually there is a page or two of introduction at the beginning and a conclusion section at the end, describing what they are doing in non-mathematical generalities.

 

I am not guaranteeing that you will find anything here that is accessible. It may all be too jargon-laden. And I will try to get back later with some specific suggestions (maybe not peer-review journal articles) if I can think of some. But this at least puts you in immediate contact with the original sources. You can get a taste of what the research papers in this field are like.

 

Another great search engine is Spires at Stanford.

http://www.slac.stanford.edu/spires/

 

Also keep in mind that this is a new field and the theoretical models are untested.

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Here's something to try:

Go to Spires

http://www.slac.stanford.edu/spires/

and type this into the search window

FIND K QUANTUM COSMOLOGY AND DATE > 2005

 

It means keyword=quantum cosmology, and published after 2005. And be sure to set Sort to "Approx. Citation Count".

If you don't set sort, the default will give you 200 articles in random or chronological order. If you select "approx. citation count"

then what you get first will be the articles that have proven useful to other researchers and so have been cited as references by them.

 

the most highly cited people in quantum cosmology are Bojowald, Ashtekar, and Parampreet Singh. Singh is a young guy who has been co-authoring with both of the two leaders, so there is a kind of coat-tail effect.

 

Spires is great because of the "Approx. citation count" option which acts like a filter, helping you to find the most important research articles

and to identify the leaders in any given field of research. It doesn't do the whole job for you, but it helps.