The Big Bang Theory: Was There No Space?

[Kevin_Axion]

Thanks for the awesome links! I just find it fascinating that research of that magnitude is occurring fourty minutes away from my house - Perimeter Institute.

 

[physics_931]

His paper on it is dated 2001.

...

By 2001 Bojowald was on his own and at Penn State. He had written some LQC papers but not yet the big bounce. The first LQC big bounce paper was:

http://arxiv.org/abs/gr-qc/0102069
Absence of Singularity in Loop Quantum Cosmology
Martin Bojowald
4 pages, 1 figure
(Submitted on 14 Feb 2001)
"It is shown that the cosmological singularity in isotropic minisuperspaces is naturally removed by quantum geometry. Already at the kinematical level, this is indicated by the fact that the inverse scale factor is represented by a bounded operator even though the classical quantity diverges at the initial singularity. The full demonstation comes from an analysis of quantum dynamics. Because of quantum geometry, the quantum evolution occurs in discrete time steps and does not break down when the volume becomes zero. Instead, space-time can be extended to a branch preceding the classical singularity independently of the matter coupled to the model. For large volume the correct semiclassical behavior is obtained."

====================

Marcus, where in the above paper big bounce is described? The above paper does not talk about bounce at all. The above paper only found that for kinematical states singularity is avoided. It does not imply that there is a physical resolution of singularity.

I see that a lot of credit is given to this paper of Bojowald which is in fact incorrect. It was later shown by various authors that this paper actually makes little sense because when one find physics then it does not agree with GR in the limit of small spacetime curvature and gives Planck scale corrections at density of water! This is not physics, this is plainly wrong. The mathematics which you say was "refurbished" after Ashtekar, Bojowald, Lewandowski paper was a major step in LQC which led to the bounce idea. It gave correct limit at low curvatures and a well defined scale at high curvatures. The papers before Ashtkar, Pawlowski, Singh's can be simply described in LQC as very incomplete. It is not without reason that the bounce idea in scientific community is given to Ashtekar, Pawlowski and Singh. Singh describes it in youtube video 3 in first 5 minutes which you skipped.

I don't see a reason why you say Bojowald gave bounce idea where as the first paper to show quantum bounce was not his. It was by Ashtekar, Pawlowski and Singh's PRL. I am well aware of these papers and the their details as I did my under-grad project in this. Have you read these papers? I request you to do not misinform people.

 

[physics_931]

This is the paper which showed bounce for first time. Read the abstract, the paper and compare with previous papers to know the truth. The long standing issues refer to very severe problems with works prior to this paper (that includes Bojowald's papers).


Quantum Nature of the Big Bang (arXiv:gr-qc/0602086)

Abhay Ashtekar, Tomasz Pawlowski, Parampreet Singh
(Submitted on 22 Feb 2006 (v1), last revised 6 Apr 2006 (this version, v2))

Some long standing issues concerning the quantum nature of the big bang are resolved in the context of homogeneous isotropic models with a scalar field. Specifically, the known results on the resolution of the big bang singularity in loop quantum cosmology are significantly extended as follows: i) the scalar field is shown to serve as an internal clock, thereby providing a detailed realization of the `emergent time' idea; ii) the physical Hilbert space, Dirac observables and semi-classical states are constructed rigorously; iii) the Hamiltonian constraint is solved numerically to show that the big bang is replaced by a big bounce. Thanks to the non-perturbative, background independent methods, unlike in other approaches the quantum evolution is deterministic across the deep Planck regime.

 

[2rashmi1993]

looks like am talking to future comologists.....thanx all 4 such great sources...
definitely will try them......

 

[thumbsup1]

I believe the universe is the result of a collision that occurred between two other universes, I say this as if the universe is the result of a big bounce within a much older universe then surely our universe would be in it's lowest energy state (of which it isn't).

 

[Parbat]

Unfortunately, the videos are .. "Not available in your area"

But the following front page comments are interesting;

Neil Turok who runs the Perimeter Institute for Fundamental Physics research in Canada, is so disillusioned with cosmology’s Big Bang, that he’s developed m-theory which holds that there was no bang at all - ‘simply’ the collision of three dimensional universes like ours arranged on parallel membranes. The collision takes place in a fourth dimension that we’re not aware of, but spells the end of the current universes and the beginning of a new one. But no bang.

Sir Roger Penrose has changed his mind about the Big Bang. He now imagines an eternal cycle of expanding universes where matter becomes energy and back again in the birth of new universes and so on and so on.

Has Neil Turok told somethin about how the "universes" which collide to form new universe exists?
isn't he missin somethin again?

 

[robsharp14]

i have heard something like this before, like our dimension was formed becouse of a collision of some other dimension and now we can interact with matter becouse matter was composed of one of those dimensions we have time becouse time was composed of another dimension so on and so forth. anyway remember that before we can prove any of this we have to unverstand the universe on a small scale.

 

[robsharp14]

as of the big bang,The Big Bang happened at precisely 9:14:33.397584326986723 a.m. on the morning of Thursday, April 17th, 15,108,563,209 BC. As for where it happened? It happened in a little corner of the universe that is presently occupied by a microscopic particle of pepperoni in the space within the top half of the letter "e" on the raised lettering of the word "stream" on the tip of the spray nozzle of a bottle of Windex on the third shelf of a closet in the women's bathroom of Sal & Tony's Pizzeria at the corner of 79th St. and Flatbush Avenue in Brooklyn, New York, USA, the Earth, Sol Solar System, 3rd spiral arm, Milky Way Galaxy, M31 Local Group.

 

[robsharp14]

as of the big bang,The Big Bang happened at precisely 9:14:33.397584326986723 a.m. on the morning of Thursday, April 17th, 15,108,563,209 BC. As for where it happened? It happened in a little corner of the universe that is presently occupied by a microscopic particle of pepperoni in the space within the top half of the letter "e" on the raised lettering of the word "stream" on the tip of the spray nozzle of a bottle of Windex on the third shelf of a closet in the women's bathroom of Sal & Tony's Pizzeria at the corner of 79th St. and Flatbush Avenue in Brooklyn, New York, USA, the Earth, Sol Solar System, 3rd spiral arm, Milky Way Galaxy, M31 Local Group.

until i can find hard evidence proving this wrong this is right

 

[Tanelorn]

Hey This is even more speculative than my thread! :)

 

[Gaius Baltar]

until i can find hard evidence proving this wrong this is right

Quite amusing.

unfortunately, the Nozzle I believe was invented in 1945 - and those streets & pizza places did not exist.

Neither was any of this:

the Earth, Sol Solar System, 3rd spiral arm, Milky Way Galaxy, M31 Local Group.

 

[mortalitas]

If the Big Bang created time and space, than how could the Big Bang even exist? There would be no space or time for it to be there! Its like creating water without hydrogen or oxygen.

 

[robsharp14]

unless matter traveld from the fourth dimension and that matter converts into mass and so on and so on but i doubt that this happened

 

[robsharp14]

presently occupied

 

[robsharp14]

@ gaius baltar

 

[sprudence]

Hi, I'm new on these forums, I'm not particularly geared up with mathematical prowess and only know the basics of physics, neutrinons, protons, photons, atomic structures etc, however I am absolutely fascinated by the questions that arise from potential theories.

I am a firm believer that much of what transcends on Earth are signals of understanding space or our universe.

In both Earth and Universe I feel you can look at similar occurrences, for example the explosion of a bomb must have enough potential energy. So would you say potential energy is the secret to a big bang, potential energy within space, looking for a spark... that may be a question but raises more fundamental questions such as what caused the spark, which is the main question here I think.

On the other hand as mentioned earlier in the thread, the potential collision of two universes within a multiverse may have spawned our universe - very interesting because isn't something we see with life? Bacteria can reproduce in a seemingly similar way?

My opinion, although I am certainly of no authority on the subject is that the building blocks of the universe may be more engrained in Earth that we think.. and I think ultimately that's what allows us to question and theorize these concepts.

Anyway apologies if I made no sense whatsoever.

 

[marcus]

... wasnt the big bounce Martin Bojowald's idea?...

Sure! When his mathematical model first showed a bounce, he didn't immediately CALL it by that name. But by FEBRUARY 2002 he was calling it a bounce.

See page 14 of his February 2002 paper:
==quote Bojowald's http://arxiv.org/abs/gr-qc/0202077 ==
Intuitively, we have the following picture of an evolving universe: For negative times n
of large absolute value we start from a classical universe with large volume. It contracts
... to reach a degenerate state ..., classically seen as a singularity, in which it bounces off in order to enter an expanding branch and to reach again a classical regime with large volume. ... What remains to show is that for large volume we have in fact the correct semiclassical behavior, to which we turn now...
==endquote==

In 2003 Bojowald co-authored an improved version of his model with Ashtekar and Lewandowski.

This is the paper which showed bounce for first time...
Quantum Nature of the Big Bang (arXiv:gr-qc/0602086)
Abhay Ashtekar, Tomasz Pawlowski, Parampreet Singh
(Submitted on 22 Feb 2006...)

That was an incremental improvement. How do we now IT will not be improved on in turn? Indeed the 2006 version has now been improved on by Rovelli and others and will probably be replaced. The story can hardly be considered finished when no version has yet been empirically tested. Just because Bojowald's original has been successively improved does not mean that any particular one of those improvements should be called "first".

The Loop Quantum Cosmology model Bojowald gave us around 2001 has been gradually modified over the years, not only by Bojowald himself but notably by Ashtekar, and by Singh and several others who worked with Ashtekar on this. I followed this with much interest back in 2006, reading the "new dynamics" papers of Ashtekar et al as soon as they were posted on the Arxiv.

But the fact that it has been improved and become a collective effort (as early as 2003 but especially after 2005) is no reason to deny that Bojowald's model resolved the BB singularity and gave a bounce, which by early 2002 he was calling a bounce.

No. Bojowald did not gave bounce idea. It was work of Ashtekar, Pawlowski and Singh in the paper in Physical Review Letters in 2006. After that paper came out, Bojowald tried to get bounce ...

Often in science the first time somebody does something there can be flaws and bugs need to be ironed out. Bojowald did creative pioneering work, essentially fathered Loop cosmology in which bang singularity was replaced by bounce. It would be patently disingenuous to deny this. And much credit also goes to other people (including Parampreet Singh) for later improvements.

I have no interest in squabbling about this.

 

[familia]

I think time existed before the big bang by itself or at least something like it

 

[marcus]

I think time existed before the big bang by itself or at least something like it

I could subscribe to that view

During the past ten years (at least) a number of models have been presented where space, time, and matter go back before where we used to think the singularity (a breakdown) occurred.

So far there is no scientific reason to believe one version rather than the other. No reason to suppose that the one that breaks down says "time stops" is any better than the one that doesn't suffer a breakdown and says "time continues on back".

It a case where one has to put up with the frustration and discomfort of suspending judgment and maintaining an open mind.

 

[skydivephil]

Just to echo what you said about the big bounce. Alan Guth's orioginal verison of inflation didnt work either and I believe he said so at the time. It was "fixed" by Linde and Stendhart but people still give Guth the credit and perhaps rightly so. even though there were precursors there too.

 

[K^2]

Asking a physicist what happened before the big bang is like asking what's north of the North Pole.

This is by far the best analogy I've ever seen, even if actual topology is likely to be a bit different.

 

[familia]

I think that the concept that we have of spacetime is true for our little spacetime bubble
but once we look at what is outside spacetime we will find that not all but most of the accepted laws of physics brake down except maybe time by itself

 

[skydivephil]

This is by far the best analogy I've ever seen, even if actual topology is likely to be a bit different.

Not at all. We have a lot better evidence the there's a north pole and ntohing north of it than we do there's nothing before the big bang. The latter statement is just an assumption.

 

[familia]

do we have any evidence o the universe spinning as whole relative to its event horizon

 

[Driftwood1]

can you disentangle time from space?

is nothingness something?

If the Universe expands forever and its average temperature approaches zero Kelvin, then nothing is happening - does time cease at that point?

Time needs to be defined clearly - and so does space (and infinity for that matter)

 

[skydivephil]

I believe that's what Roger Penroser Conformal Cyclic Model is about. As all matter becomes decays away there's no way to make a clock and hence no way to measure distance so the begning of the universe and thhe end are effectivley the same thing. But to be honest his new book "Cycles of TIme" is very hard to follow and I admit I was unable to do so.

 

[Driftwood1]

I believe that's what Roger Penroser Conformal Cyclic Model is about. As all matter becomes decays away there's no way to make a clock and hence no way to measure distance so the begning of the universe and thhe end are effectivley the same thing. But to be honest his new book "Cycles of TIme" is very hard to follow and I admit I was unable to do so.

Penrose is an astonishing writer - but he has no sympathy for the reader.

He published a giant telephone size book a few years ago - "Road to reality" (or something like that).

Your comment goes right to the heart of the problem - just because matter is indisguishable in an ever expanding cold universe, and there are practical problems with constructing a clock doesn't mean that the concept of time vanishes.

Mathematicians have never really bothered with reality - they are only interested in PROOF and logic - whether their theorems reflect reality is irrelevant.

thats why Pire Maths is more of a Philosophy rather than a Science

 

[Godswitch]

If the Big Bang did take place

Due to the infinite size of the universe there is a large number of possibilities, but

Before the Big Bang suggests there was some disturbance or instability in a non specified space. This was either instigated by a divine creator or is an instabilty that is inherent to large amounts of matter, the latter being more likely...!?

How everything got there is a complete unknown, what you can say though is the big bang is a convenient way of explaining what we see around us and what we can derive from facts, figures and calculations based on our observable universe seems to go hand in hand with the BBF [BIG BANG THEORY]

And what that tells us in a larger scale is...nothing, it does not tell us that the universe is infinite,only very big, it tells us that we cannot comprehend our immediate universe and that the science we have created around this, whilst very clever may only serve our purposes and not the universe we imagine is out there.

And the answer to that is - There is most definitely something responsible for the Universe!

 

[Driftwood1]

Hawking and co., considered time on an imaginary number scale, and described the big bang moment as a surface which avoids some of the problems assciated with a singularity.

Some models have more supporting evidence than others

 

[familia]

From what I understand and please feel free to correct me if I understood it wrong if the universe did start from a singularity basically the singularity would collapse under its own gravity until the point where matter can no longer be compressed now starting here and going back to before the big bang I think that the following happened and please this is just speculation on my part so please feel free to tell me I'm wrong : I think that there was a previous universe and that universe collapsed into the singularity now the reason that I think that is simple I believe that outside our universe is something that exerts pressure from every angle into the universe and that this force is responsible for the spin of the universe because objects don't spin by themselves and ultimately when our universe expands out where the gravity doesn't create any resistance to that force it will start pushing all matter back into a singularity again