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Various Pre Big Bang Scenarios Discussed By Pros


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#1 Flummoxed

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Posted 31 January 2019 - 06:53 AM

A lot of threads on this forum and others are discussing pre bang models, Edit based around inflationary theory, here is a simple easy to follow link on what is happening in inflationary theory, as a primer to what the link below is about http://aether.lbl.go...-beginners.html

 

The following is a discussion by Roger Penrose, Sean Carroll, Laura Mersini-Hougton 1 second after the big bang from a hot dense universe is not debated and assumed fact by all. Prior to this the pros disagree, but it is also interesting to see how much they agree.

 

 

Roger has an interesting theory on how the inflationary phase of the BB may have appeared to have happened.

 

Edit I think this theory is what Penrose was referring too > Conformal cyclic theory https://en.wikipedia...ic_cosmology.  


Edited by Flummoxed, 21 February 2019 - 04:03 PM.


#2 Flummoxed

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Posted 31 January 2019 - 01:05 PM

Penrose discussing his theory of the universe.  ignore the adds its a bit slow.


Edited by Flummoxed, 31 January 2019 - 01:10 PM.


#3 Flummoxed

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Posted 31 January 2019 - 01:20 PM

Could Penrose have lost the plot ? His idea rests on vanishing entropy of gravity I think. Entopy has been increasing since the Big Bang. Gravitationally is it decreasing ? .  I think I just lost the plot


Edited by Flummoxed, 31 January 2019 - 01:27 PM.


#4 Flummoxed

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Posted 03 February 2019 - 09:14 AM

Could Penrose have lost the plot ? His idea rests on vanishing entropy of gravity I think. Entopy has been increasing since the Big Bang. Gravitationally is it decreasing ? .  I think I just lost the plot

 

Vanishing Entropy of GRAVITY ???? Could multiple big bangs have occurred in the past. Penrose appears to think so, ie he does not accept there was nothing before a big bang 13.8 billion years ago.

 

I have had a bit of a look at Sean Carrol and his posts are generally waffle with snippets of good stuff. This is about the most concise link I could find by him.

 

 

Empty space > no matter > no gravity, results in a big bang. Currently we are headed to empty space, whereby a quantum fluctuation might again become a big bang in a googleplex years time. 

 

Perhaps both Penrose and Carrol are correct, the universe did not have a beginning. upto 13.8 billion years ago we think know. 1 second before then no one knows.


Edited by Flummoxed, 03 February 2019 - 09:15 AM.


#5 Flummoxed

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Posted 03 February 2019 - 09:50 AM

Laura Mensin-Houghton is very interesting. One of her other theories is that singularities in black holes dont form because of hawking radiation. Thats an idea worth following up. 

 

I am not sure I buy her multiverse hypothesis "She is a proponent of the multiverse hypothesis and the author of a theory for the origin of the universe that holds that our universe is one of many selected by quantum gravitational dynamics of matter and energy."

 

https://en.wikipedia...e-twsNautilus-8

 

My simple abridged conclusion is, we are the result of a lot of quantum fluctuations that occurred in empty space. 

 

The expansion of space is accelerating.

 

Space in the absence of gravitational distortion, expands at rates only experienced at the time of inflation, driven by dark energy.

 

Without gravitational distortion of space at high rates of expansion, virtual particles became mass, and it might happen again at some distant point in the future. PERHAPS 

 

How is black body radiation perceived at high speed. Does space become hot for a moving object. :) Are emptier portions of space hotter than others ? I wonder

 

Would anyone care to comment. 


Edited by Flummoxed, 03 February 2019 - 09:51 AM.


#6 Dubbelosix

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Posted 03 February 2019 - 10:10 AM

A lot of threads on this forum and others are discussing pre bang models, 

 

The following is a discussion by Roger Penrose, Sean Carroll, Laura Mersini-Hougton 1 second after the big bang from a hot dense universe is not debated and assumed fact by all. Prior to this this the pros disagree. 

 

 

Roger has an interesting theory on how the inflationary phase of the BB may have appeared to have happened.

 

Edit I think this theory is what Penrose was referring too > Conformal cyclic theory https://en.wikipedia...ic_cosmology.  

 

 

The issue here I have, is that it is clear, that for any scientist to say ''it is not debated'' is an indication of not being well-read. There have been numerous discussions on a pre-big bang phase, the problem is that a pre big bang phase could easily give what we consider today, a hot big bang. Now, it is true the hot big bang phase is not disputed, what is disputed here is that it is the ''origin of time itself.''



#7 Dubbelosix

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Posted 03 February 2019 - 10:16 AM

Since supermassive cold spots cannot be predicted with the hot big bang alone, I have convinced myself of the possibility of the cold phase being able to answer this.



#8 Flummoxed

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Posted 03 February 2019 - 11:37 AM

The issue here I have, is that it is clear, that for any scientist to say ''it is not debated'' is an indication of not being well-read. There have been numerous discussions on a pre-big bang phase, the problem is that a pre big bang phase could easily give what we consider today, a hot big bang. Now, it is true the hot big bang phase is not disputed, what is disputed here is that it is the ''origin of time itself.''

 

Sean Carrol points out that the subject of pre 1 second to big bang is complete speculation. 

 

 

Since supermassive cold spots cannot be predicted with the hot big bang alone, I have convinced myself of the possibility of the cold phase being able to answer this.

 

 

Maybe. But as a consequence of taking a walk and a couple of beers. Why do quantum fluctuations need to be cold. I do not think that is necessary although the lowest possible energy state would be at 0 kelvin in a stationary universe, but why should a particle appear at 0Kelvin if its moving in an inflationary universe.

 

Most of the ideas I tend to chase arise from the standard model of physics, although it is interesting to read the odd alternative theory. One in particular on this forum was based around the UNRUH effect, and some other slightly less plausible ideas.

 

A Universe evolving out of the UNRUH effect is not as crazy as it seems, in a inflationary universe, ie space growing at faster than light speed. (Think Hawking radiation at a black hole event horizon) virtual particles become separated and do not destroy each other. At the inflationary stage of the universe virtual particles may also become separated due to fact that the space between them is growing at faster than light speed. To a stationary observer this space might be cold. To a moving observer it would be hot.

 

Vanishing gravitational entropy via Penrose might not be such a daft idea. 

 

What drives the expansion of space, in the absence of gravity, perhaps its something to do with negative mass effects seen in condensates which are v cold and not affected by gravity. 


Edited by Flummoxed, 03 February 2019 - 11:47 AM.


#9 Dubbelosix

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Posted 03 February 2019 - 11:48 AM

Yes it is speculation.

 

But then everything leading up to a big bang, is a speculation. However, I have pointed out a few times, the big bang as a low entropy large temperature state is at odds with the third law of thermodynamics. We only restore sense by introducing a cold phase that existed before the hot phase.



#10 Flummoxed

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Posted 04 February 2019 - 03:58 AM

Yes it is speculation.

 

But then everything leading up to a big bang, is a speculation. However, I have pointed out a few times, the big bang as a low entropy large temperature state is at odds with the third law of thermodynamics. We only restore sense by introducing a cold phase that existed before the hot phase.

 

Thermal entropy or gravitational entropy. Gravitational entropy in the universe as pointed out by Penrose is headed towards zero. 

 

Accepting that modern physics is mostly correct and inflation did take place at the same time matter came into existence over a region of inflating space,

 

Can both a hot and a cold phase exist at the same time for different observers? 

 

I am going to play with Hawking radiation, the Unruh effect and Black Body radiation for a while, during the inflationary stage of the universe.

I kicked up this idea a few months back, and did not pursue it as I was being blinkered. 

 

Penroses multiple bangs separated by time in an infinite universe are growing on me. I no longer suspect he lost the plot, and think he may be more right than everyone else. He worked with Hawking and is very obviously aware of Hawking radiation around black holes. Spontaneous particle production due to Hawking radiation, might have an equivalent in an inflationary universe. What temperature would any particles spontaneously be that appeared, why should they be cold.? A stationary inflating space might appear cold to one observer but not an accelerating virtual particle.



#11 Dubbelosix

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Posted 04 February 2019 - 04:22 AM

I enjoy your enthusiasm, really. I used to think about quotations from the pro's constantly. Though, it needs to be clearly addressed, for instance, on one hand you talk about the acceptance of a hot history and you note, Penrose also talks about this strange ''low entropy'' in a high thermal state - yet he makes no mention of why this makes no sense. A thermal state can only possess a large entropy in contrary to how we are somewhat forced by academia to think about big bang.

 

I argue if you want a picture that makes sense, then big bang cannot be the beginning, but it did come from a low entropy state that pre-existed it. There is absolutely nothing wrong with this mode of thinking and was part of the reason I later came to find out, why cold big bangs where first investigated.

 

Also you keep talking about inflation, but they predict parallel universes and I do not class these in the category of theories.  They cannot be tested. However, a pre-big bang phase perhaps could be, through indirect evidence. Also, Penrose states that inflation needs to be abandoned with because it requires a fine tuning, so it creates more problems than it can fix.



#12 Dubbelosix

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Posted 04 February 2019 - 04:24 AM

As for the ground state, you can have thermal wavelengths quenched to make a condensate, but there should still be present a dense gravitational field. It is from this field, virtual particles can get a ''boost'' into real matter.



#13 Dubbelosix

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Posted 04 February 2019 - 04:24 AM

The quantization of the gravitational field, leads to the transformations capable of describing that process.



#14 Dubbelosix

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Posted 04 February 2019 - 04:28 AM

You also asked

 

''Can both a hot and a cold phase exist at the same time for different observers?''

 

 

Yes it is possible with transformation laws, the problem is that there are no human or intelligent recording device around which can like an  observer (and consciously recognize it). A pre big bang state though, is an absolute state. That is, it exists at absolute zero temperature. There will be more pieces to the puzzle I expect.



#15 Flummoxed

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Posted 04 February 2019 - 04:47 AM

You also asked

 

''Can both a hot and a cold phase exist at the same time for different observers?''

 

 

Yes it is possible with transformation laws, the problem is that there are no human or intelligent recording device around which can like an  observer (and consciously recognize it). A pre big bang state though, is an absolute state. That is, it exists at absolute zero temperature. There will be more pieces to the puzzle I expect.

 

Thanks for the vote of confidence. It might not have dawned on your genius, but I asked the question twice above in an attempt to direct you away from your none conventional line of thinking, and back towards Penroses line of thinking. Penrose being one of the Pros mentioned in the OP above. 

 

You need to grasp the concept of eternity in Penroses ideas, he is not talking multiverses.  :sherlock:


Edited by Flummoxed, 04 February 2019 - 04:48 AM.


#16 Dubbelosix

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Posted 04 February 2019 - 05:16 AM

I am sorry to burst your bubble, but even Penrose has called his model ''madness'' but so mad it could be right. I am absolutely capable of conceptualizing his model, but I am not satisfied. Neither is he really.


Edited by Dubbelosix, 04 February 2019 - 05:16 AM.


#17 Dubbelosix

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Posted 04 February 2019 - 05:17 AM

Also, this is not a matter of being misinformed, I have followed his model for longer than you discovered it the other day.