Eternal Inflation: Check Understanding & Ask Qs

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In summary, those of you familiar with this theory tell me if I'm getting it right. As the universe expands, all bodies that are not bound together move apart while those that are eventually fall together into black holes. As the universe cools, the black holes evaporate by Hawking radiation. Eventually, there are vast regions of space that is so empty that literally nothing exists within a cosmic event horizon. Under these conditions, random quantum fluctuations can create miniature black holes, which quickly evaporate. However, these black holes are different from normal black holes in that they form from the inside out, no pre-existing matter falls together to form them. Due to the way they are formed, an observer inside the event horizon of the black hole
  • #1
mrspeedybob
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I just read this...

http://arxiv.org/abs/gr-qc/0505037

Here's my condensed paraphrase, Those of you familiar with this theory tell me if I'm getting it right.

As the universe expands All bodies which are not bound together move apart while those that are eventually fall together into black holes. As the universe cools the black holes evaporate by Hawking radiation. Eventually there are vast regions of space that is so empty that literally nothing exists within a cosmic event horizon. Under these conditions random quantum fluctuations can create miniature black holes, which quickly evaporate. However these black holes are different from normal black holes in that they form from the inside out, no pre-existing matter falls together to form them. Due to the way they are formed an observer inside the event horizon of the black hole would see it's formation as a "big bang" event that would be the beginning of infinite time and space. Our universe likely began this way and will likely spawn an indefinite number of other universes this way. A "parent" universe likely spawned ours this way and was likely spawned that way itself.

, OK. Did I get that all right? If not , what did I misunderstand? Is this a mainstream theory or a fringe theory. And, what is it about absolutely empty space that makes the conditions right for the random and spontaneous formation of these black holes / daughter universes.
 
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  • #2


Someone else will have to respond to the bulk of your questions, Bob. I can just address a small sliver, but maybe that will help.

What you are talking about is not what is usually meant by "eternal inflation". The authority on that is Andrei Linde (at Stanford). Linde has a lot of papers, and they get a lot of citations. There are probably several people here who would like to explain Eternal Infl. a la Linde to you.

What you have is a link to a 2005 paper by Sean Carroll and Jennifer Chen. Since that time it got only 15 citations,
http://arxiv.org/cits/gr-qc/0505037
and none of those other scholars picked up the idea and ran with it. They all have their different ideas and are just mentioning Carroll's idea, mostly just in passing.

Also Sean Carroll himself did not follow up. He is a charming witty affable guy that everybody likes who was on tenure track at Chicago U and did not get tenure and so took a Res. Assoc. position at Caltech. He is something of a media personality too I think.
Gifted with language. Multifaceted. Could write books like Brian Greene or have a regular TV show like Michio Kaku. Well connected.

But I don't think the idea caught on. I think everybody said "Oh! what an interesting idea!" and dropped it.

I could be wrong. I haven't been paying attention to Carroll's papers. But it has been over 5 years since 2005 and I haven't seen much happening with that idea.

The real Andrei Linde "Eternal Inflation" has gotten a lot more attention over the years.
Try looking up Linde's papers. And look at all the people that have cited them.
You need to learn to use arxiv.org if you don't already.
Here are Linde's 126 papers on arxiv:
http://arxiv.org/find/grp_physics/1/au:+Linde_A/0/1/0/all/0/1

Here is a 2007 Linde paper, as a sample
http://arxiv.org/abs/0705.0164
When you have a paper, to find the cites, replace "abs" by "cits"
http://arxiv.org/cits/0705.0164
You will see it got more than 100 cites by other scholars and in less time (since May 2007 compared with Carroll's 15 since May 2005).

I don't follow Linde papers either. But I can't help knowing his influence and stature.
More central, more heavyweight, more highly regarded by the inflation cosmology crowd.

I hope you find someone here to discuss the Carroll-Chen paper with!
=======================
To let you know where I'm coming from:
My main interest in this general area is the field called "quantum cosmology"---the research papers you get when you do a spires search with "quantum cosmology" as keyword, and ranked by citation count. That is where the main effort is to understand what happened around the start of expansion and what model should replace the "singularity".

Here are 400+ QC papers that have appeared in the years starting with 2007
http://www.slac.stanford.edu/spires/find/hep/www?rawcmd=dk+quantum+cosmology+and+date%3E2006&FORMAT=WWW&SEQUENCE=citecount%28d%29

I like the most highly cited QC research model because it has been judged TESTABLE by the theory testing professionals---falsifiable by cosmic microwave background data that could be collected by an affordable spacecraft . I like the testability falsifiability angle.
A testing professional who is into early universe models is Aurelien Barrau.

But people's interests differ. Some people are interested in multiverses and in immense inflation scenarios. I'm more interested in what we might be able to tell about the one big bang we know happened.

Here's a sample Barrau http://arXiv.org/abs/0902.0145
It was published in 2009 and already has been cited in 32 other papers:
http://arXiv.org/cits/0902.0145
it deals with possible "footprints" of bounce cosmology.
cites don't tell the whole story but they help. You can see that the citing papers did not just mention and let drop. many of them carried the ideas forward.
Cites give an idea of how other research professionals view stuff.

So I keep aware of that as well as using my own independent judgment.

If anyone is curious and wants to see some papers by Barrau and friends, just say. I will get some links.
 
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  • #3


I think this paper by Guth may be of help:
http://arxiv.org/abs/hep-th/0702178
My understanding of eternal inflaton is that there is material in the early universe called a false vacuum which has replusive gravity. This material is exponentially expanding but it also decays into our familair true vacuum. When it does this it dumps its energy into matter and radiation creating our "pocket universe". However assuming the false vacuum expands fatser than it decays the process must repeat, hence inflation is eternal, creating an endless number of pocket universes Thats my understanding, but I am no cosmologist, so if anyone wants to correct me please do so.
 
  • #4


@skydive,
right on target! Much more representative by what is usually meant by "eternal inflation" than that one-of-a-kind 2005 paper by Carroll and Chen.
 
  • #5


I would say that your condensed paraphrase is mostly correct. However, there are a few points that could use some clarification.

Firstly, the concept of eternal inflation is a part of the broader theory of cosmic inflation, which proposes that the universe underwent a period of rapid expansion in its early stages. Eternal inflation suggests that this rapid expansion is ongoing and will continue forever, resulting in the creation of an infinite number of universes.

Secondly, while the formation of black holes is a part of this theory, it is not the only mechanism by which new universes are created. Other proposed mechanisms include the collapse of cosmic bubbles and the collision of universes.

Thirdly, the idea of "infinite time and space" can be a bit misleading in this context. While the number of universes may be infinite, the amount of time that has passed since the beginning of this eternal inflation process is still finite. It is also important to note that the concept of time may be different in these other universes, making it difficult to truly understand the concept of "infinite time."

In terms of its status in the scientific community, the theory of eternal inflation is still a topic of ongoing research and debate. While it has gained some support from observational evidence, there are still many unanswered questions and alternative theories.

As for the conditions that allow for the spontaneous formation of black holes and daughter universes, it is believed that the extreme emptiness and low energy state of the universe during inflation provide the perfect environment for quantum fluctuations to occur and give rise to these structures. However, this is an area of active research and there is still much to be understood about the underlying mechanisms.

Overall, your understanding of the concept of eternal inflation is mostly correct, but it is a complex and ongoing area of research that continues to be explored by scientists.
 

Related to Eternal Inflation: Check Understanding & Ask Qs

1. What is eternal inflation?

Eternal inflation is a theory in cosmology that suggests that the universe is expanding at an accelerating rate and will continue to do so forever. It proposes that new universes are constantly being created within a larger multiverse, making the universe infinitely large and constantly expanding.

2. How does eternal inflation differ from the Big Bang theory?

The Big Bang theory suggests that the universe began with a singularity and has been expanding ever since. Eternal inflation, on the other hand, proposes that the universe is constantly expanding and new universes are being created within a larger multiverse.

3. Is there evidence for eternal inflation?

While there is no direct evidence for eternal inflation, it is a widely accepted theory in cosmology and is supported by the observations of the cosmic microwave background radiation and the accelerating expansion of the universe.

4. How does eternal inflation affect the concept of a beginning of the universe?

Eternal inflation proposes that the universe has no beginning and will continue to expand forever. This challenges the traditional idea of a beginning of the universe, as it suggests that the universe has always existed in some form.

5. Are there any potential implications or consequences of eternal inflation?

If eternal inflation is true, it would mean that our universe is just one of an infinite number of universes within a larger multiverse. This could have implications for our understanding of the laws of physics and the possibility of other life forms in other universes.

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