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My Conversation With Alexander Vilenkin

Rational_Thinker9119
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11/11/2013 5:25:32 PM
Posted: 3 years ago
I was always very intrigued with Alexander Vilenkin's model of cosmic origins explaining the beginning of the universe naturally (which he defends extensively to this day). I had one problem with it that I couldn't keep getting out of my mind though. The WMAP data shows that the universe is flat, and recent discoveries of Dark Energy let us know that the universe will keep on expanding forever. However, Alexander Vilenkin's quantum tunnelling model predicts that the universe is closed, not flat (and it is commonly stated by scientists that a closed universe collapses, and doesn't expand forever). This seems to suggest that observable data contradicts Alexander Vilenkin's tunnelling model. For these reasons, I e-mailed Alexander Vilenkin. To my surprise, he responded to me personally:

Your quantum tunnelling model predicts a closed universe (a closed universe collapses). However, observations show that the universe is flat, and will most likely keep on expanding forever. Does this falsify your quantum tunnelling model of origins? Thank you. - Me

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"Observations show that the curvature radius of the universe is much bigger than our observable region. The universe may appear to be flat -- just like the Earth appears to be flat (since we can only see a small part of it). So a closed (but very large) universe is consistent with the data.

A closed universe necessarily collapses if it is filled with ordinary matter. But our universe is dominated by dark energy, which produces a repulsive gravitational forces and causes the universe to expand forever.

Alex V."


---

This is tremendously satisfying to me because the only problem that I saw with Vilenkin's tunnelling model is that is predicted a closed universe (which many believe entails that it will collapse). Vilenkin's answer to my question is more than sufficient, and his model has been solidified in my eyes as more than plausible.

The reason I posted this in the philosophy section is because the origin of the universe (which is what Vilenkin's tunnelling model pertains to) is a philosophical issue, even if it can be viewed as a scientific one as well.
themohawkninja
Posts: 816
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11/11/2013 5:31:52 PM
Posted: 3 years ago
Pardon me if this sounds quite stupid, but isn't the only reason why the WMAP data shows a "flat" universe, is because it's easier to look at the data two-dimensionally, just like how you use flat maps of Earth rather than a globe to find out how to get from one point on the Earth to another?
"Morals are simply a limit to man's potential."~Myself

Political correctness is like saying you can't have a steak, because a baby can't eat one ~Unknown
Rational_Thinker9119
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11/11/2013 5:37:34 PM
Posted: 3 years ago
At 11/11/2013 5:31:52 PM, themohawkninja wrote:
Pardon me if this sounds quite stupid, but isn't the only reason why the WMAP data shows a "flat" universe, is because it's easier to look at the data two-dimensionally, just like how you use flat maps of Earth rather than a globe to find out how to get from one point on the Earth to another?

Not quite. If the universe is flat, it is 3D flat. That is, of course, hard to comprehend (but it is mathematically consistent).
themohawkninja
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11/11/2013 5:39:00 PM
Posted: 3 years ago
At 11/11/2013 5:37:34 PM, Rational_Thinker9119 wrote:
At 11/11/2013 5:31:52 PM, themohawkninja wrote:
Pardon me if this sounds quite stupid, but isn't the only reason why the WMAP data shows a "flat" universe, is because it's easier to look at the data two-dimensionally, just like how you use flat maps of Earth rather than a globe to find out how to get from one point on the Earth to another?

Not quite. If the universe is flat, it is 3D flat. That is, of course, hard to comprehend (but it is mathematically consistent).

Kinda like a topographical map?
"Morals are simply a limit to man's potential."~Myself

Political correctness is like saying you can't have a steak, because a baby can't eat one ~Unknown
Poetaster
Posts: 587
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11/11/2013 6:08:40 PM
Posted: 3 years ago
At 11/11/2013 5:39:00 PM, themohawkninja wrote:
At 11/11/2013 5:37:34 PM, Rational_Thinker9119 wrote:
At 11/11/2013 5:31:52 PM, themohawkninja wrote:
Pardon me if this sounds quite stupid, but isn't the only reason why the WMAP data shows a "flat" universe, is because it's easier to look at the data two-dimensionally, just like how you use flat maps of Earth rather than a globe to find out how to get from one point on the Earth to another?

Not quite. If the universe is flat, it is 3D flat. That is, of course, hard to comprehend (but it is mathematically consistent).

Kinda like a topographical map?

Not really; we're talking about higher dimensions than 2. The curvature under consideration is not a "bending" in any direction to which we can spatially point; it is the intrinsic, so-called "Gaussian" curvature which we are measuring from the inside of the manifold itself. The manifold is, basically, the universe.
"The book you are looking for hasn't been written yet. What you are looking for you are going to have to find yourself, it's not going to be in a book..." -Sidewalker
themohawkninja
Posts: 816
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11/11/2013 6:19:55 PM
Posted: 3 years ago
At 11/11/2013 6:08:40 PM, Poetaster wrote:
At 11/11/2013 5:39:00 PM, themohawkninja wrote:
At 11/11/2013 5:37:34 PM, Rational_Thinker9119 wrote:
At 11/11/2013 5:31:52 PM, themohawkninja wrote:
Pardon me if this sounds quite stupid, but isn't the only reason why the WMAP data shows a "flat" universe, is because it's easier to look at the data two-dimensionally, just like how you use flat maps of Earth rather than a globe to find out how to get from one point on the Earth to another?

Not quite. If the universe is flat, it is 3D flat. That is, of course, hard to comprehend (but it is mathematically consistent).

Kinda like a topographical map?

Not really; we're talking about higher dimensions than 2. The curvature under consideration is not a "bending" in any direction to which we can spatially point; it is the intrinsic, so-called "Gaussian" curvature which we are measuring from the inside of the manifold itself. The manifold is, basically, the universe.

Oh jeez, I just looked it up on Wikipedia. I think I will concede with ignorance until I learn it in college in the next few years of my life.
"Morals are simply a limit to man's potential."~Myself

Political correctness is like saying you can't have a steak, because a baby can't eat one ~Unknown
1Devilsadvocate
Posts: 1,518
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11/12/2013 1:16:44 AM
Posted: 3 years ago
I think it's pretty cool that he responded. I've been thinking of asking him about the whole back and forth between WLC & LK regarding him, but I didn't think he'd respond.
I cannot write in English, because of the treacherous spelling. When I am reading, I only hear it and am unable to remember what the written word looks like."
"Albert Einstein

http://www.twainquotes.com... , http://thewritecorner.wordpress.com... , http://www.onlinecollegecourses.com...
Rational_Thinker9119
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11/12/2013 9:46:20 AM
Posted: 3 years ago
At 11/12/2013 1:16:44 AM, 1Devilsadvocate wrote:
I think it's pretty cool that he responded. I've been thinking of asking him about the whole back and forth between WLC & LK regarding him, but I didn't think he'd respond.

In my opinion, they both put their own spin on Vilenkin. Laurence thinks the BVG Theorem is weaker than it is, and Craig believes it is stronger than it is. I just take Vilenkin's words and draw my own conclusions without the added commentary of Krauss or Craig.

Also, I think he responded to my question because I poked at one of his models. I think he felt the need to defend it, and show why my assumptions were incorrect.
1Devilsadvocate
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11/12/2013 12:17:00 PM
Posted: 3 years ago
At 11/12/2013 9:46:20 AM, Rational_Thinker9119 wrote:
At 11/12/2013 1:16:44 AM, 1Devilsadvocate wrote:
I think it's pretty cool that he responded. I've been thinking of asking him about the whole back and forth between WLC & LK regarding him, but I didn't think he'd respond.

In my opinion, they both put their own spin on Vilenkin. Laurence thinks the BVG Theorem is weaker than it is, and Craig believes it is stronger than it is. I just take Vilenkin's words and draw my own conclusions without the added commentary of Krauss or Craig.

Also, I think he responded to my question because I poked at one of his models. I think he felt the need to defend it, and show why my assumptions were incorrect.

I was referring to WLC's claims that based on personal email contact Alex vilenkin
1) LK distorted / edited out important parts of the AV to LK email (I.E. not just technical details as krauss claimed.)
2) AV wrote "I think you represented what I wrote about the BGV theorem in my papers and to you personally very accurately."
http://www.reasonablefaith.org...
Whoever is lying here is clearly doing it knowingly and deceptively.
I cannot write in English, because of the treacherous spelling. When I am reading, I only hear it and am unable to remember what the written word looks like."
"Albert Einstein

http://www.twainquotes.com... , http://thewritecorner.wordpress.com... , http://www.onlinecollegecourses.com...
Rational_Thinker9119
Posts: 9,054
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11/12/2013 12:50:37 PM
Posted: 3 years ago
At 11/12/2013 12:17:00 PM, 1Devilsadvocate wrote:
At 11/12/2013 9:46:20 AM, Rational_Thinker9119 wrote:
At 11/12/2013 1:16:44 AM, 1Devilsadvocate wrote:
I think it's pretty cool that he responded. I've been thinking of asking him about the whole back and forth between WLC & LK regarding him, but I didn't think he'd respond.

In my opinion, they both put their own spin on Vilenkin. Laurence thinks the BVG Theorem is weaker than it is, and Craig believes it is stronger than it is. I just take Vilenkin's words and draw my own conclusions without the added commentary of Krauss or Craig.

Also, I think he responded to my question because I poked at one of his models. I think he felt the need to defend it, and show why my assumptions were incorrect.

I was referring to WLC's claims that based on personal email contact Alex vilenkin

I know, it was about the BVG Theorem.

1) LK distorted / edited out important parts of the AV to LK email (I.E. not just technical details as krauss claimed.)
2) AV wrote "I think you represented what I wrote about the BGV theorem in my papers and to you personally very accurately."
http://www.reasonablefaith.org...
Whoever is lying here is clearly doing it knowingly and deceptively.

Vilenkin was just being polite to Craig. In the past, Vilenkin has made it known that Craig has misrepresented some things. For example, Craig says the BVG Theorem shows an absolute beginning. Vilenkin said in a conversation with Victor Stenger:

"[T]he words 'absolute beginning' do raise some red flags." - Alexander Vilenkin [Victor J. [Stenger, The Fallacy of Fine-Tuning, 2011.]

So, Craig says the theory proved a beginning of the universe, but Alexander Vilenkin says that is not true:

"Does your theorem prove the universe must have had a beginning?" - Victor Stenger

"No. But it proves that the expansion of the universe must have had a beginning." - Alexander Vilenkin [Stenger, The Fallacy of Fine-Tuning, 2011]

Either way, Vilenkin said himself that there are models where his theorem may not hold. Here is a full quote from Vilenkin in the E-mail:

"Jaume Garriga and I are now exploring a picture of the multiverse where the BGV theorem may not apply. In bubbles of negative vacuum energy, expansion is followed by contraction, and it is usually assumed that this ends in a big crunch singularity. However, it is conceivable (and many people think likely) that singularities will be resolved in the theory of quantum gravity, so the internal collapse of the bubbles will be followed by an expansion. In this scenario, a typical worldline will go through a succession of expanding and contracting regions , and it is not at all clear that the BGV assumption (expansion on average) will be satisfied." " Alexander Vilenkin

Even if we assume the universe did have a beginning, his quantum tunnelling model explains it just fine without need for God. So, I don't know why Craig is so hell bent on showing a beginning. That wouldn't mean God exists:

"As a result of the tunnelling event, a finite-sized universe, filled with a false vacuum, pops out of nowhere ("nucleates") and immediately starts to inflate...What could have caused the tunnelling? Remarkably, the answer is that no cause is required." - Professor of Physics, Alexander Vilenkin [Alexander Vilenkin: Many worlds in one: The search for other universes (P. 181)]