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Author Topic:   Re-Problems With The Big Bang Theory
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 7 of 273 (470919)
06-13-2008 12:24 PM
Reply to: Message 6 by ICANT
06-13-2008 11:24 AM


Re: Re-The Flatness Problem
The problem is a simple big bang theory cannot explain how an Omega so close to critical density could arise
True - and is explained extremely well by inflation. Evidence in support of inflation is growing all the time, especially from WMAP.
Edited by Admin, : Fix quote.

This message is a reply to:
 Message 6 by ICANT, posted 06-13-2008 11:24 AM ICANT has replied

Replies to this message:
 Message 10 by ICANT, posted 06-13-2008 1:37 PM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 21 of 273 (471125)
06-14-2008 5:24 PM
Reply to: Message 20 by Agobot
06-14-2008 4:09 PM


Re: Multiple Big Bangs
we could easily conclude that if 1 Big Bang was ever possible, then multiple Big Bangs are likely to have taken place in the seemingly endless space.
It's not as simple as this - the Universe is *highly* non-linear. You cannot naively extrapolate from any one situation. You can certainly suggest it, investigate it, model it, and test it. But you cannot say "are likely to have taken place" from simple musing.
In this case, you have to realise that the Big Bang is not something that occurs *in* space. It is the entirety of space. And so your extraplolation is invalid at the first step.
HOWEVER, we do have several models where the Big Bang and "space" are actually only a subpart of a greater (possibly higher dimensional) space, and your idea here is certainly seriously considered (suggested, investigated, modelled, tested), as well as its impact on the fact of our existence.
Just to add - our Universe is probably plenty big enough to come up with life bearing planets. The multiverse (multiple big bangs) helps to come up with a universe simply capable of supporting stars and planets of any form, out of the infinitude of possible universes that wouldn't even support structure (atoms), never mind stars!
Edited by cavediver, : No reason given.

This message is a reply to:
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cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 22 of 273 (471129)
06-14-2008 5:38 PM
Reply to: Message 10 by ICANT
06-13-2008 1:37 PM


Re: Re-The Flatness Problem
Which hypothesis of Inflation are you refering to.
Any of them.
I don't want to fall into the trap of me talking about one version and you about a totaly different version.
Don't worry, I'm more than capable of explaining all of them. However, I cannot vouch that you will understand them.

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cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 23 of 273 (471133)
06-14-2008 5:59 PM
Reply to: Message 16 by ICANT
06-14-2008 1:08 AM


Re: Update Your Model
I like these assumptions without explanation.
Do you? Do you also like omitting the very next sentence from the passage you quoted which shows how these assumptions are made unnecessary with inflation? I would have thought a pastor would have been above common trolling but perhaps I am wrong...

This message is a reply to:
 Message 16 by ICANT, posted 06-14-2008 1:08 AM ICANT has replied

Replies to this message:
 Message 25 by IamJoseph, posted 06-15-2008 5:27 AM cavediver has replied
 Message 35 by ICANT, posted 06-15-2008 2:31 PM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 26 of 273 (471153)
06-15-2008 6:24 AM
Reply to: Message 25 by IamJoseph
06-15-2008 5:27 AM


Re: Update Your Model
I am confounded how factors such as inflation can occur of its own, w/o an external triggering factor.
You are confounded because you have merely been told of the existence of a concept known as inflation. Other than the most fundemental basics, its nature has not been discussed here - what it is, why it occurs, details of the possible mechanisms behind it, its naturalness (or unnaturalness) in the context of quantum field theory, cosmology and quantum gravity.

This message is a reply to:
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cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 29 of 273 (471159)
06-15-2008 7:03 AM
Reply to: Message 28 by Agobot
06-15-2008 6:57 AM


Where is the evidence for this claim that there is no space beyond our universe?
What do you mean by "space"? Surely any space "beyond" the Universe is already included *in* the Universe?
Edited by cavediver, : superfluous comma

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Replies to this message:
 Message 30 by bluescat48, posted 06-15-2008 9:45 AM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 31 of 273 (471173)
06-15-2008 10:34 AM
Reply to: Message 30 by bluescat48
06-15-2008 9:45 AM


I would appear that there are 2 different connotations of the word "Space" being used in this and other threads.
Only two??? That would be so much easier...
The problem is that people with no background in the subject are expecting answers, and expecting to UNDERSTAND the answers to these questions. To explain this at even the most basic of levels requires presenting a substantial body of introductory material. The questioners then proceed to question, critique, and ridicule this most basic of background information, and the original question is never addressed.
2) Space is the entire entity of the visible & invisible (beyond the visible) universe. In this view space is universal regardless of the big bang in that it always existed, just that it contained nothing.
This is the classic untrained common-sense belief, with the impression that the Universe is expanding into this "space".
If space did not exist before the Big Bang then what occupied the volume we now call space?
This question presupposes the above erroneous view - what volume?
What occupied the volume of the Halo 3 world (or any other first person shooter) before it was written?
The problem seems to be "What is space?", "Where is space?"
and "Is space Infinite?" None of which can be answered objectively.
I disagree. But at what level do you want an answer? At the level of complete ignorance of cosmology? After having read some Brian Greene or Hawking? After your final year undergrad cosmology course? As a beginning PhD student of General Relativity/Quantum Gravity/String Theory? Or front line research? My answer requires a blackboard, considerable handwaving, a few props, and a fair bit of time. It's damn hard to convert that to typing replies on a discussion board.

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Replies to this message:
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 Message 33 by Agobot, posted 06-15-2008 12:28 PM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 34 of 273 (471194)
06-15-2008 2:30 PM
Reply to: Message 33 by Agobot
06-15-2008 12:28 PM


that's why an internet link with the supposed evidence that there is no space outside our universe, will give you much credit and we won't have to take your word for it.
I don't give a shit whether you take my word for anything. I'm not here to debate cosmology - I do that with other experts - I'm here to help interested readers understand something of the Universe.
the supposed evidence that there is no space outside our universe
You don't even understand the words you are using. I have already asked you:
cavediver writes:
What do you mean by "space"? Surely any space "beyond" the Universe is already included *in* the Universe?
but you have yet to answer...

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Replies to this message:
 Message 38 by ICANT, posted 06-15-2008 2:54 PM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 36 of 273 (471200)
06-15-2008 2:43 PM
Reply to: Message 35 by ICANT
06-15-2008 2:31 PM


Re: Update Your Model
Without inflation the BBT would be dead.
Incorrect - there would just be some explaining to do, and there are competing ideas to inflation. There is plenty of evidence for the Big Bang, and thus we do not simply discard it on the basis of open questions/problems. "We do not know yet" is not the point where you discard a theory.
I was wanting to know which one had become a theory.
Why? They differ on fundemental mechanism, not coarse-grained effect. It is the latter that we care about in terms of solving the issues with non-inflationary BBT.

This message is a reply to:
 Message 35 by ICANT, posted 06-15-2008 2:31 PM ICANT has replied

Replies to this message:
 Message 42 by ICANT, posted 06-15-2008 3:20 PM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 40 of 273 (471210)
06-15-2008 3:13 PM
Reply to: Message 39 by ICANT
06-15-2008 3:03 PM


Re: Update Your Model
Which hypothesis solves the problems listed?
Present the one you think that does and we can discuss it.
It's been done. You brought up flatness, and you were replied with inflation. So, what did you want to discuss?
There is no updated model.
Funny, I could have sworn there was Lambda CDM... but then you, the pastor, seem to know a hell of lot more than me, the cosmologist...
When the patches are just guesses.
So you are discounting the evidence for inflation? Please present your critique...
Edited by cavediver, : No reason given.

This message is a reply to:
 Message 39 by ICANT, posted 06-15-2008 3:03 PM ICANT has replied

Replies to this message:
 Message 45 by ICANT, posted 06-15-2008 4:18 PM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 41 of 273 (471212)
06-15-2008 3:18 PM
Reply to: Message 38 by ICANT
06-15-2008 2:54 PM


Re: Re-space
Unless you are backtracking
Backtracking, you condescending twat??? Yes, you're so right. You're running rings around my knowledge, having grasped everything I have ever explained to you, and know I am struggling to keep up.
Then is it just expanding into itself and we just think the universe is billions of light years across because we are actually so small?
Yep, you got it.

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 Message 38 by ICANT, posted 06-15-2008 2:54 PM ICANT has not replied

Replies to this message:
 Message 44 by Agobot, posted 06-15-2008 4:11 PM cavediver has replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 43 of 273 (471216)
06-15-2008 3:26 PM
Reply to: Message 42 by ICANT
06-15-2008 3:20 PM


Re: Update Your Model
No answer within the theory.
That is the MAIN MOTIVATION for inflationay cosmology.
Yes, well done ICANT. This has been our position for 20 years. But there are ideas other than inflation as I have just stated. Or are you refuting that?

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 Message 42 by ICANT, posted 06-15-2008 3:20 PM ICANT has replied

Replies to this message:
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cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 46 of 273 (471230)
06-15-2008 4:21 PM
Reply to: Message 44 by Agobot
06-15-2008 4:11 PM


Re: Re-space
Is the Big Bang theory going to crumble to dust if redshifts are proven to not have been caused by spatial expansion?
Yes, of course.

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cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 48 of 273 (471232)
06-15-2008 4:33 PM
Reply to: Message 45 by ICANT
06-15-2008 4:18 PM


Re: Update Your Model
So which version of Inflation as I asked you for earlier.
Who cares? Almost certainly none of them - it will be a mixture of several of the ideas, but we will not know for sure until we know the Planckian physics, which we may not know for decades. As we work out ways around the various problems with the specific models, this may allow us a route towards the actual Planckian physics. This is how we progress. But a period of inflation is simply a de-Sitter-like phase to the early Universe - an exceptionally simple concept that sweeps away many of the earlier issues with the BBT. And we see the evidence of inflation in the CMBR. Are you refuting that evidence?
Scaler field driven inflation does not eliminate the singularity.
No mechanisms of inflation eliminate the singularity, so this is hardly an issue, is it?
Then there is the cosmological constant problem.
Not an issue of the BBT. It is an issue of our understanding of Planckian physics.

This message is a reply to:
 Message 45 by ICANT, posted 06-15-2008 4:18 PM ICANT has replied

Replies to this message:
 Message 49 by Agobot, posted 06-15-2008 4:49 PM cavediver has replied
 Message 52 by ICANT, posted 06-15-2008 10:10 PM cavediver has not replied

cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 50 of 273 (471237)
06-15-2008 4:53 PM
Reply to: Message 49 by Agobot
06-15-2008 4:49 PM


Re: Update Your Model
if the universe is infinitely small now
Well, it's not...
If it's infinitely small, what makes you say the singularity exists at all?
It isn't, and I never said the singularity exists.

This message is a reply to:
 Message 49 by Agobot, posted 06-15-2008 4:49 PM Agobot has replied

Replies to this message:
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