Warp wrote:
>   Has it even been hypothesized *why* the expansion of the universe
> happens? 

Dark Energy!  ;-)

Seriously, I think they think it has something to do with zero-point energy, 
i.e., the fact that virtual particles will spontaneously come into existence 
and then annihilate each other again.  I can't really say I understand it 
beyond "it's something about quantum" (as Terry Pratchett would say)

-- 
Darren New, San Diego CA, USA (PST)
   Serving Suggestion:
     "Don't serve this any more. It's awful."

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Darren New <dne### [at] sanrrcom> wrote:
> Seriously, I think they think it has something to do with zero-point energy, 
> i.e., the fact that virtual particles will spontaneously come into existence 
> and then annihilate each other again.  I can't really say I understand it 
> beyond "it's something about quantum" (as Terry Pratchett would say)

  Even if that explains the current expansions, would it explain the
initial rapid inflation?

  Seemingly not, as there appears to be a hypothesis for a different particle
that caused the cosmic inflation: http://en.wikipedia.org/wiki/Inflaton

  I don't understand, however, how a particle would explain inflation
(or just the "normal" expansion of the universe), because such a particle
should be bound to the maximum speed limit of c, as any other particle.
How can it cause the universe to expand faster than c?

-- 
                                                          - Warp

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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Seriously, I think they think it has something to do with zero-point energy, 
>> i.e., the fact that virtual particles will spontaneously come into existence 
>> and then annihilate each other again.  I can't really say I understand it 
>> beyond "it's something about quantum" (as Terry Pratchett would say)
> 
>   Even if that explains the current expansions, would it explain the
> initial rapid inflation?

I don't think so, no. Certainly not if the whole quantum mess didn't even 
start until after inflation. (I hadn't realized that "inflation" actually 
happened that early and quickly until this conversation.)

>   Seemingly not, as there appears to be a hypothesis for a different particle
> that caused the cosmic inflation: http://en.wikipedia.org/wiki/Inflaton

Damn. Inflation ended when the universe was only one meter across? Yow.

> How can it cause the universe to expand faster than c?

Only if the actual energy turned into space, or something? I have nothing 
buy BS guesses for that. :-)

-- 
Darren New, San Diego CA, USA (PST)
   Serving Suggestion:
     "Don't serve this any more. It's awful."

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Darren New <dne### [at] sanrrcom> wrote:
> >   Seemingly not, as there appears to be a hypothesis for a different particle
> > that caused the cosmic inflation: http://en.wikipedia.org/wiki/Inflaton

> Damn. Inflation ended when the universe was only one meter across? Yow.

  I'm not sure it says that. It says how long it took for the universe
to become 1 meter accross, not that the inflation ended there. (Also this
seems to completely lack a reference, so it could be some editor's BS.)

-- 
                                                          - Warp

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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>>>   Seemingly not, as there appears to be a hypothesis for a different particle
>>> that caused the cosmic inflation: http://en.wikipedia.org/wiki/Inflaton
> 
>> Damn. Inflation ended when the universe was only one meter across? Yow.
> 
>   I'm not sure it says that. It says how long it took for the universe
> to become 1 meter accross, not that the inflation ended there. (Also this
> seems to completely lack a reference, so it could be some editor's BS.)
> 

Good point.  http://en.wikipedia.org/wiki/Early_universe#Inflationary_epoch
implies it ended somewhere around 10^-32

http://en.wikipedia.org/wiki/Inflationary_epoch

And of course, they say "then the universe filled up with energy that came 
from potential energy."  I don't know how you store potential energy in a 
"field", so it's either way over my head, or BS. :-)

-- 
Darren New, San Diego CA, USA (PST)
   Serving Suggestion:
     "Don't serve this any more. It's awful."

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http://io9.com/5694701/does-cosmic-background-radiation-reveal-the-universe-before-the-big-bang

Actually, I think it's clear nobody really has a clue. :-)

-- 
Darren New, San Diego CA, USA (PST)
   Serving Suggestion:
     "Don't serve this any more. It's awful."

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Am 21.11.2010 04:12, schrieb Darren New:
>
>
http://io9.com/5694701/does-cosmic-background-radiation-reveal-the-universe-before-the-big-bang
>
>
> Actually, I think it's clear nobody really has a clue. :-)

And AC said, "LET THERE BE LIGHT!"
And there was light--

Isaac Asimov, "The Last Question"
(http://www.multivax.com/last_question.html)

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Ok, another physics question. Not related to the Big Bang, but I didn't
want to create a new thread.

  It seems that a black hole can be characterized by three (and only three)
quantities: its mass, angular momentum and electric charge. For example the
Reissner-Nordstr?m metric is a solution to the general relativity equations
for a charged, non-rotating black hole.

  I don't understand. Electric charge is mediated by photons. Photons cannot
escape a black hole. How can they mediate anything in this case? A black
hole swallows photons, it doesn't exchange them with anything.

-- 
                                                          - Warp

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And lo On Thu, 18 Nov 2010 15:53:38 -0000, Warp <war### [at] tagpovrayorg> did  
spake thusly:

>   This has puzzled me for a while, and I can't find an answer.
>
>   There was a time during the beginning of the Universe, when all the
> energy in the Universe was compressed into a space smaller than its own
> Schwarzschild radius.

As an aside to some the Big Bang theory is being dropped or at least the  
part where it derives from a singularity is.

There's inflationary theory (or theories) by which a quantum fluctuation  
inflates.

String theory (or the over-riding M-theory) whereby any attempt to  
compress an object beyond the Planck length will result in it expanding.

and Brane theory in which our universe is caused by either a collision or  
merging of two (or more) multi-dimensional 'sheets'.

All remove the need for a singularity.

As for your initial question, the calculations for the Schwarzschild  
radius don't apply to a rapidly expanding mass. As you put it the  
expansion out-runs the gravitational curve.

-- 
Phil Cook

--
I once tried to be apathetic, but I just couldn't be bothered
http://flipc.blogspot.com

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Le 23/11/2010 13:54, Phil Cook v2 a écrit :
> As you put it the expansion out-runs the gravitational curve.

I'm just nuts, and 10 cards short of full deck.


It seems gravitation has always been considered as "attraction between 2
objetcs".

What if, instead, it was just the universe which was repelling, and the
"mass" of the other object was in fact a shield against that repulsion.
(the more energy in the shield, the more protection it provide. and it
is just fine with delta-e=delta-m.c², but as a shield it only divert the
repelling flux: none get created, none get destroyed)

Remember the old joke: Gravity is a myth, the Earth sucks.

Well, in fact, it's just the universe which is blowing instead.

Gravity is a myth, the sky is pressuring you down!

Hence there is no graviton to find for the "fifth" force.
It's just made up from the known ones (the 4 united...)

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