Re: Gravitational field of a homogeneous universe
From: Eric Gisse (fsegg_at_!SPAMuaf.edu)
Date: 09/11/04
- Next message: mitch perkins: "Re: Can it be done? Operation Troll Shoulder"
- Previous message: Sam Wormley: "Re: Is Lorentz contraction objectively real?"
- In reply to: Bjoern Feuerbacher: "Re: Gravitational field of a homogeneous universe"
- Next in thread: Bjoern Feuerbacher: "Re: Gravitational field of a homogeneous universe"
- Reply: Bjoern Feuerbacher: "Re: Gravitational field of a homogeneous universe"
- Messages sorted by: [ date ] [ thread ]
Date: Sat, 11 Sep 2004 15:14:09 -0800
On Sat, 11 Sep 2004 17:12:07 +0200, Bjoern Feuerbacher
<feuerbac@thphys.uni-heidelberg.de> wrote:
>Eric Gisse wrote:
>> On Fri, 10 Sep 2004 12:39:56 +0200, Bjoern Feuerbacher
>> <feuerbac@thphys.uni-heidelberg.de> wrote:
>>
>>
>>>Eric Gisse wrote:
>>>
>>>[snip]
>>>
>>>
>>>>Ooh. I thought so!
>>>>
>>>>You just answered a question I have had for a long time and didn't
>>>>know how to answer.
>>>>
>>>>I always wondered if that insane amount of zero point energy was
>>>>affecting gravity or not. I didn't think so because it is the same
>>>>everywhere, but I didn't know how to prove it.
>>>
>>>Well, according to my results, this homogeneous dark energy does not
>>>contribute to the gravitational field of the universe - but it
>>>nevertheless influences expansion! (accelerating it)
>>>
>>>Strange result...
>>>
>>>Equally strange: a homogeneous universe filled with homogeneous matter
>>>or radiation (i.e. w >= 0) *also* has no influence on the gravitational
>>>field, but it *also* influences expansion! (decelerating it)
>>>
>>>
>>>Instead of solving a problem, you have opened up a new one, I think...
>>>
>>>
>>>Bye,
>>>Bjoern
>>
>>
>> This is the type of stuff I am highly interested in, but simply do not
>> have the raw math required to parse it. One class at a time...
>>
>> I am constantly amused by the predictions of quantum mechanics, one of
>> which is the Casmir effect. I love that, as it is a manifestation of
>> something through pure geometry.
>
>Nitpick: the Casimir effect is a prediction of Quantum Field Theory, not
>of Quantum Mechanics.
Oh :/
>
>
>> I think a proper question(s) to ask is/are : What if all the supposed
>> zero point energy was actually 'there', as in, it is actually
>> contributing to gravity? What physical effects would be manifested in
>> our universe according to GR and QM?
>
>I think one could get an answer to this question by trying to model
>the universe with something like a Schwarzschild metric instead of a
>Robertson-Walker metric, but I'm not sure about that.
>
>
>
>> Im going to muse for a minute about geometry. I should probably spawn
>> a thread about this.
>>
>> Im wonder if you know, as a person who is presumably educated much
>> more than me in the workings of QM, how often does pure geometry
>> appear in determining things?
>
>That question is rather vague. I don't understand what you mean exactly,
>sorry.
*ponder* how to phrase...
How often is it that the way a system acts is influenced almost
entirely decided by its' shape?
>
>
>> Things that do what they do because of a geometrical explanation [ie,
>> GR, Casimir effect, almost everything I have seen in math up to and
>> including today] are rather interesting
>
>Sorry, but what is the geometrical explanation for the Casimir effect?
Post badly phrased all 'round.
What I mean is that the geometry of particular cavity determines the
force - by changing the geometry you change what the effect does.
>
>
>> because they seem to take the
>> sense of being truly arbitrary out of the matter. There is wiggle room
>> within the bounds of the geometry, but your problems are firmly
>> bounded by it.
>>
>> I keep reading how various physicists thought everything was explained
>> by wave, then particle, then back to one or the other, then both -
>> throw in 'field' as you will. Im going with geometry...
>
>Did you know that one can describe classical electrodynamics using
>geometry? (fibre bundles)
No.
Interesting...
>
>
>> Everything mathematical I have seen has at least one geometrical
>> interpretation. Calculus? Linear algebra? Differential equations? All
>> of it has a geometrical explanation. [yes, that does pretty much sum
>> up my formal training in math :/ ]
>
>I think one could turn this around and say that every geometrical thing
>has an analytical interpretation, don't you think?
Yea.
That would explain why math handles the universe so well :D
>
>
>
>> What is our most successful theory of all time? Relativity. Relativity
>> itself is firmly 100% bounded by geometry.
>
>I would say QED, but that's a theory based on (Special) Relativity.
>
>
>
>> Look at the tools that we use to describe the universe. Math! Nothing
>> but math. The words we use merely explain the math to make it have a
>> little more sense. The math we use has roots firmly implanted in
>> geometry.
>
>Couldn't one say equally well that geometry is firmly rooted in math?
Yea.
>
>
>
>> There is one theme that seems to be carrying itself through both math
>> and physics: geometry. Im starting to think the universe is what
>> amounts to a geometrical manifestation.
>
>That stills sounds rather vague.
I know it does.
All I can say for *sure* is that in everything I see, geometry has a
very large influence either in explanation or interpretation.
>
>
>Bye,
>Bjoern
- Next message: mitch perkins: "Re: Can it be done? Operation Troll Shoulder"
- Previous message: Sam Wormley: "Re: Is Lorentz contraction objectively real?"
- In reply to: Bjoern Feuerbacher: "Re: Gravitational field of a homogeneous universe"
- Next in thread: Bjoern Feuerbacher: "Re: Gravitational field of a homogeneous universe"
- Reply: Bjoern Feuerbacher: "Re: Gravitational field of a homogeneous universe"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
