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Author | Topic: The infinite space of the Universe | |||||||||||||||||||||||||||
Straggler Member (Idle past 93 days) Posts: 10333 From: London England Joined: |
Ok, for those with an actual interest in 'an' answer, the problem is what fields are we considering for this vacuum? If we're just talking about the 'basic' linear matter/force fields (quantum electrodynamics- i.e. photons & electrons) with a flat background metric (space-time), then we have the simple quantum vacuum state of the fields. There are no real particles in the vacuum state, but the fields are certainly not zero valued as is demonstrated by the Casimir Effect (by reducing the field vacumm fluctuations below that of the true vacuum).
I am interested. This simple picture grows vastly more complicated when we hit the non-linear fields of Quantum ChromoDynamics and gravitation - their vacuum structures form global non-trivial backgrounds.Where does the weak nuclear force fit into this? Does that have a field presence in the vacuum too? Do all 4 fundamental forces have an ever present field presence in every point of the vacuum? How does the answer to this relate to a possible theory of everything? This simple picture grows vastly more complicated when we hit the non-linear fields of Quantum ChromoDynamics and gravitation - their vacuum structures form global non-trivial backgrounds.
How does gravitataion have a field effect in the vacuum of curved spacetime when gravitation is curved spacetime? I am missing something fundamental here as this doesn't make sense to me?
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ICANT Member Posts: 6769 From: SSC Joined: Member Rating: 1.6 |
Hi CS,
Catholic Scientist writes: What's wrong with absolute nothingness being an impossibility? How is it a "paradox"? What is wrong? We are Here. If there was ever a time that there was absolute nothingness (an absence of anything) It would still be. Energy can not be created therefore it had to always exist. Or it can be created out of an absence of anything. God Bless, "John 5:39 (KJS) Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me."
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cavediver Member (Idle past 3671 days) Posts: 4129 From: UK Joined: |
Where does the weak nuclear force fit into this? Does that have a field presence in the vacuum too? Yes, it is another non-linear set of fields. This is where vacuum studies get very interesting as you're into the world of spontaneous symmetry breaking and the Higgs mechanism (and associated Higgs boson of course) In its most symmetrical state, what we think of as the electrodynamic fields (photons, electron, etc) are wrapped up into the eletcroweak fields. But this is not the lowest energy state. The true vacuum of the electroweak fields breaks the symmetry and we get the weak force and electrodynamics effectively splitting apart.
Do all 4 fundamental forces have an ever present field presence in every point of the vacuum? Yes, though replace 'vacuum' with 'space-time' and you have the basic idea.
How does the answer to this relate to a possible theory of everything? Well, a theory of everything at the very least has to unify the four 'force' fields and all the related matter fields into one master field.
How does gravitataion have a field effect in the vacuum of curved spacetime when gravitation is curved spacetime? Ok, ready to go deep? Reality as we see it is simply a multi-layer of fields. There is some pre-existing topology, so for example lets assume these fields are wrapped into a sphere (surface of a sphere), but its more like a stretchy empty bean-bag in that there is no concept of shape, geometry or distance - jut global topology. One field gives rise to a concept of 'distance'; at each point in the field, its values give the distance between neighbouring points at that location. Over the entire surface, this gives rise to the global shape, curvature and large scale distance. This is the gravitational or metric field. Its local values are given as a function of the values of the other fields at that point and the neighbouring values of its own field. Local fluctuations in this field give rise to gravitational waves, and at the qunatum scale, gravitons. The other fields are the ones we discussed above. This is the totality of reality. What we think of matter, space, vacuum, particles, people, stars, voids, curved space-time, etc, are all just aspects of this layer of fields. Edited by cavediver, : No reason given.
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Brad McFall Member (Idle past 5060 days) Posts: 3428 From: Ithaca,NY, USA Joined: |
Thanks, I guess I am getting better with physics. That is pretty close to what I could have thought.
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New Cat's Eye Inactive Member |
The fact that black holes do have mass does not rule out the possibility that they constitute true "nothingness". It's a contradiction!
If the word nothingness does not signify anything meaningful, then there is no need for such a word. However, the word can be found in every dictionary and that is a paradox. Its just a concept. Like absolute zero on the temperature scale. Nothing can ever really get to absolute zero but the concept exists as a benchmark.
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New Cat's Eye Inactive Member |
Catholic Scientist writes: What's wrong with absolute nothingness being an impossibility? How is it a "paradox"? What is wrong? We are Here.
What's wrong with it being an impossiblity?
If there was ever a time that there was absolute nothingness (an absence of anything) It would still be. Yupp. So nothingness is impossible.
Energy can not be created therefore it had to always exist. Or it can be created out of an absence of anything. Or two things that aren't energy themselves combine to become energy, like two branes colliding. You're creating a flase dichotomy of either nothingness or eternal energy so that you can claim god. But lets ust leave god out of this thread, okay?
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New Cat's Eye Inactive Member |
Reality as we see it is simply a multi-layer of fields. There is some pre-existing topology, so for example lets assume these fields are wrapped into a sphere (surface of a sphere), but its more like a stretchy empty bean-bag in that there is no concept of shape, geometry or distance - jut global topology. One field gives rise to a concept of 'distance'; at each point in the field, its values give the distance between neighbouring points at that location. Over the entire surface, this gives rise to the global shape, curvature and large scale distance. This is the gravitational or metric field. Its local values are given as a function of the values of the other fields at that point and the neighbouring values of its own field. Local fluctuations in this field give rise to gravitational waves, and at the qunatum scale, gravitons. The other fields are the ones we discussed above. This is the totality of reality. What we think of matter, space, vacuum, particles, people, stars, voids, curved space-time, etc, are all just aspects of this layer of fields. When they talk about the "bulk" in brane cosmology here:
quote: Are they postulating that the multi-layer of fields exists within something else?
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cavediver Member (Idle past 3671 days) Posts: 4129 From: UK Joined: |
Are they postulating that the multi-layer of fields exists within something else? I didn't actually specify a dimension of the reality before, but I guess we all assumed it was 4 dimensional (or 3 + time, depending on how you were picturing it.) In a string/brane/M context, the dimension would be 10 + time, and our reality would exist as a 4d sub-slice of this higher-d space. So the effective fields that we see in 4d are only part of the real 11d fields. The bulk is the whole 11d space. Your quote is explaining that the effective 4d gravity is decomposed from the 11d in a slightly different way to the other effectuve 4d forces.
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New Cat's Eye Inactive Member |
Your quote is explaining that the effective 4d gravity is decomposed from the 11d in a slightly different way to the other effectuve 4d forces. I got that part.
In a string/brane/M context, the dimension would be 10 + time, and our reality would exist as a 4d sub-slice of this higher-d space. So the effective fields that we see in 4d are only part of the real 11d fields. The bulk is the whole 11d space. This answers my question. Thanks. I wasn't sure if the 11d was the bulk or if the 11d was in the bulk, so to speak.
I didn't actually specify a dimension of the reality before, but I guess we all assumed it was 4 dimensional (or 3 + time, depending on how you were picturing it.) Does the multi-layer of fields fall apart if you assume 11d instead of 4?
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cavediver Member (Idle past 3671 days) Posts: 4129 From: UK Joined: |
Does the multi-layer of fields fall apart if you assume 11d instead of 4? No, not at all. SuperGravity was our original attempt at an 11d theory of everything, which was essentially just a Grand Unification of all of the fields, including gravity. Now we suspect that there is something deeper than a 'simple' unification that gives rise to the picture of fields that I have described - string theory/M-theory being possibly behind this.
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ICANT Member Posts: 6769 From: SSC Joined: Member Rating: 1.6 |
Catholic Scientist writes: Or two things that aren't energy themselves combine to become energy, like two branes colliding. So are saying two branes are an absence of anything? So how did they collide? God Bless, "John 5:39 (KJS) Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me."
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New Cat's Eye Inactive Member |
So are saying two branes are an absence of anything? What!? Are you joking? Of course they're not.
So how did they collide? I dunno. I was just pointing out that your two possibilities are not the only ones.
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GDR Member Posts: 6202 From: Sidney, BC, Canada Joined: Member Rating: 2.1 |
If they are able to find the Higg's bosun with the LHC will it move us very much closer to the TOE? Is it likely that they will find anything else that might help as well?
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cavediver Member (Idle past 3671 days) Posts: 4129 From: UK Joined: |
If they are able to find the Higg's bosun with the LHC will it move us very much closer to the TOE? No, but not finding it might well do so
Is it likely that they will find anything else that might help as well? Yes, there are many possibilities, from supersymmetric partners of the standard model particles (photinos, winos, zinos, selectrons, squarks, etc) to min black holes - lots of exciting stuff
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onifre Member (Idle past 2978 days) Posts: 4854 From: Dark Side of the Moon Joined: |
If they are able to find the Higg's bosun with the LHC will it move us very much closer to the TOE? Is it likely that they will find anything else that might help as well? No, not in relation to the Theory of Everything. The Higgs, as I understand it, came after T=O. It will however, help us better understand the expantion. All great truths begin as blasphemies
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