What fuels accelerating expansion of our universe

[matt.o]

Did you read Henry's slides? The conclusion was that clusters provide independant fits to current cosmological models.

 

[Chronos]

Pray tell who thinks there is any 'standard model' that explains it all? There are far more questions than answers and the assertions cosmologists do make are carefully nestled among many caveats. Characterizing mainstream opinion as the "dark side" of orthodox cosmology is reckless and dismissive of the intellect, integrity and sacrifices made by the people who comprise the scientific community.

 

[turbo]

Pray tell who thinks there is any 'standard model' that explains it all? There are far more questions than answers and the assertions cosmologists do make are carefully nestled among many caveats. Characterizing mainstream opinion as the "dark side" of orthodox cosmology is reckless and dismissive of the intellect, integrity and sacrifices made by the people who comprise the scientific community.

Maybe I should have put a "smilie" after the "dark side" comment, so you would recognize it as a jab about the comfort with which some folks swallow the concepts of DARK energy and DARK matter without demanding some independent evidence of their existence. When clusters are shown by gravitational effects to have 100 times the mass that we can detect, something is wrong with our understanding of gravity.

 

[Chronos]

You're right, turbo, I need to be degaussed occasionally :grumpy: . What we really can't rule out at this point in time is the possibility clusters really do possesses as much gravitating mass as their motions suggests. Granted, most of that mass is not observable in the EM spectrum, but, there are other observations [e.g., WMAP] that also suggest there is a great deal of unseen mass in the universe. A good bit more work is needed before it is safe to assume we have falsified the existing model of gravity.

 

[Mike2]

I suppose such a process would be a purely mathematical consideration: what mathematical processes give rise to the growth of a manifold (or a space) from a singularity. There are homotopy classes that describe which kinds of manifolds (spaces) can be continuously shrunk down to a singularity, which manifolds can be continuously shrunk down to a closed line, a surface, etc. So no doubt there are some homotopy considerations involved with the possible spaces (manifolds) that can arise from a singularity.

Continuing from:
https://www.physicsforums.com/showpost.php?p=507583&postcount=4

If every point in space must be within the zeroth homotopy class of every other point, does this constitute a symmetry of some sort. What kinds of mathematics should I study to learn more about these questions? Thanks.

 

[cyjuan_m]

I have new theory

It is possible that just like magnetism there's a force of repulsion for gravitation. Which instead of bending space is pushing matter apart. I call anti-gravitation. I know that gravitation is not force but if gravitation is the consequence of matter. Where there’s no matter, gravitation couldn’t exist so anti-gravitation take its place. But I have to prove it mathematically and that is going to be hard. I thing the key is in quantum mechanic because all the energy can't just disappear and since all universe is connected it is possible that energy would get together somehow.

 

[turbo]

It is possible that just like magnetism there's a force of repulsion for gravitation. Which instead of bending space is pushing matter apart. I call anti-gravitation. I know that gravitation is not force but if gravitation is the consequence of matter. Where there’s no matter, gravitation couldn’t exist so anti-gravitation take its place. But I have to prove it mathematically and that is going to be hard. I thing the key is in quantum mechanic because all the energy can't just disappear and since all universe is connected it is possible that energy would get together somehow.

Welcome cyjuan_m!

If gravitation is a consequence of the presence of mass (with no underyling mechanics) then we will have to assume (as Einstein did) that mass can warp spacetime. GR gravitation is a good mathematical approximation, but it is incomplete, because there is no explanation of the underlying engineering that produces gravitational attraction. This is a problem in the standard model, in that gravitation is popularly modeled as an attractive force mediated by gravitons or Higgs Bosons. We have not yet discovered these mediating particles, despite performing years of particle experiments at energies far above those at which these particles should have been detected. Perhaps the theories that predict the existence of these particles is wrong.

It is perhaps possible that "anti-gravitation" is the quantum behavior of particles at the Planck scale that provide a dynamical balance between gravitation and quantum effects. For instance, the Pauli Exclusion Principle supports the existence of white dwarf stars because electrons cannot occupy the same quantum states and resist gravitational compression. If the collapsing star is very large, the gravitational compression will force the electrons to merge with protons to form neutrons, in the form of a neutron star. Neutrons have even more rigorous resistances to occupying the same energy state, allowing the Pauli Exclusion Principle to prevent the further collapse of the neutron star.

If the Pauli Exclusion Principle can cause gravitation and nuclear forces to come to a dynamical balance in highly-massive domains, we should expect that they can do the same in a rarified domain, like "empty" space.

 

[cyjuan_m]

probably this particles don't exist in this universe, but in another dimension. I think I 've read somewhere that particles can coexist in different dimention since the effect of gravitation is very little they can cross between dimentions.

 

[Mike2]

Continuing from:

https://www.physicsforums.com/showpost.php?p=558775&postcount=40

If every point in space must be within the zeroth homotopy class of every other point, does this constitute a symmetry of some sort. What kinds of mathematics should I study to learn more about these questions? Thanks.

If this is a symmetry, then I suppose that the symmetry breaking would produce matter due to changes in homotopy for some point with respect to some others. I wonder if this scenario only works if each dimension of homotopy must have a Lorentzian metric? I'm encouraged by the link between entropy and singularities for only those manifolds that expand in

http://search.arxiv.org:8081/paper.jsp?p=math.DS/0505019&qid=1116295216853-1270101189

I will have to do more study to complete this picture. Or maybe someone else would like to do the math. It looks similar to the Dynamical Triangulation effort where (IIRC) they use simplecial structures in the limit to the infinitesimal homomorphic to the manifolds of differing dimension in my scenario that are collapsible to a point, the original singularity from which all things must have come. You are welcome to correct my misconception, of course.

Is this the place for this discussion? Or do I need to start a new thread, or put it in a different forum? Thanks.

 

[selfAdjoint]

I don't know what you mean by the zero homotopy class of a point. Just connectivity? Homotopy classes are discussed in algebraic topology. I think there are some popular intorductions to the field.

 

[Mike2]

I don't know what you mean by the zero homotopy class of a point. Just connectivity? Homotopy classes are discussed in algebraic topology. I think there are some popular intorductions to the field.

I might be wrong about "zeroth" homotopy class; I thought I remember reading that term, Oh well. Maybe I mean a superposition of various dimensional manifolds that are each collapsible to a point.

Do you agree that this sounds attractive: the universe must be a manifold, or superposition of manifolds, that come from a single point? And if there is no a priori reason to select a particular dimension, then all dimensions should be considered in some sort of superposition? To me this sounds inescapable, the only alternative is to suppose the instant creation of some size manifold. Expansion from a point sounds natural to me. The 4D world may be an average or expectation value derived from the ensamble of various dimensional manifolds? I think one of the key points is that one never knows which point was the first to arise and so physics must be invariant with respect to which point in space came first in the expansion of the universe.

It may be that the "interference" between these various expanding manifolds is what produces particles. No, I don't really know what I'm talking about. But perhaps since each point is the orgin of manifolds, the "interference" between them gives rise to the path integral formulation of QM. I picture an expanding manifold not quite melding together with the others and producing a break in zeroth homotopy to produce a first or fundamental homotopy clase which acts like a particle.

I think I'd need a PhD in Mathematics and Physics to even investigate this. Or maybe this all sounds familiar to some of you. What are the prerequisites for algebraic topology? Thanks.

 

[Garth]

No, I don't really know what I'm talking about.

With Dark Matter, Dark Energy, quintessence, colliding branes, leaking dimensions, multiverses, etc. etc. Does anybody?

Garth

 

[Mike2]

I might be wrong about "zeroth" homotopy class; I thought I remember reading that term, Oh well. Maybe I mean a superposition of various dimensional manifolds that are each collapsible to a point.

Or at least any two points have to exist on manifolds that are collapsible to a point. But if the point that each manifold is collapsible to also exist, then perhaps this is the same as above.

I think one of the key points is that one never knows which point was the first to arise and so physics must be invariant with respect to which point in space came first in the expansion of the universe.

Or perhaps this can be modified to say that the probability that a point originated from the expansion of another point is dependent on how far that point is from the other. Nearby points are more likely to originate from nearby expansion than from expansion from far away points. This would imply a metric. This would also be a means of assigning a probability function to the various possible manifolds from which points emerge during expansion. And isn't a superposition of various possible spacetime manifolds exactly what is needed to derive quantum gravity, right?

 

[Zanket]

With Dark Matter, Dark Energy, quintessence, colliding branes, leaking dimensions, multiverses, etc. etc. Does anybody?

Good one. Cosmologists do a great job of sounding like it's all a forgone conclusion though. I'm going to hate to see my taxes going to look for dark energy.