homogeneous/isotropic universe? "near enough"?

[sunshaker]

Universe homogeneous/isotropic?, Is near enough good enough?

 

I believe it was a good model, that now needs remodeling, Not stating has "gospel",

 

As our understanding increases certain models "have" to change, Some will always resist change. And hold on tight to a model that as served well.

 

I am not saying I have the answers, but I do believe sometimes you have to look with fresh eyes and without baggage.

 

Mordred quoted

 

 

the old value was 100Mpc the new value is 120 Mpc. At 120Mpc they no longer challenge the cosmological principle

 

but there are values that far exceed this 120Mpc, and there must be many we are yet aware of.

No structures are expected to be larger than the scale in accordance to the homogeneous and isotropic distribution of matter in the universe. However, in spite of this, some structures are discovered that exceed the scale consistently, such as:

The Clowes–Campusano LQG, discovered in 1991, is 630 Mpc across, and is marginally larger than the scale.

The Sloan Great Wall, discovered in 2003, has a length of 423 Mpc,^[11] and is also marginally larger than the scale.

U1.11, another large quasar group discovered in 2011, is 780 Mpc across, and is two times larger than the scale.

The Huge-LQG (Huge Large Quasar Group), discovered in 2012, has a length of 1.24 Gpc, and is three times larger than the upper limit of the homogeneity scale.^[12] However, the scales of the individual quasars of this structure do not have a chance correlation to each other, providing the evidence of the impossibility of this structure.^[13]

The Hercules–Corona Borealis Great Wall is more than eight times larger than the scale,^[4] greatly exceeding the homogeneity scale. In accordance with this, the structure would still be heterogeneous as compared to the other parts of the universe even at the scale of the "End of Greatness", thereby putting the cosmological principle into further doubt.

 

coherent oscillations strongly support the idea that the first inhomogeneities in the universe were seeded during the accelerated expansion stage called inflation. The results of WMAP also challenged two of the basic assumptions of the standard cosmological model, isotropy and homogeneity.

Indications collected by WMAP for deviations from isotropy and homogeneity on very large scale have been confirmed with Planck

 

 

 

Cosmologists are now facing an interesting dilemma: on the one hand, the standard model of cosmology is still the best way to describe the CMB data, although it includes elements that still lack solid theoretical understanding such as dark matter, dark energy, and inflation. On the other hand, the anomalies seen by Planck highlight that the model should be at the very least extended, if not radically modified. http://sci.esa.int/planck/51551-simple-but-challenging-the-universe-according-to-planck/

What I am trying to say is when some posters throw up that someones idea/theory does not match with an homogeneous/isotropic universe, Neither does our universe on certain scales.

 

This inability in a few to see past a homogeneous/isotropic universe(without exception), closes for them new avenues to explore and understand.

 

Nothing yet is written in stone as fact. Science builds upon science, But sometimes science needs the "old guard" to die of before new ideas can really flourish.

 

Roger G. Clowes at the University of Central Lancashire

 

 

explaining that the cosmological principle has "seemed plausible, but it's never really been demonstrated beyond reasonable doubt." Over time we have tried to tinker with the homogeneity scale of the cosmological principle to accommodate for unusually large objects. "But," Clowes writes, "this is a few percent of the size of the observable universe, so we might not be able to do that kind of thing any more."

Edited October 30, 2014 by sunshaker

[Mordred]

Sorry I didnt see your post glad you started a new thread on the subject.

 

Here is the thing about homogeneaty.

 

"At a sufficiently large enough scale the universe appears to be the same throughout."

 

what this means in a nutshell is that if one scake does not give the appearance of homogeneaty in measurements. Back on the 80's that scale was roughly 100 Mpc. Some textbooks today still publish that value. One such is Barbera Rydens "Introductory to cosmology"

 

however later challenges such as the Sloan great wall forced that scale to increase. Irregularities can still be present. There is a homogeneaty function calculation that is sometimes used to determine what the scale should be set at.

 

Now Liddle makes an excellent point on this page.

 

"physical structures do not necessarily need ti be homogeneous as long as the laws of physics are the same" (not an exact quote) working from phone atm.

 

What this means is that rates of expansion thermodynamic properties are still homogeneous

 

therefore the FLRW metrics, the Einstein field equations the ideal gas laws, power law spectrums ie CMB etc are all still homogeneous despite the presence of those irregularities.

 

None of the major models such as the LCDM model lose any predictive power as a result.

 

if they do then you can still increase the scale. However last I heard 120Mpc is still sufficient. Could or could not be higher now.

hope that helps

 

http://en.m.wikipedia.org/wiki/Cosmological_principle

Quote is the second principle

Now considering ghose discoveries we still see recent and up to date articles written in accordance with the cosmological principle by the top physicists in the world today. They are all aware of these discoveries and they still adhere to the cosmological principle. Both the Planck data and the recent Bicep data still find a strong agreement with the cosmological principle. These data sets were both published after those discoveries. So evidentally the cosmological principle is still accurate to a high sigma level that those structures are not a concern

(really wish my operating system on my laptop hadn't crashed I had a specific paper on the subject that came out after the last find) it was an arxiv paper and suggested a scale increase to 200 Mpc however I have yet to see any further changes in current articles on the scale perhaps someone else has

By the way the Planck south pole anistrophy was found to be a calibration error.

 

Forgot to add the 2012 quasar cluster is at z=1.3 believe thats the right one. Anyways the universe was 4.77 Gly where thats located so the sverage density is naturally higher just a side note it was still considered a challenge by some

Side note FYI 2 the rate of expansion was slowing down as this is part of the matter dominant era. The lambda dominant era starts at 7.3 Gly and the rate of expansion starts to accelerate.

Edited October 31, 2014 by Mordred

[ajb]

Universe homogeneous/isotropic?, Is near enough good enough?

It is a good approximation on the large scale; roughly at the scale at which you can consider clusters of galaxies as points. In fact, from these approximations you get the FLRW cosmologies independent of any specific theory or matter content.

[imatfaal]

...

The results of WMAP also challenged two of the basic assumptions of the standard cosmological model, isotropy and homogeneity.

Indications collected by WMAP for deviations from isotropy and homogeneity on very large scale have been confirmed with Planck

...

 

Whilst the amazing data gathered by WMAP does show anisotropy - the level of variation is pretty tiny; around the order of one part per million. The cosmological principle is more a working assumption that makes physics possible - rather than a law that some might see as set in stone.

[sunshaker]

Here is the thing about homogeneaty.

 

"At a sufficiently large enough scale the universe appears to be the same throughout."

 

 

At sufficiently large and small scales many things appear the same throughout"

Before I go any further, I would just like your view on how you would define a lung, viewed at universal scales, would you say it is homogeneous/isotropic ?

 

I am not saying our universe is a lung, But if we existed where I have circled, Would we view our universe as homogeneous/isotropic, existing on a single in breath, would we know where that inbreath came from.

Edited October 31, 2014 by sunshaker

[ajb]

Before I go any further, I would just like your view on how you would define a lung, viewed at universal scales, would you say it is homogeneous/isotropic ?

At a certain scale it does indeed look homogeneous and isotopic. Basically it all looks continuous and uniform. It is only when you zoom in do you see the filament structure here.

[Strange]

And it is only when you zoom out that you see the boundaries. As far as we know, the universe has no boundaries.

[sunshaker]

And it is only when you zoom out that you see the boundaries. As far as we know, the universe has no boundaries.

Because we have not yet been able to "zoom out" to see if our universe has boundaries,

The lung is still a part of another system. But seems homogeneous/isotropic at certain scales from within.

 

Just because what we can "observe seems to be homogeneous/isotropic", does not dismiss an "outside influence",

[ajb]

Just because what we can "observe seems to be homogeneous/isotropic", does not dismiss an "outside influence",

And people have considered various cosmologies, such as brane worlds and allowing interactions with 'other' universes and so on.

[Strange]

Because we have not yet been able to "zoom out" to see if our universe has boundaries,

 

True. And we will probably never be able to. But our current models include no boundaries. It is a reasonable working assumption (even if untestable) that the universe beyond he visible universe carries on much the same. Although it may change on very large scales, there is no reason to throw away the "approximately homogeneous" model - until it is found not to work.

[sunshaker]

 

True. And we will probably never be able to. But our current models include no boundaries. It is a reasonable working assumption (even if untestable) that the universe beyond he visible universe carries on much the same. Although it may change on very large scales, there is no reason to throw away the "approximately homogeneous" model - until it is found not to work.

Which is why I think we should be spending more time understanding these structures that do not fit this model, .

 

Hercules–Corona Borealis Great Wall http://en.wikipedia.org/wiki/Hercules%E2%80%93Corona_Borealis_Great_Wall#cite_note-conundrum-4

Which is aprox 10.7% of observable universe.

 

 

The newly discovered structure, however, just doesn't simply fit to the model; the structure is so big, so complex, and so massive to exist even under the standard models of the evolution of the universe. In addition, one must also note that the light travel distance of 10 billion light years means that we see the structure as it was 10 billion years ago, or roughly 3.8 billion years after the Big Bang. Current models of the universe's evolution, however, do not allow the said structure to form in just a mere 3 billion years, since this is a very short time for dark matter to attract sufficient baryonic matter to create the giant structure. The structure is itself too big, and too complex, to exist so early in the universe. There is currently no existing model to explain the existence of the structure.

Which remind me of the valves of the lung in above picture, "still not saying our universe is a lung", just how similar the structure is at certain scales.

 

But now i must spend some time understanding this " Hercules–Corona Borealis Great Wall" and similar structures.

[Strange]

Which is why I think we should be spending more time understanding these structures that do not fit this model

 

Why do you think that not enough time is being spent on these structures? How much is "enough"? What other areas should be dropped in favour of these?

 

I don't expect you to answer those, but it's just to point out that all research work is a balance of resourcing, potential value, interest, feasibility, politics, and many other factors. No one person gets to decide what should be focussed on.

[sunshaker]

 

Why do you think that not enough time is being spent on these structures? How much is "enough"? What other areas should be dropped in favour of these?

 

I don't expect you to answer those, but it's just to point out that all research work is a balance of resourcing, potential value, interest, feasibility, politics, and many other factors. No one person gets to decide what should be focussed on.

I would believe they are of "great potential value, interest", But I also understand the "politics + funding issues",

 

What I interesting was when i came across what some students of "extragalactic astronomy" had wrote that these anomalies had not been brought up in their classes, but had been ignored.

Edited October 31, 2014 by sunshaker

[ajb]

What I interesting was when i came across what some students of "extragalactic astronomy" had wrote that these anomalies had not been brought up in their classes, but had been ignored.

It is not unusual in undergraduate studies not to discuss in great detail the physics right on the boundary of understanding. If the issues are not sorted then one has to be careful introducing them in class. Also, depending on the subject, undergraduates may simply not have the knowledge to discuss the latest findings and thinking.

[Mordred]

The key issues have already been answered but lets touch upon the related physics altering issues.

 

we will use the largest quasar group. Lets look at what those quasars influence in terms of the FLRW metric specifically. (which includes the ideal gas laws)

 

first the influence upon gravity of each quasar is a local influence not a global one. Gravities strength quickly reduces the further you move from an object. The gravity drops off fast enough that the individual quasars within that group are not affected by each other.

 

now the influence upon the local energy density.

 

for this we need the equation of state for matter.

If you google equation of state cosmology yiu can easily find the wiki page.

 

matter whether its baryonic or non baryonic exerts next to zero influence upon pressure. So this means that the pressure in those regions and the subsequent energy density of those regions is no different than anywhere else.

So in terms of universe geometry, curvature, localized temperature and average energy density those regions are still uniform compared to everwhere else.

 

Therefore the ideal gas laws, FLRW metric, Einstein Feild equations, LQC equations etc all still work to the same degree of accuracy.

 

As they all still work to a good approximation (no equation is pefect in the ideal gas laws) then why change them?

[sunshaker]

 

matter whether its baryonic or non baryonic exerts next to zero influence upon pressure. So this means that the pressure in those regions and the subsequent energy density of those regions is no different than anywhere else.

So in terms of universe geometry, curvature, localized temperature and average energy density those regions are still uniform compared to everywhere else.

 

Therefore the ideal gas laws, FLRW metric, Einstein Field equations, LQC equations etc all still work to the same degree of accuracy.

 

As they all still work to a good approximation (no equation is perfect in the ideal gas laws) then why change them?

Which I agree with, But it is still not perfect, Nor does it explain these anomalies which are not understood, Or rule out an outside influence.

 

MORDRED QUOTED

 

 

In our universe the average energy density and rate of expansion are the same regardless of location. There is no preferred location or direction either. Dark energy of vacuum energy is constant regardless of location within our universe

Where you stated this as proof that dark energy cannot be an "outside" force of our universe.

 

I mostly agree "dark energy is constant regardless of location within our universe",

 

But even if dark energy is an outside force coming into our universe, Which I think it may be(and perhaps explain some of these anomalies), There is no reason why it would not be "constant regardless of location within our universe" in terms of "universe geometry",

 

If universe is expanding within a dark energy field, the energy properties of dark energy would not change, Only fill the expanding universe,

As the dark energy fills the universe there would be no preferred location or direction, Except maybe a few "anomalies" where it first enters universe.

 

In pic below, showing sample area of universe/dark energy, I have placed the milkyway and do not think there would be a preferred location or direction of dark energy.

And universe would still be homogeneous/isotropic, at least on scales we understand.

[Mordred]

You have to look at it in terms if pressure tske a balloon place it into a vacuum chamber. Then increase the vacuum pressure. The gas inside the balloon will expand outward. Anistropic we have a preferred direction. As objects and gas must move slower than c you would also be inhomogeneous as the universe adjusts to the new volume. The outer regions will inititially adjust first and progressively adjust inward. remember even information is limitted to c. So there is no way the universe could maintain a continous balance to an outside pressure to itself

 

the cosmological constant however develops everywhere equally. As new volume becomes becomes equally available at all locations in accordance to the cosmological principle the metrics of isotropic and homogeneous expansion is preserved.

The rate of expansion per unit volume regardless of location is the Hubble constant. Whuch is constant everywhere at a particular time only. It can be different tomorrow or in the past but must be the same everywhere.

 

Now if there was a mechanism of quantum tunneling involved where the arrival destinations were homogeneous and isotropic then an outside pressure influnce could lead to a homogeneous and isotropic model.

 

Side note the problem facing the model idea your referring to is identical to the pronlems that caused me to abandon my natural pressure dispertion model

[sunshaker]

You have to look at it in terms if pressure tske a balloon place it into a vacuum chamber. Then increase the vacuum pressure. The gas inside the balloon will expand outward. Anistropic we have a preferred direction. As objects and gas must move slower than c you would also be inhomogeneous as the universe adjusts to the new volume. The outer regions will inititially adjust first and progressively adjust inward. remember even information is limitted to c. So there is no way the universe could maintain a continous balance to an outside pressure to itself

 

the cosmological constant however develops everywhere equally. As new volume becomes becomes equally available at all locations in accordance to the cosmological principle the metrics of isotropic and homogeneous expansion is preserved.

The rate of expansion per unit volume regardless of location is the Hubble constant. Whuch is constant everywhere at a particular time only. It can be different tomorrow or in the past but must be the same everywhere.

 

Now if there was a mechanism of quantum tunneling involved where the arrival destinations were homogeneous and isotropic then an outside pressure influnce could lead to a homogeneous and isotropic model.

 

Side note the problem facing the model idea your referring to is identical to the pronlems that caused me to abandon my natural pressure dispertion model

I understand where you are coming from with the "ballon/gases",

 

"maybe a poor metaphor"

but I see more along the lines, of like if you dropped say a dog biscuit in the ocean, the biscuit being porous to water, expanding biscuit, the energy of the water would not change as the biscuit "expands equally everywhere at once" . until when the "biscuit/dark matter" eventually breaks completely down and can no longer hold together, and becomes a few molecules in a ocean of water.

 

As we believe the "universe" at the start was infinitely small, at that first moment of rapid expansion dark energy/field would have been everywhere at once, the universe/dark energy already "homogeneous/isotropic".

 

I see it as we are living within the time scales of virtual particles that pop in and out of existence, to us on our scales of time/measurements billions of years, when in reality the universe is no more than a virtual particle in a sea of particles.

 

life in the near freeze frame of a virtual particles short existence.

 

 

 

Now if there was a mechanism of quantum tunneling involved where the arrival destinations were homogeneous and isotropic then an outside pressure influnce could lead to a homogeneous and isotropic model.

In a previous thread I said i believed black holes/gamma ray bursts where one of the processes to keep the universe expanding evenly, sometimes consuming sometimes expelling energies to different areas of universe, one of the reasons i believe why each galaxy as a super massive black hole at its center, along with varying size black holes down to the microscopic/quantum levels.

 

Black holes, the universe regulators/pores.

 

 

 

Side note the problem facing the model idea your referring to is identical to the pronlems that caused me to abandon my natural pressure dispertion model

I would like to have a read of your model, And see for myself why you chose to abandon it, is it in this forum?

Edited November 1, 2014 by sunshaker

[Mordred]

I did the work on my laptop which recently crashed. The gist of the model is as follows

 

any energy density region higher than a ground state. Ground state being e=1/2hv due to the uncertainty principle. Any energy regions higher than this will spread out until it reaches the ground state. In order to deal with the homogeneaty and isotropy issue and speed of information exchange I used the false to true vacuum process and quantum tunneling.

 

the problem with that however is the amount of energy transferred via tunneling from false vacuum to true vacuum is the difference between the two. So as one region balances to another region the energy exchange changes. Unfortunately the cosmological constant is constant this is the part I couldnt find a solution to.

 

However I havent completely abandonned it. Cutrently I am studying the thermodynamic contributions to the Higgs field itself. The Higgs field is already evenly dispersed so its interactions will contribute to the universes temperature. This strikes me as a more promising possibility than the model I just described for one thing quantum tunneling isnt needed.

 

When your dealing with something the size of the universe. information exchange rate is limitted to c quantum tunneling doesnt allow a faster exchange which is another problem.

 

the rigid rod of relativity is a good analogy. Take a rod 1 light year in length. Move one end of the rod. It will take 1 light year before the other end moves.

 

quantum tunneling doesnt fix this problem

I never posted the model as its one I can disprove

 

I come up with an idea to solve a problem in it then research the idea. Then I apply the mathematics with several different related metrics. Those metrics usually point out a problem in the model.

Keep in mind I learned a lot from when I first started the model till today. 2 years ago I thought information could be exchanged faster than c via quantum tunneling.

[sunshaker]

My understanding of "virtual particles", are they come from the planck/sub scales, Scales which the "Higgs inhabits",

 

 

When talking about quantum fluctuation/vacuum energy being responsible for the cosmological constant. I cannot help but feel virtual particles play a major role,

If virtual particles are really universes at planck scales popping into existence everywhere at all times, with the same physics as our universe just many magnitudes of scale smaller, with lifetimes measured to us in planck time, before becoming/adding to this universes vacuum/space, keeping the cosmological constant constant.

 

If our universe is also a virtual particle in another universe many magnitudes larger, our universe would leave behind all this expanded space/vacuum energy, which would add to the vacuum of the universe we are expanding within, Similar to a hologram where each part of a hologram contains the whole.

 

As more space/vacuum is added to each universe by "virtual universes" there will then be more space for virtual particles/universes to come into existence, which would slowly speed up each universe expansion from within.

 

 

Virtual universe, universes fueled by universes.

[Mordred]

I would have a hard time thinking of them as mini universes. Lol anyways virtual particles share the same characteristics of real particles just extremely short lived. They are thought to be produced in a wide range of methods. Blackholes with Hawking radiation. as well as Unruh radiation. Parker radiation (older inflation model)

The inflaton (chaotic eternal inflation) curvaton (cant recall which inflation model). There is also one produced at magnitars due to magnetic perturbations. And the Casimar experiment.

 

there is probably more the zero energy universe is also based on virtual particle production.

 

Then you have QMs zero point energy. E=1/2hv which involves the Heisenburg uncertainty principle snd the harmonic oscillator.

 

The later particle physics model SO(10) may hold an answer involving the Higgs metastability and its seesaw mechanism. There have been numerous papers posted on the subject.

[url=http://www.scienceforums.net/topic/83765-higgs-field-thermodynamic-research-cmb-and-now/#entry811661]http://www.scienceforums.net/topic/83765-higgs-field-thermodynamic-research-cmb-and-now/#entry811661[/url

 

anyways my current research has changed due to Higgs studies. The later SO(10) model may hold the key to inflation as well as the cosmological constant due to the Higgs metastability. Here is an older post in regards to what I am still researching and the direction I am now looking into link at top. This has far better promise than my failed model

As far as cosmological constant driven by virtual particles from another it could be homogeneous,isotropic and constant the problem is obviously does a multiverse exist? but thats a lengthy topic that tends to lead to answers based on philosophy rather than physics physics is certainly the emphirical evidence isn't there

Edited November 2, 2014 by Mordred