Why we've got the cosmological constant all wrong

Mar 05, 2012 by Lisa Zyga feature
Effective field theory incorrectly predicts the value of the cosmological constant, Λ, as well as the value of an analogous term in an analogous gravity model in the form of a BEC. BECs are correctly described only by quantum models, and a quantum theory of gravity may be required to correctly predict Λ. Image credit: Finazzi, et al. ©2012 American Physical Society

(PhysOrg.com) -- Some scientists call the cosmological constant the "worst prediction of physics." And when today’s theories give an estimated value that is about 120 orders of magnitude larger than the measured value, it’s hard to argue with that title. In a new study, a team of physicists has taken a different view of the cosmological constant, Λ, which drives the accelerated expansion of the universe. While the cosmological constant is usually interpreted as a vacuum energy, here the physicists provide evidence to support the possibility that the mysterious force instead emerges from a microscopic quantum theory of gravity, which is currently beyond physicists’ reach.

The scientists, Stefano Finazzi, currently of the University of Trento in Povo-Trento, Italy; Stefano Liberati at SISSA, INFN in Trieste, Italy; and Lorenzo Sindoni from the Albert Einstein Institute in Golm, Germany, have published their study in a recent issue of .

The authors are far from the first who are dissatisfied with the . Previously, other scientists have suggested that the huge discrepancy between the observed and estimated values is due to the use of semi-classical effective field theory (EFT) calculations for estimating a quantity that can be computed only using a full of . Although no one can show what value a quantum theory of gravity would give without having such a theory, physicists have shown that EFT calculations fail at estimating similar values in analogue gravity models.

Here, the physicists consider an analogue gravity model in the form of a Bose-Einstein condensate (BEC), a group of atoms that behave as a single quantum system when cooled to temperatures near absolute zero. While a BEC may seem to have nothing in common with the expanding universe, the physicists showed in a previous paper that a BEC can be described by the same Poisson equation that describes nonrelativistic (Newtonian) gravity. This framework includes a term that is analogous to the cosmological constant; this term describes the part of a BEC’s ground-state energy that corresponds to the condensate’s quantum depletion.

Since BECs are accurately described by other (quantum) equations, the physicists decided to test how well EFT calculations could compute the BEC’s analogous cosmological constant term. They found that EFT calculations do not give the correct result. The finding confirms the earlier studies that showed that EFT calculations produce an incorrect result when used to compute the ground-state energy of other analogue gravity models.

“We have shown how conceptually subtle could be the computation of the cosmological constant, by considering an analogue gravity model,” Finazzi told PhysOrg.com. “This simple example shows that the knowledge of the microscopic structure of spacetime might be an essential guide for a correct interpretation of the nature of the cosmological constant, and hence for a correct estimate of it. We then reinterpret the large discrepancy between the naive computation and the observed value as a basic misunderstanding on this point. Interestingly, this reasoning might also be a guide to the selection of the correct quantum gravity theory.”

As the physicists explain, the BEC model described by Poisson equations is too simple to completely describe the complex features of the universe’s accelerating expansion. However, the failure of the EFT framework to describe BECs’ analogue cosmological constant supports the possibility that the EFT framework also fails at describing the cosmological constant.

The details have further implications. For one thing, the results suggest that there may be no a priori reason to describe the cosmological constant as vacuum energy. Instead, the cosmological constant may emerge from the underlying quantum theory of gravity describing spacetime. As the physicists explain, a quantum theory of gravity differs from various modified theories of gravity that have been proposed recently in that a quantum theory describes spacetime at the most fundamental level.

“In a modified gravity theory, one is just postulating a different gravitational dynamics that might show accelerated expansion also for a universe filled with standard matter (i.e., without the so-called dark energy component),” Liberati said. “We instead consider the case where a gravitational dynamics is emergent from a microscopic quantum theory, i.e., a theory describing the fundamental constituents, whatever they are, of our spacetime. From such a theory one would be able to derive a theory of gravity (general relativity or any form of modified gravity) in some appropriate limit (possibly similar in nature to the hydrodynamic limit of a gas of interacting atoms). Our point is that it is only throughout this derivation/emergence of the gravitational dynamics that in the end one can determine what is the gravitating ‘energy of the vacuum.’ We have proven this explicitly in our toy model where it is clearly shown that the use of the macroscopic constituents (and corresponding energy scales) of the emergent physics might lead to a completely wrong estimate.

“We can try to explain this issue with a simple analogy,” he said. “Water is made by molecules. At a microscopic level molecular dynamics is properly described by quantum mechanics. However, no one would use quantum mechanics to describe a flowing river, but rather one would use fluid mechanics laws. Of course, fluid dynamics must be compatible with quantum mechanics, i.e., it must be possible to derive it from the microscopic quantum theory of molecules. Finally, the choice of the most appropriate equations for the description of any phenomenon depends on the scale at which one observes the physical system. We hence can say that the microscopic quantum theory of gravity corresponds in the analogy to the quantum mechanics of molecules, a theory of gravity corresponds to fluid mechanics, and the evolution of the universe to the flow of the river.”

Continuing the analogy, Liberati adds that there might be a quantity in macroscopic fluid dynamics that cannot be calculated using macroscopic parameters alone. Instead, a microscopic model is necessary to calculate the correct value.

“We argue that, in the case of the calculation of the cosmological constant, this is exactly what happens: the reason of the ‘worst prediction of theoretical ’ might ultimately be due to the attempt to compute a quantity that is sensitive to the microphysics only in terms of macroscopic quantities,” he said.

In the future, the physicists hope to further investigate how the BEC analogue model of gravity could possibly lead to the development of a quantum theory of gravity, since many proposed theories of gravity have features in common with the new model.

“We believe that this model can help to change the way how people usually think about the cosmological constant,” Sindoni said. “In recent years, the idea that spacetime is a form of condensate is gaining momentum. Of course, to be able to get to theories as close as possible to general relativity, the microscopic models have to be considerably more complex than BECs. However, it can be conjectured that spacetime is the final outcome of a phase transition for a large number of suitable microscopic constituents, and that the determination of the resulting macroscopic dynamics might be essentially the same, at the conceptual level, of the determination of the dynamics of a BEC from the knowledge of effective molecular or atomic dynamics, near a phase transition. The translation of the language and ideas of BECs to quantum gravity models might be a key in the understanding of the physical content of the latter.”

Sindoni adds that the cosmological constant will provide a vital test of any proposed quantum theory of gravity.

“We think that the comparison of the observational value of the cosmological constant against its theoretical value, predicted by any theory of quantum gravity, can be a very good (if not the unique) test to validate such theories,” he said.

Explore further: New approach to form non-equilibrium structures

More information: Stefano Finazzi, et al. “Cosmological Constant: A Lesson from Bose-Einstein Condensates.” PRL 108, 071101 (2012). DOI: 10.1103/PhysRevLett.108.071101

4.5 /5 (41 votes)

Related Stories

Physicists propose test for loop quantum gravity

Jan 03, 2012

(PhysOrg.com) -- As a quantum theory of gravity, loop quantum gravity could potentially solve one of the biggest problems in physics: reconciling general relativity and quantum mechanics. But like all tentative ...

Physicists investigate lower dimensions of the universe

Mar 18, 2011

(PhysOrg.com) -- Several speculative theories in physics involve extra dimensions beyond our well-known four (which are broken down into three dimensions of space and one of time). Some theories have suggested 5, 10, 26, ...

Four reasons why the quantum vacuum may explain dark matter

Nov 28, 2011

(PhysOrg.com) -- Earlier this year, PhysOrg reported on a new idea that suggested that gravitational charges in the quantum vacuum could provide an alternative to dark matter. The idea rests on the hypothesis that particles ...

Recommended for you

First in-situ images of void collapse in explosives

13 hours ago

While creating the first-ever images of explosives using an x-ray free electron laser in California, Los Alamos researchers and collaborators demonstrated a crucial diagnostic for studying how voids affect ...

New approach to form non-equilibrium structures

Jul 24, 2014

Although most natural and synthetic processes prefer to settle into equilibrium—a state of unchanging balance without potential or energy—it is within the realm of non-equilibrium conditions where new possibilities lie. ...

Nike krypton laser achieves spot in Guinness World Records

Jul 24, 2014

A set of experiments conducted on the Nike krypton fluoride (KrF) laser at the U.S. Naval Research Laboratory (NRL) nearly five years ago has, at long last, earned the coveted Guinness World Records title for achieving "Highest ...

User comments : 152

Adjust slider to filter visible comments by rank

Display comments: newest first

TS1
2.7 / 5 (14) Mar 05, 2012
"In recent years, the idea that spacetime is a form of condensate is gaining momentum."

Isn't that ether again..?
dtyarbrough
1 / 5 (29) Mar 05, 2012
Scientists have so much trouble explaining the expansion because there is no expansion. The universe is simply becoming gradually more opaque to light. This is due to solar particles as the billions and billions of stars burn their fuel. The stars emit far more solar wind than is required to explain this. It is likely that the visible universe is shrinking.
The rate of increase is density to create this illusion is a factor of 75 parts per 30,856,775,810,000,000,000 each second. That works out to 23652/308567758100000 per year. The density would have doubled over 13.04 billion years if this rate were not changing. The rate is however increasing as old stars are burning faster than new stars are forming. The rate of expansion appears to be increasing.

At the current rate, the sun will appear to be 0.712 miles farther away in 100 years.(twice its current distance in 13 billion years).
dschlink
2.3 / 5 (3) Mar 05, 2012
40 years since I studied physics, but the author made his point understandable.
hkreuz
3.9 / 5 (13) Mar 05, 2012
Scientists have so much trouble explaining the expansion because there is no expansion. The universe is simply becoming gradually more opaque to light. This is due to solar particles as the billions and billions of stars burn their fuel. The stars emit far more solar wind than is required to explain this. It is likely that the visible universe is shrinking.
The rate of increase is density to create this illusion is a factor of 75 parts per 30,856,775,810,000,000,000 each second. That works out to 23652/308567758100000 per year. The density would have doubled over 13.04 billion years if this rate were not changing. The rate is however increasing as old stars are burning faster than new stars are forming. The rate of expansion appears to be increasing.

At the current rate, the sun will appear to be 0.712 miles farther away in 100 years.(twice its current distance in 13 billion years).


So i'm assuming this is taking into account Edwin Hubble didn't exist.
Mike_Massen
4.5 / 5 (16) Mar 05, 2012
@dtyarbrough
You havent heard of significant figures then or exponents ?
Where did those figures come from, can u show your working ?
Where does red shift place in your idea re those figures ?
What solar particles are you on about, other than protons (hydrogen) ?
What do you mean by "..more solar wind than is required.." - for what ?
At the beginning of the para you say there is no expansion then you say the expansion is increasing - can you explain this contradiction ?
Was the sun closer by ~0.712 miles 100 years ago ?
As the sun has no specific surface then how can one confirm aspects of your idea over such short comparative distances without knowing where the sun's center happens to be at the time ?
TabulaMentis
2.1 / 5 (9) Mar 05, 2012
From Article:
While the cosmological constant is usually interpreted as a vacuum energy, here the physicists provide evidence to support the possibility that the mysterious force instead emerges from a microscopic quantum theory of gravity, which is currently beyond physicists reach.
The gravity the physicists' are talking about is in the ultramicroscopic realm which is definitely way too small for us to see or use. It is good to see physicists are turning away from Einstein Gravity (gravitational waves) and are turning towards something that has great potential.
TabulaMentis
3 / 5 (2) Mar 05, 2012
From Article:
The details have further implications. For one thing, the results suggest that there may be no a priori reason to describe the cosmological constant as vacuum energy. Instead, the cosmological constant may emerge from the underlying quantum theory of gravity describing spacetime. As the physicists explain, a quantum theory of gravity differs from various modified theories of gravity that have been proposed recently in that a quantum theory describes spacetime at the most fundamental level.
Yes, spacetime fabric (dark energy) does contain gravity (the good stuff) although almost all, if not all, particles contain a certain degree of gravity.

However, it can be conjectured that spacetime is the final outcome of a phase transition for a large number of suitable microscopic constituents.
That statement is like frosting on a big juicy cake.
Anda
5 / 5 (8) Mar 05, 2012
"In recent years, the idea that spacetime is a form of condensate is gaining momentum."

Isn't that ether again..?


No.

In the other hand there's no valid quantum gravity theory to date.

Waiting for you "water ripples"
Kinedryl
1 / 5 (13) Mar 05, 2012
The cosmological constant controversy is easy to understand with water surface space-time analogy of AWT based on dense aether model. At the water surface can observe the reality with transverse waves in two perspectives: one deals with much larger objects, than the wavelength of CMBR noise (and the size of humans), you're always inside of observable reality, so we can call it an intrinsic perspective. This perspective corresponds the quantum mechanics.

The second perspective is used for observations of small object, which are always observed from outside. This perspective is therefore called extrinsic and it essentially corresponds the perspective of quantum mechanics. These perspectives cannot be mixed, they're separated with hundreds of extradimensions each other. Nevertheless it means, when you observe the water surface from intrinsic perspective, it appears like nondispersive environment, whereas from intrinsic perspective we are confronted with highly dispersive underwater.
Noumenon
4 / 5 (8) Mar 05, 2012
It is good to see physicists are turning away from Einstein Gravity (gravitational waves) and are turning towards something that has great potential.


Where did they say they're turning away from 'Einstein Gravity'?
Kinedryl
1.1 / 5 (10) Mar 05, 2012
The cosmological constant is related to the perceived density of environment, which affects the speed, in which the energy waves are spreading in it. From intrinsic perspective the water surface would appear like sparse, nondispersive environment, whereas from extrinsic perspective it will appear like dense dispersive environment full of Brownian noise. The energy density ratio essentially corresponds the cube root of the ratio of speed of waves at the water surface and underwater.

At the case of vacuum, which is behaving like extremely dense environment this ratio is more than one hundred orders of magnitude, which leads to so-called http://en.wikiped...strophe. This is how the deep difference in predictions of vacuum density calculated from quantum field and general relativity theories is called. The string theory uses a renormalization approach, so its prediction of cosmological constant differs from reality in forty orders of magnitude.
TabulaMentis
1 / 5 (3) Mar 05, 2012
Where did they say they're turning away from 'Einstein Gravity'?
Einstein Gravity works on a universal scale. Quantum gravity is in the ultramicroscopic realm.
Kinedryl
1 / 5 (14) Mar 05, 2012
..but the author made his point understandable...
The river analogy is the step in the right i.e. "aetheric" direction - nevertheless the AWT handles the water surface analogy of space-time in even much more straightforward way. In dense aether model the Universe appearance is really just an heavily expanded situation of waves spreading at the water surface, extrapolated into hyperdimensional perspective of nested foam, forming the space-time.

It essentially means, if some artefact exists at the water surface, it MUST somehow exist at the cosmic space too. The opposite direction unfortunately doesn't work, because the Universe is way more complex, than the water surface. But the duality of observational perspectives and the values of cosmological constants and vacuum density can be deduced from the water surface analogy in quite trivial way. You needn't to bother with boson condensates and with river flow, as these parables just obscure the geometry of the water surface analogy
Kinedryl
1 / 5 (12) Mar 05, 2012
My question therefore is, why various physicists don't use the water analogy in its most straightforward way? If nothing else, it would make the mainstream physics more palatable for normal people. The average physicists must know about it in the same way, like every reader of PO forum.

My suspicion is, the mainstream physics community avoids the using of all models, which would make the subject of their research more transparent for laymans. Many concepts of string theory or supersymmetry could be explained in much more straightforward way with it. But you can get these analogies only in close range of experts and they're generally considered a heretical.

Eduard Witten: "One thing I can tell you, though, is that most string theorists suspect that spacetime is a emergent phenomena in the language of condensed matter physics".

These guys know quite well about dense aether model. But they will not admit it.
dtyarbrough
1 / 5 (10) Mar 05, 2012
@dtyarbrough
You havent heard of significant figures then or exponents ?
Where did those figures come from, can u show your working ?
Where does red shift place in your idea re those figures ?
What solar particles are you on about, other than protons (hydrogen) ?
What do you mean by "..more solar wind than is required.." - for what ?
At the beginning of the para you say there is no expansion then you say the expansion is increasing - can you explain this contradiction ?
Was the sun closer by ~0.712 miles 100 years ago ?
As the sun has no specific surface then how can one confirm aspects of your idea over such short comparative distances without knowing where the sun's center happens to be at the time ?

There is only the appearance of an increasing expansion. The numbers are based on the hubble constant of 75Km/sec expansion over a distance of 30,856,775,810,000,000,000 km. Red shift occurs when the light passes through various densities(I think).
Kinedryl
1.2 / 5 (10) Mar 05, 2012
The universe is simply becoming gradually more opaque to light.
This is essentially correct insight. But wait...
This is due to solar particles as the billions and billions of stars burn their fuel.
This is suspicious claim and it sounds "crackpotish" for me. What the "fuel" is supposed to mean?
The stars emit far more solar wind than is required to explain this.
And this is unfortunately apparent BS already. The contemporary cosmology doesn't bother with solar wind at all, so it cannot face any excess of it. In addition, the speed in which light is losing its energy during travel trough vast areas of CMBR noise has nothing to do with intensity of solar wind at all. The intensity of solar wind has nothing to do with the speed of light dispersion (which propagates a way faster than the solar wind particles, BTW).
Kinedryl
1 / 5 (7) Mar 05, 2012
The conceptual thinking doesn't require some solar wind particles for explanation of light dispersion at all. In dense aether model the space-time simply must always remain inhomogeneous, or it couldn't exist at all. The water surface appears so large for surface waves, because these waves are spreading so slowly in it. These waves are slowed down with myriads of tiny density fluctuations, the gradient of which is serving as an environment for for surface wave spreading. The Brownian noise cannot be separated from space-time concept. And this noise is sufficient for explanation of the light dispersion by itself. We are observing it as a CMBR noise fifty years already.

The similar result follows from general relativity, in which the space-time must be always curved - or it couldn't exist at all. After all, this is the original reason, for which Einstein adjusted his theory with arbitrary constant - and it has lead to Friedman models developed later.
TabulaMentis
4.2 / 5 (5) Mar 05, 2012
Edward Witten: "One thing I can tell you, though, is that most string theorists suspect that spacetime is a emergent phenomena in the language of condensed matter physics".
Edward Witten also said people need to start thinking in eleven-dimensions and not in one and twos.
Kinedryl
1 / 5 (9) Mar 05, 2012
The another thing is, whereas the CMBR noise is essential for whole existence of space-time in general relativity, it violates the general relativity from more general perspective, being a source of dark matter and energy artefacts. Every tiny fluctuation follows the GR well at the local level - but in average their different density leads to the effects, which are inconsistent with GR at the global level. This animation illustrates it for gravitational lensing. Locally every fluctuation behaves as a tiny gravitational lens, fulfilling the general relativity laws well - the light is moving along geodesics with constant speed all the time. But the variable concentration of these curved paths is something, which general relativity cannot account to. So it becomes violated gradually and the speed of light changes from place to place. In Czech we have a proverb for it:"A hundred times nothing killed the donkey."
Kinedryl
1.4 / 5 (10) Mar 05, 2012
Edward Witten also said people need to start thinking in eleven-dimensions and not in one and twos.
And he was still correct because of it. In AWT these two approaches are dual, which is why it's called an AETHER WAVE theory: the nested density fluctuations of many particles in low number of dimensions correspond the spreading of low number of waves in high number of dimensions. These two approaches are essentially interchangeable, but the former one is still easier to grasp with human brain, which used to handle particle environment during whole human history.

There are few less or more straightforward ways, how to understand this duality. In general, the hyperdimensional object becomes the more fuzzy, random and separated spatially, the lower number of dimensions we are using for its observation. We could say, we are observing it's noncompact lowdimensional slice of it.
Kinedryl
1 / 5 (8) Mar 05, 2012
In essence, if we would compress the dense gas into small box, it's foamy density fluctuations would form the same seemingly random mess, like if we would solve the wave equation in lets say fifty dimensions and observed the three-dimensional projection of the resulting solution into this small box.
TabulaMentis
2 / 5 (4) Mar 05, 2012
but the former one is still easier to grasp with human brain, which used to handle particle environment during whole human history.
My brain works quite well when it come to math and physics. Edward Witten needs to explain how you can skip one and two to get to eleven.
Kinedryl
1 / 5 (9) Mar 05, 2012
Witten needs to explain how you can skip one and two to get to eleven.
String theory has explained it before years, but this explanation is not palatable for those, who don't understand the formal math very well. AWT provides more accessible explanation based on real life experience: no matter, how much the dense gas is compressed, its density fluctuations will always remain close to 3D spheres. Even when the another level of density fluctuations is formed, then the resulting nested hyperspheres are most close to 3D spheres in their shape. It's because this way of energy spreading is most effective with respect to principle of least action. The surface-radius ratio of hypersphere doesn't increase with increasing number of dimensions in monotonous way, but it gets through supremum just for 3D hyperspheres. It means, just the 3D particles and density fluctuations allows the most intensive propagation of energy at distance and such Universe would appear most dense and observable.
Kinedryl
1.6 / 5 (8) Mar 05, 2012
The string theory based derivation of space-time dimensionality you can find for example here
http://news.disco...19.html, but similar solutions have been provided before many years already. Because it's essentially invariant to the geometry of elements choosen, the same result provides the optimization of "entropy flow" for holographic projection by number of dimensions: http://arxiv.org/abs/1106.4548
TabulaMentis
3 / 5 (2) Mar 05, 2012
String theory has explained it before years, but this explanation is not palatable for those, who don't understand the formal math very well.
Like I said: "My brain works quite well when it come to math and physics." I am not a proponent of string theory (M-theory). And from the looks of it with your Dense Aether Theory you are not a string theory lover either.
jsdarkdestruction
5 / 5 (5) Mar 05, 2012
I'm disappointed. I was hoping for something more sunstansial than "It must be because of quantum gravity". I was expecting a breakthrough of some sort and very excited.
Kinedryl
1 / 5 (5) Mar 05, 2012
I am not a proponent of string theory (M-theory). And from the looks of it with your Dense Aether Theory you are not a string theory lover either

String theory is too schematic. IMO the same result could be achieved in much easier way with finding of speed of energy spreading with common wave equations in gradually increasing number of dimensions. Why nobody checked how the wave equation behaves in higher dimensional space? We are missing the simplest numeric experiments in this directions.
Torbjorn_Larsson_OM
5 / 5 (8) Mar 05, 2012
This corresponds well to the problem of predicting the total energy of the universe. General relativity has no such concept, it can hint at the right answer, but the real prediction (of zero energy) is emergent from a system analysis. (Faraoni et al.)

@ KinedryL: "The cosmological constant controversy is easy to understand with water surface space-time analogy of AWT based on dense aether model."

We have known since the early 20th century that there is no aether. No go; and please do keep up!
Cave_Man
1.8 / 5 (5) Mar 05, 2012
No offense but there has to be more than 11 dimensions:

Take a simple journey with me into conceptual space, try to imagine zero, the concept of it, try to imagine what zero really is. It's impossible to comprehend but we can say stuff like before the big bang or after the entire universe decays in a few quadrillion years etc etc. Some also equate zero with death and perfect stillness.

But since here we are in the universe which has stuff instead of nothing we start to progress conceptually, zero may be nothing but the funny part is that zero is a concept to us and therefore a thing. When examined it becomes a thing or ONE thing. Giving rise to the concept of one is interesting it sets up a more complex relationship of concepts ie zero and one.

Well now, if I take everything I have now, the concept of zero and the concept of one, well holy smokes that's two things. And as soon as you conceptualize two you now have three distinct concepts, zero, one and two.
Cave_Man
1 / 5 (2) Mar 05, 2012
So maybe now you can understand a little better how nothing led to an infinite. At least in terms of human understanding. I think this all has to do with simplex theory but I came up with it myself before i heard or saw any other examples.

I personally believe it is a big part of the meaning of the universe. In the same way we might draw interesting conclusions about the origins of consciousness or reality simply by studying other culture or employing hallucinogens.

Everything we do is adding another number to that chain of infinite quanta. Because if zero is "real" then every number you conceive of is really part of a system that is always exactly one higher than the current level.
julianpenrod
1 / 5 (6) Mar 05, 2012
The fact is, there is not acceleration of the expansion of the universe.
That is given as a "conclusion" from the "discovery" that "supernovas five billion light years away are receding faster than they should be". Up to five billion light years away, galaxies are receding according to Hubble's Law, but, at five billion light years, galaxies are moving away at a faster Hubble Constant. But galaxies closer to us, galaxies viewed at less than five billion years ago, are moving at the lower Hubble Constant! But that means that expansion occurring in the recent past is less than that of galaxies five billion years ago! And that means that expansion is less than that at five billion years ago, and that means the universe is not speeding up!
Callippo
1.7 / 5 (6) Mar 05, 2012
We have known since the early 20th century that there is no aether. No go; and please do keep up!
In recent years, the idea that spacetime is a form of condensate is gaining momentum. Of course, to be able to get to theories as close as possible to general relativity, the microscopic models have to be considerably more complex than BECs. However, it can be conjectured that spacetime is the final outcome of a phase transition for a large number of suitable microscopic constituents, and that the determination of the resulting macroscopic dynamics might be essentially the same, at the conceptual level, of the determination of the dynamics of a BEC from the knowledge of effective molecular or atomic dynamics, near a phase transition...
havasu
1 / 5 (4) Mar 05, 2012
"The fact is, there is not acceleration of the expansion of the universe."

We cannot determine if the universe is expanding or accelerating until we properly account for "red" shifting of light frequencies due to bending. Shifting until the light changes from visible specturm to radio spectrum and gets confused as the echo of the Big Bang.
bewertow
3.7 / 5 (3) Mar 05, 2012
I am not a proponent of string theory (M-theory). And from the looks of it with your Dense Aether Theory you are not a string theory lover either

String theory is too schematic. IMO the same result could be achieved in much easier way with finding of speed of energy spreading with common wave equations in gradually increasing number of dimensions. Why nobody checked how the wave equation behaves in higher dimensional space? We are missing the simplest numeric experiments in this directions.


Reported for spamming.

Also, you are clearly an idiot. The wave equation is just a Sturm-Liouville hyperbolic PDE. It's behaviour is already well-understood in arbitrary dimensions.

TabulaMentis
3.7 / 5 (3) Mar 05, 2012
Well now, if I take everything I have now, the concept of zero and the concept of one, well holy smokes that's two things. And as soon as you conceptualize two you now have three distinct concepts, zero, one and two.
A qutrit.
jsdarkdestruction
5 / 5 (1) Mar 05, 2012
I'm disappointed. I was hoping for something more sunstansial than "It must be because of quantum gravity". I was expecting a breakthrough of some sort and very excited.

substantial. sorry
Silverhill
5 / 5 (5) Mar 05, 2012
The universe is simply becoming gradually more opaque to light. This is due to solar particles as the billions and billions of stars burn their fuel.
The last time I checked, hydrogen and helium (by far the greatest fractions of the solar wind) were completely transparent to visible light. Neither has there been any (reliable) report to the contrary.
Tausch
1 / 5 (3) Mar 05, 2012
lol

"You are playing the wrong note!"
"Impossible! The 'score' says play any note(s)or no note here!"
"There's no recognizable rhythm, rhyme, continuity, consistence or melody!"

Physics...of music.
Urgelt
5 / 5 (8) Mar 05, 2012
The cranks are out in force today.

*checks moon phase*

Yep, full moon.
GuruShabu
1 / 5 (9) Mar 06, 2012
I will receive many "1s" but I will write what most of people don't like to hear/read.
The universe is NOT expanding, red-shift is NOT due to expansion but to photons loosing momentum due to encounters with electric charged particles, etc.
We need to stop pulling theories from our mind just because they are "beautiful"so they MUST be true...and last but not least: There was never a BigBang!
The universe is infinite.
Hopefully, the new space Webb Telescope will show that there are galaxies beyond 1e billion light-years that are complete, beautifully spirals, elliptical, whatever that could not have been formed before the BB.
jsdarkdestruction
4.4 / 5 (7) Mar 06, 2012
yeah, we dont like to hear it because its nonsense.
Kinedryl
1.4 / 5 (9) Mar 06, 2012
yeah, we dont like to hear it because its nonsense.
You just downoted him, so why are you using a plural majesticus? Are you infallible pope or something similar? Try to learn to speak for yourself.
Kinedryl
1.5 / 5 (8) Mar 06, 2012
Hopefully, the new space Webb Telescope will show that there are galaxies beyond 1e billion light-years that are complete, beautifully spirals, elliptical, whatever that could not have been formed before the BB.
IMO the JWST will never leave the Earth. It's heavily delayed, overpriced and its cameras have large number of pixels dysfunctional already - a five years before starting the mission.

http://savethiste...pot.com/
http://www.spacen...wst.html

Anyway, we have enough of evidence, that the universe is way larger, than the Big Bang theory allows - despite the opinion of famous PO trolls, who cannot swallow new facts. http://www.techno...iv/26333
bewertow
4.3 / 5 (6) Mar 06, 2012
Anyway, we have enough of evidence, that the universe is way larger, than the Big Bang theory allows - despite the opinion of famous PO trolls, who cannot swallow new facts. http://www.techno...iv/26333


Wow, you're an idiot. Did you even read the article you cited? Everyone already knows that the universe is bigger than the observable universe.

This just places a lower limit on the size of the universe if it is positively curved.

Wow, so many people here who think they're experts in cosmology just from browsing the web. If you were actually interested in cosmology, you would care enough to read a basic introduction on the subject.
Kinedryl
1 / 5 (6) Mar 06, 2012
Everyone already knows that the universe is bigger than the observable universe.
Of course, but by Big Bang theory the diameter of Universe can be 93 billion light years only - not 3425 billion light years. http://en.wikiped...rse#Size So it's just you, who is the personality above claimed and who cannot read the basic articles about subject... :-P I'm not sayin' "wow" though, because I'm not very surprised with it.
bewertow
5 / 5 (4) Mar 06, 2012
Everyone already knows that the universe is bigger than the observable universe.
Of course, but by Big Bang theory the diameter of Universe can be 93 billion light years only - not 3425 billion light years. http://en.wikiped...rse#Size So it's just you, who is the personality above claimed and who cannot read the basic articles about subject... :-P I'm not sayin' "wow" though, because I'm not very surprised with it.


No. You have no idea what you are talking about. The universe is INFINITE in every possible scenario except when omega>1. Go ahead and solve the Friedmann equation for a flat universe with the current best estimates of energy densities for the different components and it will be obvious. You are an uneducated fool with no background in cosmology.
Seeker2
1 / 5 (1) Mar 06, 2012
"Of course, to be able to get to theories as close as possible to general relativity, the microscopic models have to be considerably more complex than BECs."

Note Lorentz contraction, time dilation, and mass increase can be easily explained using a very simple quantum model of spacetime - hollow shells of energy carried on the surface, with propagation along this surface. A 2d cut of one of these quanta would be a circle with diameter ab, for instance. The propagation occurs on the circumference of the circle but the distance which the quantum travels would be the distance ab. Applied force (for example gravity) causes the circle to collapse so the distance ab becomes smaller. That is the distance which the quantum travels in the time it takes to propagate around the perimeter becomes smaller, but the distance around the perimeter remains constant. So the quantum appears to slow down.
Kinedryl
1.9 / 5 (9) Mar 06, 2012
No. You have no idea what you are talking about. The universe is INFINITE in every possible scenario except when omega>1
I don't believe you. You should rewrite the corresponding section at Wikipedia first - or you should consult the list of common miconceptions here http://en.wikiped...ceptions The infinite size of Universe is valid only for Universe of infinite age in Friedman models (which you apparently don't understand at all). Anyway, the Wikipedia says clearly, how large the Universe is predicted with Big Bang theory. You're not a relevant source of information for me. You should rewrite its record first, or I will simply not discuss it with you here.
You are an uneducated fool with no background in cosmology.
And you're a victim of Dunning-Krueger effect. You're so silly, you even cannot recognize, who is actually clever here and who not.
Seeker2
1 / 5 (2) Mar 06, 2012
cont...
The area of the circle is reduced as the quantum is compressed, so the energy density (mass) of the quantum is increased. Finally if an infinite force is applied to the quantum its area goes to zero and its mass density goes to infinity. So in this model mass is the actual energy density of spacetime quanta. The spacetime quanta of matter take many different forms but its mass depends only on the density of these quanta.
Kinedryl
1 / 5 (5) Mar 06, 2012
The area of the circle is reduced as the quantum is compressed
A quantum? The "quantum" means nothing, so it cannot be compressed. It has no volume defined.
Seeker2
3 / 5 (2) Mar 06, 2012
The area of the circle is reduced as the quantum is compressed
A quantum? The "quantum" means nothing, so it cannot be compressed. It has no volume defined.
Try for example one planck volume of spacetime.
Kinedryl
1 / 5 (5) Mar 06, 2012
Try for example one planck volume of spacetime.
I'm not obliged to check anything. This is not a "quantum". This is a "Planck volume", i.e. not a "quantum" and it's invariant until the Planck constant remains constant. Do you realize, how mentally incoherent your posts actually are? You're using the words and concepts of mainstream physics outside the scope of their meaning. If the "quantum" can "expand", then everything is actually possible: the "space-time" can "jump" or the "energy" can "sink" or whatever else.
Fleetfoot
5 / 5 (5) Mar 06, 2012
The universe is NOT expanding, red-shift is NOT due to expansion but to photons loosing momentum due to encounters with electric charged particles, etc.


Such interactions produce effects that are frequency dependent:

http://astronomy....0Measure

Cosmological redshift is independent of frequency. In 1985, Wolfe et al studied light from quasar PKS0458-02. The quasar itself is at z=2.29 but the light from it passes through a gas cloud at z=2.039. The Lyman alpha line and the 21cm line have the same redshift to within 0.03% even though the frequencies differ by a factor of over 172,000:

http://books.goog...;f=false

In addition, distant supernova light curves last longer because the distance between us and the source increases during the time we can watch them so expansion is proven beyond doubt. Deal with it.
Kinedryl
1 / 5 (5) Mar 06, 2012
Such interactions produce effects that are frequency dependent
In dense aether model the light is indeed not slowed down with particles of solar wind (which are of short distance scope and they do interact with charged bodies only) - but with omnipresent density fluctuations of vacuum, which are manifesting itself as a CMBR photons. This effect is indeed frequency dependent. For example, the CMBR photons cannot disperse with itself, which means, at the wavelength of CMBR all red shift effects will effectively disappear from Universe and the Universe will appear rock steady state at this wavelength. This prediction of aether model has been confirmed many times already. In addition, from AWT follows, for light of longer wavelength the red shift effects will be reversed and the Universe will appear collapsing. Again, we have observational evidence of these effects.
Seeker2
1 / 5 (1) Mar 06, 2012
Try for example one planck volume of spacetime.
I'm not obliged to check anything. This is not a "quantum". This is a "Planck volume", i.e. not a "quantum" and it's invariant until the Planck constant remains constant. Do you realize, how mentally incoherent your posts actually are? You're using the words and concepts of mainstream physics outside the scope of their meaning. If the "quantum" can "expand", then everything is actually possible: the "space-time" can "jump" or the "energy" can "sink" or whatever else.
You're right. I certainly wouldn't say the quantum can expand.
Kinedryl
1 / 5 (4) Mar 06, 2012
The fluctuations which would be able to disperse the light under shifting of its frequency must be very thin and sparse, so that the light wave can actually travel trough it without changing its direction. Only the quantum fluctuations of vacuum have such a properties. The charged particles disperse the light with Compton scattering, which changes the direction of light and such a light is effectively wasted for terrestrial observer. In addition, the effective crossection of such interaction is very low, because solar wind is very sparse in comparison to photon flux from stars. We would always have two portions of light: scattered with frequency shifted with distance and non-scattered one, which wouldn't depend on the distance. It would mean, we wouldn't see the spectral lines of elements, but the spectral bands in the light of distant galaxies together.
You're right. I certainly wouldn't say the quantum can expand.
After then it cannot be compressed. Problem solved.
Seeker2
4 / 5 (4) Mar 06, 2012
After then it cannot be compressed. Problem solved.
Unless you compress it into some form of matter, or otherwise apply a force such as gravity, as in the model proposed.
dtyarbrough
1 / 5 (2) Mar 06, 2012
I believe that the purpose of these comments should be to bring forth new ideas preferably as they pertain to the article. If the ideas are new then at least 95% of accredited scientists will disagree. Your personal opinions of someone elses ideas are of no importance. We don't need you to protect us from radical ideas. Express your own idea and be done. This is aimed at no one in particular. Sorry this doesn't pertain to this specific article.
Fleetfoot
5 / 5 (8) Mar 06, 2012
Such interactions produce effects that are frequency dependent
In dense aether model ...


There is no "dense aether model", a gaseous or liquid model cannot support transverse waves as I explained to you four days ago in this thread:

http://www.physor...um-.html
Fleetfoot
5 / 5 (8) Mar 06, 2012
I believe that the purpose of these comments should be to bring forth new ideas preferably as they pertain to the article. If the ideas are new then at least 95% of accredited scientists will disagree.


That is because the posters here generally have limited knowledge of the current state of observational evidence. For example one poster has suggested that cosmological redshift might be due to particle interactions. He was obviously unaware of the use of that effect in measuring electron densities in the light path of pulsars and the widely known fact that cosmological redshift is frequency independent.

No purpose is served by people spending their time posting ideas that are not viable due to their ignorance of what we already know. For example, my posting the link to the measurements made by Wolfe et al. doesn't stop anyone thinking about the topic, but it does give them another data point that any workable theory must match.
bewertow
5 / 5 (5) Mar 06, 2012
No. You have no idea what you are talking about. The universe is INFINITE in every possible scenario except when omega>1
I don't believe you. You should rewrite the corresponding section at Wikipedia first - or you should consult the list of common miconceptions here http://en.wikiped...eptions. You're so silly, you even cannot recognize, who is actually clever here and who not.


You are so incredibly arrogant it's shocking. You don't even understand the Dunning-Kruger effect which you're referring to. The effect refers to the phenomenon where incompetent people (such as yourself) are too incompetent to realize why they are wrong.

I actually know what I'm talking about. I've taken courses in cosmology in astrophysics and I have personally solved the Friedmann equation more times than I can count.

I will repeat again since you can't grasp it. The observable universe is NOT the same as the size of the actual universe!
Fleetfoot
5 / 5 (7) Mar 06, 2012
This just places a lower limit on the size of the universe if it is positively curved.

Wow, so many people here who think they're experts in cosmology just from browsing the web. If you were actually interested in cosmology, you would care enough to read a basic introduction on the subject.


"Bewertow" is correct, the "concordance model" which is the best fit to what we know is as close to flat as we can measure implying that it is either infinite or at least much bigger than the tiny patch we can observe. If anyone wants to learn a bit about the current models, this is probably the most cited tutorial around and reasonably accessible for anyone with some basic physics background:

http://www.astro....o_01.htm

For those who want to dispute the model, finding out what it says rather than tilting at windmills is probably a good idea too ;-)
bewertow
5 / 5 (3) Mar 06, 2012
I don't believe you. You should rewrite the corresponding section at Wikipedia first


Solve the Friedmann equation yourself if you don't believe me. Even if you consider a simplified two-component model (which is trivial to solve) then you can easily see what is going on.

If you can't even solve a simple ODE for yourself, then your opinions are clearly meaningless and irrelevant.
Kinedryl
1 / 5 (4) Mar 06, 2012
No Friedmann model predicts infinite size for finite age Universe. Period.

http://www.phys-a...dels.jpg
bewertow
5 / 5 (5) Mar 06, 2012
No Friedmann model predicts infinite size for finite age Universe. Period.

http://www.phys-a...dels.jpg


Oh really? So you took my advice and solved the Friedmann equation and proved it?

Oh right, I forgot, you are too incompetent to even solve a simple ODE!

I will repeat again since you are so incredibly stupid: THE ONLY CASE WHERE THE UNIVERSE IS FINITE IN SIZE IS FOR OMEGA>1. There is no arguing with this. This is literally the first or second chapter in any introductory cosmology book. Get your fat ass to the library and check out a book if you don't believe me.
bewertow
5 / 5 (5) Mar 06, 2012
No Friedmann model predicts infinite size for finite age Universe. Period.

http://www.phys-a...dels.jpg


You don't even understand the diagram you linked to.

The separation between galaxies is NOT the same as the size of the universe. The separation between galaxies is determined by the scale factor.

Seriously, you don't even understand the most basic principles of cosmology, astrophysics or GR.
Kinedryl
1 / 5 (6) Mar 06, 2012
THE ONLY CASE WHERE THE UNIVERSE IS FINITE IN SIZE IS FOR OMEGA >1
LOL... :-) http://www.physic...odel.gif It's evident, you're shouting about universe of infinite age, not about the Big Bang universe, which is just 13.7 GYrs old. These mathematicians and ODE solvers.. Do you see? They will remain silly 4ever.....;-)
Fleetfoot
5 / 5 (6) Mar 06, 2012
No Friedmann model predicts infinite size for finite age Universe. Period.

http://www.phys-a...dels.jpg


The word "open" means infinite.

http://www.physic...odel.gif


Like cometary orbits, the "flat" and "hyperbolic" cases are infinite, only the "hypershpherical" case is finite. The volume of the universe is then like the surface of a sphere, finite but without a boundary.

It's evident, you're shouting about universe of infinite age, not about the Big Bang universe, which is just 13.7 GYrs old.


Nope, he's teaching you cosmology 101.
bewertow
5 / 5 (5) Mar 06, 2012
THE ONLY CASE WHERE THE UNIVERSE IS FINITE IN SIZE IS FOR OMEGA >1
LOL... :-) http://www.physic...odel.gif It's evident, you're shouting about universe of infinite age, not about the Big Bang universe, which is just 13.7 GYrs old. These mathematicians and ODE solvers.. Do you see? They will remain silly 4ever.....;-)


I can't tell if you're just trolling, or if you are actually this incredibly stupid.

You keep linking to the same diagram. Scale factor is NOT the same as the size of the universe. I have been repeatedly telling you this over and over but you can't get it through your head.

The parameter which determines whether the universe is finite or infinite is the curvature constant. Hyperbolic and flat universes are ALWAYS INFINITE. We live in a flat, and therefore infinite universe.

Unlike you I actually have a degree in physics. I have studied cosmology. I know what I'm talking about.
Fleetfoot
5 / 5 (6) Mar 06, 2012
http://www.astro....o_03.htm

"Also remember that the o = 1 spacetime is infinite in extent so the conformal space-time diagram can go on far beyond our past lightcone, ..."

Prof. Wright's background:

http://www.astro....tro.html
Fleetfoot
5 / 5 (5) Mar 06, 2012
The parameter which determines whether the universe is finite or infinite is the curvature constant. Hyperbolic and flat universes are ALWAYS INFINITE. We live in a flat, and therefore infinite universe.


We can't be entirely sure of that though, inflation pushes curvature so close to flat that it could be just one side or the other and the difference would be immeasurable. Dark energy of course ensures there won't be a crunch either way so it's still uncertain if the universe is infinite or merely vastly larger than our small observable portion.

There is a fundamental difference in philosophical terms between the two but pragmatically they are indistinguishable.
Callippo
1 / 5 (6) Mar 06, 2012
The word "open" means infinite.... Unlike you I actually have a degree in physics. I have studied cosmology. I know what I'm talking about.
LOL, exactly as I expected...:-) Can you please depict on this diagram the actual size/scale factor of Universe by contemporary Big Bang cosmology? Just draw the segment of a line, label it and link back to this forum.
Callippo
1 / 5 (6) Mar 06, 2012
inflation pushes curvature so close to flat that it could be just one side or the other and the difference would be immeasurable
You apparently didn't understand the Big Bang cosmology, in which the Universe emerged from sub-Planckian singularity and it's of finite age. Such universe may be flat or not (it's completely irrelevant in this particular context) - but it will always remain of finite size, simply because the limited singularity cannot expand into infinity in limited time.

BTW It's just me and GuruShabu, who has been opposed here with opinion, the Universe is infinite. Now you're trying to convince us about the very same obstinately...;-)
Seeker2
1 / 5 (1) Mar 06, 2012
The string theory based derivation of space-time dimensionality you can find for example here
http://news.disco...19.html,
No luck.
Callippo
1 / 5 (2) Mar 06, 2012
Remove the comma at the end of link
http://news.disco...119.html
and it will work for you. Be careful what you click, as it can save a lotta troubles for you.
Tausch
1 / 5 (3) Mar 06, 2012
So a candidate for stratification is constant curvature?
When language falls short of describing observations...
everyone takes sides.
Fleetfoot
5 / 5 (3) Mar 07, 2012
The word "open" means infinite...
LOL, exactly as I expected...:-) Can you please depict on http://www.physic...odel.gif the actual size/scale factor of Universe by contemporary Big Bang cosmology? Just draw the segment of a line, label it and link back to this forum.


What you ask for is already on the diagram. The line marked "Omega=1 flat" is where WMAP etc. put us (though it should curve up to the right), and it is also the boundary between finite and infinite. Above or on that line, the universe is spatially infinite while below it space is finite but unbounded.

You don't appear to understand what the term "scale factor" means. It is a fractional change comparing distances between widely separated objects at different times. By convention, it has the value 1 at the present time. On its own it doesn't define the overall size. This is basic stuff, check any textbook on the subject.
Kinedryl
1 / 5 (4) Mar 07, 2012
@Fleefoot: OK, so do you agree, that the Universe is always infinite in Friedmann models and in Big Bag cosmology it's always finite, which makes these two models mutually incompatible?
Fleetfoot
5 / 5 (3) Mar 07, 2012
@Fleefoot: OK, so do you agree, that the Universe is always infinite in Friedmann models and in Big Bag cosmology it's always finite, which makes these two models mutually incompatible?


No. When Fred Hoyle coined the name "Big Bang model", he was talking of the expanding, finite age solution to the Friedmann Equations, they are one and the same.

Ignoring dark energy for a moment, the maths is simple. If the density of the universe was greater than a critical value, expansion would stop and reverse resulting in a "Big Crunch". That universe is also spatially of finite volume but unbounded, like the area of the surface of a sphere.

If the density is less than or equal to the critical value, the expansion would continue forever but would always be slowing like a bullet fired from the Earth at greater than escape velocity. That universe would be spatially infinite.

Observations say that the universe is probably flat:

http://map.gsfc.n...ape.html
Messori
1 / 5 (1) Mar 07, 2012
The twentieth century was the century of major scientific revolutions, triggered by Quantum Mechanics (which profoundly changed what we know about matter) and of Einstein's General Theory of Relativity (which radically changed what we know about time and space), in addition to a growing interest in the study of nonlinear dynamic systems (which changed what we know of the dynamics of physical phenomena). The question is: do we have a reference paradigm that properly integrates these three descriptions of the three fundamental aspects of reality, matter-energy, space-time, dynamic? So welcome to any effort that goes in this direction.
Kinedryl
1 / 5 (3) Mar 07, 2012
When Fred Hoyle coined the name "Big Bang model", he was talking of the expanding, finite age solution to the Friedmann Equations, they are one and the same.
I don't care, what some Fred Hoyle twaddled about before fifty years - my question is related to Big Bang theory, as it's accepted TODAY. In this theory (no-matter, whether it's called the L-CDM or FRLW model today) the Universe started its existence before 13,7 billions of years so it's of FINITE age. The flat Universe in Friedman's model for omega = 1 is INFINITE. Can you spot this difference?
Fleetfoot
5 / 5 (3) Mar 07, 2012
When Fred Hoyle coined the name "Big Bang model", he was talking of the expanding, finite age solution to the Friedmann Equations, they are one and the same.
I don't care, what some Fred Hoyle twaddled about before fifty years


Obviously, but if you learned a little about the subject before making wild statements, you wouldn't make so many errors.

my question is related to Big Bang theory, as it's accepted TODAY. In this theory (no-matter, whether it's called the L-CDM or FRLW model today) the Universe started its existence before 13,7 billions of years so it's of FINITE age. The flat Universe in Friedman's model for omega = 1 is INFINITE. Can you spot this difference?


For omega <= 1, the model says that spatial slices are and always have been of infinite extent.

The question is can you understand the difference between "age" and "spatial extent"?
Kinedryl
1 / 5 (4) Mar 07, 2012
The question is can you understand the difference between "age" and "spatial extent"?
If you said, the universe is flat and of infinite spatial extent in Friedman model (which is part of Standard model of cosmology), then this universe cannot be of finite age. In addition, the Friedman model apparently describes neither the initial explosion from singularity, neither inflation, which had come later.

Anyway, the whole formal model is pretty bothering for me, it just extrapolates the Universe formation with relativity (in pretty inconsistent way) - but it doesn't explain, what really happened with it, why it exploded, why it inflated, why it's expanding with accelerating speed. The contemporary cosmology is just a chain of formal regressions glued and fitted to observations. And because it lacks the sense, it remains ad-hoced.
Fleetfoot
5 / 5 (5) Mar 07, 2012
The question is can you understand the difference between "age" and "spatial extent"?
If you said, the universe is flat and of infinite spatial extent in Friedman model (which is part of Standard model of cosmology), then this universe cannot be of finite age. ...

http://www.physic...odel.gif


You need to think before posting, the curves in that plot all reach a scale factor of zero at a finite time in the past, that is the basic Big Bang model. What did you think it showed?

Anyway, the whole formal model is pretty bothering for me, it just extrapolates the Universe formation with relativity .. but it doesn't explain, what really happened with it


We live a long time after that event and the universe was opaque for the first 378 thousand years. In the absence of a QM model, extrapolating from what we can see is the best we can do.
Callippo
1 / 5 (4) Mar 07, 2012
the curves in that plot all reach a scale factor of zero at a finite time in the past
Well exactly - the Universe was of zero size at the very beginning, so it cannot be infinite at the 13,7 Gyrs time by the same model, despite the actual omega value.
Fleetfoot
5 / 5 (5) Mar 07, 2012
the curves in that plot all reach a scale factor of zero at a finite time in the past
Well exactly - the Universe was of zero size at the very beginning, so it cannot be infinite at the 13,7 Gyrs time by the same model, despite the actual omega value.


Zero scale factor times infinite extent doesn't give zero size, the product is undefined. That's the trouble with singularities.

To be more realistic, the Friedmann Equations are classical so they don't take account of QM effects. They can't tell us how that first event occurred or whether it resulted in a universe that is finite or infinite, only that it happened 13.7 billion years ago.
Callippo
1 / 5 (4) Mar 07, 2012
Zero scale factor times infinite extent doesn't give zero size
Once again: the extent handled with Friedmann equations applies to observable Universe, which is not infinite by now, at the 13.7 GYrs after Big Bang. So it can be infinite neither at the "zero time", when the Universe was supposed to be a way smaller.
Fleetfoot
5 / 5 (4) Mar 07, 2012
Zero scale factor times infinite extent doesn't give zero size
Once again: the extent handled with Friedmann equations applies to observable Universe, ...


No, the Friedmann Equations can be derived from the postulate that the universe is homogenous and isotropic (as shown by Robertson and Walker) so if they apply anywhere, they apply everywhere. Unfortunately there is no easy way to determine whether the universe is finite or infinite.
Callippo
1 / 5 (4) Mar 07, 2012
Unfortunately there is no easy way to determine whether the universe is finite or infinite.
You cannot have infinite space-time of finite age in relativity neither Big Bang theory. Observable Universe is definitely finite by observations and from these observation the finite age and Big Bang model were deduced. Friedman equations were derived from observable data, so they do apply to the observable Universe as well.

Here are another connections, which don't apply directly from the above Friedman model logic, but they're relevant to Big Bang model as well. For example, well known argument for finite Universe is Olber's paradox. It's believed, the light of distant objects are hidden with reionization epoch (dark ages), so they're unobservable. In Big Bang theory this epoch covers the particle horizon of Universe, thus placing strict limit for not only observable Universe size, but for the size of the whole Universe.
Callippo
1 / 5 (4) Mar 07, 2012
If the Universe would be really infinite, then we shouldn't observe the older epochs of Universe formation, because the particle horizon would be enough to cover them before our eyes. Just the fact, the Universe expands faster, than the speed of light behind the Hubble deep field would be sufficient to hide all older objects. But Big Bang theory considers, that the Universe is of finite age and it puts the origin of Universe right before the particle event horizon, because the density of observable Universe at this place reaches the GUT scale limit.

So, maybe it's easy determine whether the universe is finite or infinite, maybe not - but Big Bang theory rather clearly implies the finite size of Universe, which doesn't differ very much from observable Universe size. It can be ten times larger at best.
Fleetfoot
5 / 5 (4) Mar 08, 2012
You cannot have infinite space-time of finite age in relativity neither Big Bang theory.


On the contrary, for omega <= 1, that is the model that GR produces.

Observable Universe is definitely finite by observations and from these observation the finite age and Big Bang model were deduced. Friedman equations were derived from observable data, ..


That is wrong again, Friedmann published the equations as a purely theoretical solution to GR in 1922.

http://en.wikiped...lativity

Hubble found the first Cepheid variable in the Andromeda Galaxy in 1923 proving that it wasn't just a gas cloud in our own galaxy as Shapley was arguing. Bear in mind the Great Debate was only 2 years before Friedmann published his solution.

http://apod.nasa....e20.html

Fleetfoot
5 / 5 (5) Mar 08, 2012
If the Universe would be really infinite, then we shouldn't observe the older epochs of Universe formation, because the particle horizon would be enough to cover them before our eyes.


We can observe that epoch for "nearby" material, stuff from which light has taken nearly 13.7 billion years to reach us, but there is more stuff farther away that we can't see, and never will.

Just the fact, the Universe expands faster, than the speed of light behind the Hubble deep field would be sufficient to hide all older objects.


That's another common misconception. The HDF includes galaxies up to a redshift of 6 while. The distance between us and galaxies at a redshift of about 1 was increasing by about 1 light year per year. That's one reason why you cannot use a model with galaxies moving through space and redshift caused by Doppler shift, you have to use GR and the model of expanding space.
Kinedryl
1 / 5 (4) Mar 08, 2012
one reason why you cannot use a model with galaxies moving through space and redshift caused by Doppler shift
This is completely irrelevant to my objection. I know, the Friedman equations are based on general relativity and they don't provide the prediction of actual Universe size. This size is defined with another constrains of L-CDM model, with critical Universe density in particular. In pure GR model described with FLRW metric the most distant objects would disappear from sky due their red shift. In Big Bang theory they do disappear because of dark epoch of reionization way sooner.

Whereas in steady state Universe model the galaxies don't move at all and the space-time doesn't expand. The light is propagating with increasing speed while dispersing itself. This is why the more distant galaxies appear relatively larger than these close ones, whereas in GR they should collapse with condensing space-time accordingly.
Fleetfoot
5 / 5 (4) Mar 08, 2012
This is completely irrelevant to my objection.


Of course it's relevant, you were claiming we couldn't see older objects if expansion between us exceeded the speed of light and that's simply not true. You have so many misconceptions about the model that your objections don't even make sense.

I know, the Friedman equations are based on general relativity and they don't provide the prediction of actual Universe size. This size is defined with another constrains of L-CDM model, with critical Universe density in particular.


Nope, the density determines curvature and whether it is open or closed but not the size.

In pure GR model described with FLRW metric the most distant objects would disappear from sky due their red shift. In Big Bang theory they do disappear because of dark epoch of reionization way sooner.


Reionisation ended around z=6 (Gunn Peterson trough). The first stars are estimated at around z=65. We can see the CMBR at z=1089. Try again.
CardacianNeverid
4.5 / 5 (8) Mar 08, 2012
They can't tell us how that first event occurred or whether it resulted in a universe that is finite or infinite, only that it happened 13.7 billion years ago -Fleetfoot

Indeed. I don't know which notion boggles the mind more - that the universe is infinite or that it has a finite limit.
Benni
2 / 5 (4) Mar 08, 2012
Seriously, you don't even understand the most basic principles of cosmology, astrophysics or GR.

If we are to have in the Universe an average density of matter which differs from zero, however small may be that difference, then the Universe cannot be quasi-Euclidean. On the contrary, the results of calculation indicate that if matter be distributed uniformy, the Universe would necessarily be spherical (or elliptical). Since in reality the detailed distribution of matter is not uniform, the real universe will deviate in individual parts from the spherical, but it will be necessarily finite. In fact the theory supplies us with a simple connection between the space-expanse of the universe & the average density of matter in it.

Albert Einstein:Relativity-Section 30
Written: 1916 (revised edition 1924)
Part III: Considerations on the Universe as a Whole

"The Structure of Space According to the General Theory of Relativity"

Fleetfoot
5 / 5 (4) Mar 08, 2012
Seriously, you don't even understand the most basic principles of cosmology, astrophysics or GR. ...


This is from the WMAP site but it is a standard result you will find in most textbooks:

"The density of the universe also determines its geometry. If the density of the universe exceeds the critical density, then the geometry of space is closed and positively curved like the surface of a sphere. .. If the density of the universe is less than the critical density, then the geometry of space is open (infinite), and negatively curved like the surface of a saddle. If the density of the universe exactly equals the critical density, then the geometry of the universe is flat like a sheet of paper, and infinite in extent.

We now know that the universe is flat with only a 0.5% margin of error. This suggests that the Universe is infinite in extent; however, since the Universe has a finite age, we can only observe a finite volume of the Universe."
Fleetfoot
5 / 5 (2) Mar 08, 2012
This is from the WMAP site but it is a standard result you will find in most textbooks:


The link wouldn't fit into the character limit, it is:

http://map.gsfc.n...ape.html
Seeker2
1 / 5 (1) Mar 08, 2012
"Of course, to be able to get to theories as close as possible to general relativity, the microscopic models have to be considerably more complex than BECs."

Not according to my posts which were censored yesterday.
Seeker2
1 / 5 (2) Mar 08, 2012
"In recent years, the idea that spacetime is a form of condensate is gaining momentum."

Isn't that ether again..?
I think they're talking about a condensate of energy. Spacetime itself is more like a void, it only contains energy. Spacetime doesn't expand, only the distribution of energy within.
Callippo
1 / 5 (4) Mar 08, 2012
I think they're talking about a condensate of energy
Condensate of energy has no shape and geometry, so you can deduce nothing from such concept. In addition, it was never observed - we observed only some kind of photon condensation inside of dense environment, where the photons gain positive rest mass. Of course, such condensate is still better model of vacuum with respect to aether theory, than nothing - but this concept is fairly old already. Apparently, mainstream physics converges to the dense aether model again.
Benni
1 / 5 (2) Mar 08, 2012

We now know that the universe is flat with only a 0.5% margin of error. This suggests that the Universe is infinite in extent; however, since the Universe has a finite age, we can only observe a finite volume of the Universe."


What we know is that it's flat for as far as present instrumentation imposes measurement limits to reach further into the Universe. If the Universe is a lot bigger than is present consensus among cosmologists, and I mean like hundreds or thousands of times bigger, that creates odds in Einstein's favor that the Universe is "spherical & closed".
Callippo
1 / 5 (5) Mar 08, 2012
We now know that the universe is flat with only a 0.5% margin of error
We know, the Universe expands with accelerating speed, so it cannot be flat (if somebody claims the opposite, then the last Nobel price should be returned). In addition, even if the Universe is flat, the limited speed of light implies rather strict limit for the Universe size, which may be only 250x larger, than the observable Universe size.

http://arxiv.org/abs/1101.5476

Everything else is a speculation, which doesn't follow from L-CDM model, but some other private cosmology, which is inconsistent with it.
Callippo
1 / 5 (5) Mar 08, 2012
After finding of red shift Hubble wrote six years later:
"The velocity-distance relation is linear, the distribution of the nebula is uniform, there is no evidence of expansion, no trace of curvature, no restriction of the time scale and we find ourselves in the presence.... If redshifts are velocity shifts which measure the rate of expansion, the expanding models are definitely inconsistent with the observations that have been made, i.e. expanding models are a forced interpretation of the observational results. If the redshifts are a Doppler shift, then observations as they stand lead to the anomaly of a closed universe, curiously small and dense, and, it may be added, suspiciously young. On the other hand, if redshifts are not Doppler effects, these anomalies disappear and the region observed appears as a small, homogeneous, but insignificant portion of a universe extended indefinitely both in space and time."
daywalk3r
3.7 / 5 (9) Mar 08, 2012
I would normally not nitpick as there is lots of dirty laundry flying around in the comments sections (with most of it not even being worth the few atoms it occupies for storage), but after reading a few of the last posts by Fleetfoot feat. Teh Infamous Zephyr (aka Callipoo, aka Kynedril, aka..) I just couldn't help it but quote this little bit..

This suggests that the Universe is infinite in extent; however, since the Universe has a finite age, we can only observe a finite volume of the Universe.

Well, it's all nice that you point out the errors of others, try to teach them proper physics, and free them from their (obvious) "misconceptions"..

But do you ever try to fully comprehend what you write yourself?

For starters - many of your arguments were about a model which is based on GR. But regardless of that, you managed to butcher one of the most fundamental tenets of relativity just within the above quoted single sentence..

cont..
daywalk3r
3.5 / 5 (8) Mar 08, 2012
cont..
The tenet being, that SPACE and TIME are ONE entity.

There is no such thing as space without time (and vice-versa), up to a point where one could even say that space is an emergent property of time.

My point being, that you simply can NOT suggest infinite space WITHOUT infinite time to support it (as you did in the above quoted sentence).

The fact that you can divide and multiply zeroes/infinites on paper does not imply that it has any ressemblance to reality whatsoever.

Maybe I am being too picky here and you just used slightly wrong words to make youself clear..

Seeing as you are baseing it on Omega, perhaps "no limit" (from intrinsic perspective) would have been more fitting than "infinite extent" in this case?

cont..
daywalk3r
2.6 / 5 (5) Mar 08, 2012
cont..
I explain..

[Omega > 1] - would basicaly represent a black hole from the INSIDE perspective. Being seemingly infinitesimaly large when observed from the inside (due to full 4pi curvature), but seemingly infinitesimaly small when observed from the outside (being bellow the SS radius).

[Omega = 1] - could be called "Schwarzshild unity" in the BH slang :-)

[Omega < 1] - is where my brain refuses to cooperate, but suggests that we are part of an (ever faster) expanding "explosion", as is depicted by the BB model.

So yes, for [Omega > 1], from the "inside" perspective, you can move towards the "edge" but never be able to reach it, giving an impression of infinite freedom (eg. infinite extent), but this is just an illusion, as essentially you would be "moving in circles" at some point.

This is not the same as "infinite extent", as is clearly demonstrated by the "outside" perspective.

And as I don't want to play the semantics violin, I omitt the rest of my response.. x-D

Howgh.
Callippo
1 / 5 (4) Mar 08, 2012
My point being, that you simply can NOT suggest infinite space WITHOUT infinite time to support it (as you did in the above quoted sentence)
This is essentially what I argued a few pages of this thread before.
Callippo
1 / 5 (6) Mar 08, 2012
Funnily enough, both your comment, both Fleetfoot's one were upvoted with the same voting bots/trolls yyz and CardacianNeverid, who are apparently confused with subject of this discussion already.
CardacianNeverid
4.6 / 5 (11) Mar 09, 2012
Funnily enough, both your comment, both Fleetfoot's one were upvoted with the same voting bots/trolls yyz and CardacianNeverid, who are apparently confused with subject of this discussion already -ClappoZephyrTard

On this point you are 100% correct. You bring delusion and confusion into every thread you post in, so is it any wonder?
Kinedryl
1 / 5 (4) Mar 09, 2012
For contemporary scientists it's advantageous to keep as many conceptual models and theories as possible, because it helps them in employment. The more theories, the more theorists can keep their jobs. From this reason I'm providing single general concept/model, which enables to understand all these particular models in consistent way.

But because it threatens the social status and employment of many people involved into development of contemporary cosmology and formal education, it's just me who is accused from doing of confusion at the very end. Of course, the enhancing of the fact, the contemporary theories are logically inconsistent may appear like attempt for confusion of readers - but is it really the problem of mine?
Benni
1 / 5 (2) Mar 09, 2012
@Fleetfoot
@Darwalk

I appreciate your posts. The biggest problem I see with the geometry of the universe that infers "infinite parameters" is "information loss". This is the conundrum Hawking got caught up in & which Einstein avoided with his stand on a "closed & spherical" universe.

To me, a universe that has an infinite parameter, such as the "flat" or "saddle" universe, is a "leaky universe", subject to "information loss" (ie:energy). I'd like to get an opinion from one of the two of you why "information" (energy, photons) is not lost in a universe with an unbounded parameter such as the "saddle" or "flat".
CardacianNeverid
4.4 / 5 (7) Mar 09, 2012
For contemporary scientists it's advantageous to keep as many conceptual models and theories as possible, because it helps them in employment -AnotherZephyrSock

Delusional.

The more theories, the more theorists can keep their jobs -AnotherZephyrSock

Delusional.

But because it threatens the social status and employment of many people involved into development of contemporary cosmology and formal education -AnotherZephyrSock

Yep, scientists are only in it for the money and social status! Delusional - the reality is quite the opposite.

but is it really the problem of mine? -AnotherZephyrSock

Yes. Absolutely. And pick single handle already!
Kinedryl
1 / 5 (3) Mar 09, 2012
Yep, scientists are only in it for the money and social status!
As we know, they do it at least from forty percent already. According to this Scientific American editorial, 40% is typical.
Fleetfoot
5 / 5 (1) Mar 09, 2012
In addition, it was never observed - we observed only some kind of photon condensation inside of dense environment, where the photons gain positive rest mass.

BEC has been observed many time but mostly in alkaline earths:

http://en.wikiped...Isotopes

Apparently, mainstream physics converges to the dense aether model again.


Hardly. Try putting these together:

http://www.physor...rse.html

http://www.electr...time.htm

http://www.esa.in...x_0.html
Fleetfoot
5 / 5 (1) Mar 09, 2012
We now know that the universe is flat with only a 0.5% margin of error
We know, the Universe expands with accelerating speed, so it cannot be flat ..


You understand that omega=1 corresponds to flat. The main contributions to omega are:

dark energy 0.72
dark matter 0.23
IGM plasma 0.04
visible matter 0.01

http://www.univer...ventory/

The total is 1.00 to the WMAP accuracy so the universe is very close to flat. The dark energy part is what causes expansion to accelerate, if it was all matter expansion would still be slowing.

In addition, even if the Universe is flat, the limited speed of light implies rather strict limit for the Universe size, which may be only 250x larger, than the observable Universe size.

http://arxiv.org/abs/1101.5476


The important words there are "a lower limit", the finite speed of light only defines what is observable, an infinite universe is a standard prediction of the LCDM model.
Fleetfoot
5 / 5 (2) Mar 09, 2012
To me, a universe that has an infinite parameter, such as the "flat" or "saddle" universe, is a "leaky universe", subject to "information loss" (ie:energy). I'd like to get an opinion from one of the two of you why "information" (energy, photons) is not lost in a universe with an unbounded parameter such as the "saddle" or "flat".


Interesting question. My immediate reaction would be that that photons are only moving around within the universe, not being lost so I can't see any mechanism for a "leak". Redshift seems to lose energy but energy is frame-dependent so it is no worse than the Doppler effect. The whole subject is however much more complex. This is the physics FAQ article on the question which says more than I could:

http://math.ucr.e..._gr.html
Fleetfoot
5 / 5 (1) Mar 09, 2012
Hubble wrote:

"If the redshifts are a Doppler shift, then observations as they stand lead to the anomaly of a closed universe, curiously small and dense, and, it may be added, suspiciously young. On the other hand, if redshifts are not Doppler effects, these anomalies disappear and the region observed appears as a small, homogeneous, but insignificant portion of a universe extended indefinitely both in space and time."


Close, he only got the infinite age part wrong. Compare that with what I said a few posts back:

The HDF includes galaxies up to a redshift of 6 while the distance between us and galaxies at a redshift of about 1 was increasing by about 1 light year per year. That's one reason why you cannot use a model with galaxies moving through space and redshift caused by Doppler shift, you have to use GR and the model of expanding space.
Fleetfoot
5 / 5 (1) Mar 09, 2012
The tenet being, that SPACE and TIME are ONE entity.

There is no such thing as space without time (and vice-versa), up to a point where one could even say that space is an emergent property of time. ... My point being, that you simply can NOT suggest infinite space WITHOUT infinite time to support it (as you did in the above quoted sentence).


Emergence is a more complex question but certainly they are interchangeable to a degree. However, that doesn't mean both must be infinite, only that wherever you have space you also have time. Have a look at the grahic below the Mercator Projection near the bottom of Ned Wright's tutorial here:

Seeing as you are baseing it on Omega, perhaps "no limit" (from intrinsic perspective) would have been more fitting than "infinite extent" in this case?


I'm using what is standard terminology in the subject. This paper may be of interest, compare figure 2 with Ned Wright's graphic:

http://arxiv.org/.../0102010
Fleetfoot
5 / 5 (1) Mar 09, 2012
I've had to trim to <1000 chars
I explain..

[Omega > 1] - ...

[Omega = 1] - could be called "Schwarzshild unity" in the BH slang :-)

[Omega < 1] - is where my brain refuses to cooperate, ...

So yes, for [Omega > 1], from the "inside" perspective, you can move towards the "edge" but never be able to reach it, giving an impression of infinite freedom (eg. infinite extent), but this is just an illusion, as essentially you would be "moving in circles" at some point.

This is not the same as "infinite extent", ...


The diagram on the right here may perhaps help:

http://en.wikiped...Universe

The top image of a sphere shows a closed universe with the big bang at the bottom and the big crunch at the top. A horizontal slice is a circle representing the volume of the universe at that epoch. You can think of a small patch near the "equator" as a Minkowski spacetime diagram.

The other two are for flat and negative curvature and both are infinite in extent.
Fleetfoot
5 / 5 (1) Mar 09, 2012
The first link got lost in my previous post:

Have a look at the graphic below the Mercator Projection near the bottom of Ned Wright's tutorial here:


http://www.astro....o_03.htm

This paper may be of interest, compare figure 2 with Ned Wright's graphic:

http://arxiv.org/.../0102010

Fleetfoot
5 / 5 (1) Mar 09, 2012
After finding of red shift Hubble wrote six years later:

http://www.zkraco...z/6pjE6V


Note at the bottom of page 507 it states that the paper adapted a formula previously derived by Tolman. It is now known as the "Tolman Test". Note also that in item 3 just above the footnotes it is mentioned that Eddington had cautioned that there was an assumption that all galaxies had the same brightness.

This article gives a summary of more modern results:

http://en.wikiped...ess_test
Moebius
1 / 5 (1) Mar 10, 2012
Most of the energy in the universe was concentrated in suns during the early universe, probably after inflation had finished. Now they are releasing that energy into space at an accelerating pace. Seems logical that the expansion is speeding up.
Fleetfoot
5 / 5 (2) Mar 10, 2012
Most of the energy in the universe was concentrated in suns during the early universe, probably after inflation had finished.


If inflation happened as is currently thought, it finished around 10^-32s.

Nucleogenesis happened when the universe was a few seconds to a few minutes old.

The light we see as the CMBR was emitted from the hot plasma when it was around 378,000 years old after which the universe was filled with little more than thin, cool hydrogen/helium gas mix.

The first stars couldn't form until it was 30 million to 130 million years old (depending on details of simulations).
YawningDog
3 / 5 (2) Mar 10, 2012
All these comments sound like a bunch of blind men trying to describe an elephant.
PS3
1 / 5 (2) Mar 10, 2012
Is it possible that the stretch is from orbiting a larger mass and just happen to be at max whipping point?
Fleetfoot
5 / 5 (1) Mar 10, 2012
Is it possible that the stretch is from orbiting a larger mass and just happen to be at max whipping point?


If by "stretch" you mean the Hubble expansion then no, that would cause expansion in two directions (towards the mass and along the orbit) but contraction in the direction perpendicular to the plane of our orbit. There also seems to be no evidence of rotation though it is difficult to be sure.
Benni
1 / 5 (2) Mar 11, 2012
The first stars couldn't form until it was 30 million to 130 million years old (depending on details of simulations).


A gamma ray burst (GRB) has been recorded at 520 million years from BB/Infl. GRB's are associated with aging stars. This GRB proximity to the "first stars" at 30 - 130 million yrs seems awfullly close in time. I have looked at the charts which show the progression of a stars fusion rates until it starts to fuse iron.

If I subtract 130 from 520 I get mere 390 million years to the first GRB of a supposedly aging star. I'm very suspicious a star can progress to forming iron in its core at such a young age, leading me to believe the Universe is a lot older than 13.7 billion years. The redshift of that GRB is z=9.2, that is on the cusp of the supposed boundary of the universe that existed 13.7 billion light years ago. I will not be surprised when a GRB at z=10 shows up, that puts us inside the 30-130 million year before the first stars formed... cont'd..
Benni
1 / 5 (2) Mar 11, 2012
cont'd

...If after a GRB at z=10 is detected we, in my opinion, are looking at a universe having formed longer than 13.7 billion years ago. Then if we start seeing them at z=11, then 12, then 13, cosmology will go into a new metamorphisis.

The "new metamorphisis" will support Einstein's concept of a "spherical universe", & detract from the "flat universe" concept because the boundary of the universe at increased redshift beyond z=10 must shift, this allows for smaller curvature over a longer distance before the full cicumference of Einstein's sphere is realized.

I look upon the "flat" or "saddle" universe with great suspicion due to the "infinity" parameter of each. Any infinity parameter strongly hints at "loss of information", hence Einstein's conclusion of a spherically closed Universe in order that energy be conserved.

So far, no one has ever come up against Einstein & won, not even Einstein, he did it once & lost, the biggest blunder of his career.
Fleetfoot
5 / 5 (1) Mar 11, 2012
The first stars couldn't form until it was 30 million to 130 million years old (depending on details of simulations).


A gamma ray burst (GRB) has been recorded at 520 million years from BB/Infl. ... The redshift of that GRB is z=9.2


GRB's are associated with aging stars.

GRBs are thought to be from black holes, not stars.

I have looked at the charts which show the progression of a stars fusion rates until it starts to fuse iron.


You need to look up "Pop III" stars. They were the first to form so there was nothing beyond Helium in them. H and He radiate poorly so their mass was much higher, maybe 300 times our Sun so they had lifetimes of less than 10 million years. The heavier elements weren't produced slowly but in the supernova at the end of its life, in just a few seconds perhaps.
Fleetfoot
5 / 5 (1) Mar 11, 2012
I will not be surprised when a GRB at z=10 shows up, that puts us inside the 30-130 million year before the first stars formed. .. If after a GRB at z=10 is detected we, in my opinion, are looking at a universe having formed longer than 13.7 billion years ago.


Most textbooks say the first stars formed around z=25 which is 132 million years. Recent simulations which note that since dark matter doesn't interact with light therefore doesn't feel radiation pressure allow it to collapse earlier and put the first stars at z=65 which is 32 million years.

WMAP suggests reionisation wasn't a sudden event but gradual, starting around z=25 but possibly higher. JWST is designed to investigate out to z=15 or more.

We can already see the CMBR from z=1090 and age 378,000 years so finding anything later than that can only raise questions about our star formation theories, not the big bang.
Fleetfoot
5 / 5 (1) Mar 11, 2012
I look upon the "flat" or "saddle" universe with great suspicion due to the "infinity" parameter of each. ... So far, no one has ever come up against Einstein & won, ...


Exactly, and infinite extent is what his models predict for a flat universe, to go against that you need to discard GR.

Any infinity parameter strongly hints at "loss of information", hence Einstein's conclusion of a spherically closed Universe in order that energy be conserved.


Energy isn't necessarily conserved in any of the models but it's a complex question. Dark energy conserves energy because it acts as a negative pressure in gravitational terms.

However, what you should consider is that for the flat universe, the negative gravitational potential energy exactly balances the positive energy of matter, radiation etc. so the total is zero. The Hamiltonian of a closed universe is also zero so energy is conserved either way. That approach doesn't help us decide.
Benni
1 / 5 (2) Mar 11, 2012
at z=10 shows up, that puts us inside the 30-130 million year before the first stars formed. ..


Most textbooks say the first stars formed around z=25 which is 132 million years. Recent simulations which note that since dark matter doesn't interact with light therefore doesn't feel radiation pressure allow it to collapse earlier and put the first stars at z=65 which is 32 million years.

We can already see the CMBR from z=1090 and age 378,000 years so finding anything later than that can only raise questions about our star formation theories, not the big bang.


@Fleet: Great points. I guess I don't have the scale for redshift properly scaled for distance, it appears to be logarithmic formula from the numbers you've given me.

I'm curious, how'd you like the point I made about Einstein going up against Einstein & losing. My point being that whatever issue in science Einstein leans most heavily toward, is where the rest of us ought to be....
Fleetfoot
5 / 5 (1) Mar 11, 2012
@Fleet: Great points. I guess I don't have the scale for redshift properly scaled for distance, it appears to be logarithmic formula from the numbers you've given me.


Unfortunately it's a complex integral. The easy way is to use an applet like this one:

http://www.astro....alc.html

I'm curious, how'd you like the point I made about Einstein going up against Einstein & losing. My point being that whatever issue in science Einstein leans most heavily toward, is where the rest of us ought to be ...


I tend not to respond to such points, authority doesn't count for much because the data on which opinions are based is always moving forward. The equations of his theory are all that matters, so far they have never failed (in the range where they are applicable) so we have no reason to discard them. Einstein was wrong about QM and no human is infallible.
Callippo
1 / 5 (4) Mar 12, 2012
Einstein was wrong about QM and no human is infallible.
This article just says the opposite. Did you missed it?
Kinedryl
1 / 5 (3) Mar 12, 2012
It's quite easy to understand, where the hole in the quantum mechanics is. This is the result, which QM predicts for double slit experiment.

http://upload.wik...ated.jpg

And this is real result.

http://www.hitach...fig2.gif

It looks the same, but it's not the same: the paths of individual electrons are still observable. QM just cannot predict them.
Fleetfoot
5 / 5 (1) Mar 12, 2012
Einstein was wrong about QM and no human is infallible.
http://www.physorg.com/news/2012-03-physicist-einstein-beaten-bohr-famous.html#firstCmt just says the opposite. Did you missed it?


I was referring to Einstein's often quoted "God doesn't play dice with the world.". The article you quote is not relevant to that but instead refers to non-locality. AFAIK, the outcome of specific trials is still random in QM and can only be predicted statistically.

Regarding non-locality, Einstein's argument is stated mathematically in Bell's inequalities and the experiment by Aspect, repeated by many others for various particle types, showed that Bell's Inequality is violated in reality as predicted by QM. Einstein might have been able to win the argument, but he would subsequently have been proven to be wrong.
Fleetfoot
5 / 5 (3) Mar 12, 2012
This is the result, which QM predicts for double slit experiment.

http://upload.wik...ated.jpg

It looks the same, but it's not the same: the paths of individual electrons are still observable. QM just cannot predict them.


You can't see paths in either picture, all you see is where the particles were detected by the (photo-)multiplier plate.
Kinedryl
1 / 5 (3) Mar 12, 2012
You can't see paths in either picture
You can see the dots at the second picture or not? The QM can predict just the density of these dots - their exact location at the target is an additional bonus of information, which is not predicted/supplied with QM in any way.
Fleetfoot
5 / 5 (3) Mar 12, 2012
You can't see paths in either picture
You can see the dots at the second picture or not?


Yes, those are the points where the particles hit. You can't see what path they took to get there (in fact there is no unique path, the pattern is deterined by both slits). In the first picture, there are simply a lot more dots so the image doesn't resolve them.

The QM can predict just the density of these dots - their exact location at the target is an additional bonus of information, which is not predicted/supplied with QM in any way.


Exactly, QM predicts only the statistics, the place where the next dot will appear is random, to be determined by a throw of the dice in Einstein's phrase and contrary to his belief.
Kinedryl
1 / 5 (4) Mar 12, 2012
In the first picture, there are simply a lot more dots so the image doesn't resolve them.
Nope, this is a result of Schrodinger equation solution, i.e. the result of simulation, which you can play with at the Java applet here. QM predicts only the statistics, the place where the next dot will appear is random, but it's still observable. The result of experiment is richer just by this information. You can use this additional information for example in the sequence of weak measurements for determination of the whole path of particle during double slit experiment. http://www.nature...371.html
Fleetfoot
5 / 5 (3) Mar 12, 2012
In the first picture, there are simply a lot more dots so the image doesn't resolve them.
Nope, this is a result of Schrodinger equation solution, i.e. the result of simulation,


OK, you see the same if you use a bright light and do the experiment for real.

You can use this additional information for example in the sequence of weak measurements for determination of the whole path of particle during double slit experiment.

http://www.nature...371.html


I think you cited the wrong article, that one is about a triple slit experiment which only tested statistics, not paths.

Bottom line though is still that if you look at your original second image, there are only points of detection, no paths to those points. I have no idea what you think you are seeing.
Kinedryl
1 / 5 (2) Mar 12, 2012
OK, you see the same if you use a bright light and do the experiment for real.
Please, don't cheat..;-) This is a prediction of double slit experiment made with QM for both photons, both electrons. But the experimental result bellow is valid only for electrons.
I think you cited the wrong article
It seems, you're right - the citation of experiment which I had on mind is here
Iourii Gribov
1 / 5 (5) Mar 12, 2012
The Cosmological Constant (CC) for quantum Cooper-like (electron/positron) vacuum must be ZERO. It is weightless ghost superfluid, with the composite-ghostly SUSY. The underlying Gribov Pico-Periodical Multiverse (PPM) concept and Vallita's CPT- enlargement in the GR allow this conclusion. The PPM contains equal quantity of matter-antimatter, with theoretically estimated correct DE / (DM plus OM).. ratio ~74%/26%, if the CC=0. Matter and antimatter clusters are placed along 2D-bubble's surfaces and repeal each others, voids are empty. The Higgs bosons are excluded by the 3D-waveguided rest-mass creation mechanism. The equal periodical-overlapped Universes/Antiuniverses have the same SM-particles and physics. Our civilization is very young between plenty of developed hyper-civilizations (placed proximately near 10 -100 light minutes in a R4-distance around via Milky Way galaxy).
Fleetfoot
5 / 5 (1) Mar 12, 2012
OK, you see the same if you use a bright light and do the experiment for real.
Please, don't cheat..;-) This is a prediction of double slit experiment made with QM for both photons, both electrons. But the experimental result bellow is valid only for electrons.


Even though it is simulated, your upper picture would be typical for any double slit using a bright source, either light or electrons. Similarly, the lower image could also be the same experiment run with dim light or a low current of electrons. That's why I used the generic term "particles", you can't tell what was used.

I think you cited the wrong article
It seems, you're right - the citation of experiment which I had on mind is http://www.scienc...abstract


That story is what I thought you meant. I don't see it's relevance to what we were discussing.
PS3
1 / 5 (3) Mar 12, 2012
I thought they solved which path they take in the slit experiment by using entanglement?
Fleetfoot
5 / 5 (2) Mar 13, 2012
I thought they solved which path they take in the slit experiment by using entanglement?


There's a readable description here:

http://scienceblo..._obs.php

"They haven't done anything to prove orthodox quantum mechanics wrong, though I can predict with confidence that there will be at least one media report about this that is so badly written that it implies that they did. In reality, though, their measurements are completely in accord with ordinary quantum theory. ... I confidently predict that there will be no shortage of crazy people trying to claim this as conclusive proof for their particular favorite interpretation of quantum theory."

I still can't see a connection to the discussion of the cosmological redshift or even to my statement that I don't give much credence to authoritative opinion, it is only the equations that matter.
Fleetfoot
5 / 5 (1) Mar 13, 2012
I thought they solved which path they take in the slit experiment by using entanglement?


I should have said that what they did was find the mean momentum of a large number of photons at different locations and use that to map the average of many "trajectories" in the way that iron filings map the flux lines of a magnet.
PS3
1 / 5 (2) Mar 13, 2012
I thought they solved which path they take in the slit experiment by using entanglement?


I should have said that what they did was find the mean momentum of a large number of photons at different locations and use that to map the average of many "trajectories" in the way that iron filings map the flux lines of a magnet.

I was thinking of the quantum eraser,but maybe I read it wrong?
Fleetfoot
5 / 5 (1) Mar 13, 2012
I was thinking of the quantum eraser,but maybe I read it wrong?


I think so. I don't have access to the full paper but the reviews don't mention using entaglement at all and there is no attempt to measure individual trajectories, just the average of a very large number. It only confirms QM's prediction of the overall statistics.
Pet_mar
1 / 5 (2) Mar 25, 2012
Why are somes scientist so determined to say that the Universe
is a result expansion and it still expands?
Does expansion hear more correct than explosion?
If we had a linear or nonlinear transformation of the Universe (expansion)
we would see something like a projection in space. Nothing more.
But the Universe is like a living objects - new galaxies, stars, planets
come to live.
The elemensts near the beginning of the big bang were quite different
than those we see in stars (synthesis od heavier elements from the lighter ones).
So there is much more in the Universe than a plain expansion.
Fleetfoot
5 / 5 (2) Mar 25, 2012
Why are somes scientist so determined to say that the Universe is a result expansion and it still expands?
Does expansion hear more correct than explosion?


If you think of a map of the galaxies, that map is currently expanding by about 1% every 200 million years everywhere. No matter how far away from here you looked, you would see the same overall picture. An explosion suggests a region in space filled with matter expanding into a void which is incorrect.

So there is much more in the Universe than a plain expansion.


Absolutely.