I posted a similar question earlier but framed it poorly. I understand that the redshift increases with distance. My question is whether the local expansion rate, the expansion rate at a point, is uniform through space, through time, and independent of local conditions.
No for another reason, which is due to variations of the mean energy density within the horizon, although more applicable to the early universe. The seed density variations set down from inflation and inflated over the apparent horizon with evolve locally like universes with different densities - so different expansion rates. As the horizon increases over the size of these variations will appears as pressure waves and gravitational waves and oscillate. Still the over dense regions with continue to expand more slowly with the under dense regions overtaking them to form the ~100Mpc voids that are seen.
The answer is "no" for various reasons.
Conditions within small regions can easily overcome global expansion, thus stars, galaxies and clusters do not expand, they are "gravitationally bound". Uniformity is only applicable on scales greater than tens of MPc where the Hubble Constant describes the mean rate.
The name "Hubble Constant" is also a bit misleading, it is constant throughout space but generally not in time. For the radiation and matter dominated eras, the Hubble constant varied as the inverse of time but it is tending towards a constant value in the future as dark energy (the cosmological constant) becomes dominant.
Expansion of the universe is defined in terms of Hubble Parameter. For any given epoch of the universe Hubble parameter can be treated as a constant and all calculations for that epoch can be performed with Hubble constant associated with that epoch. For example, Hubble constant for the present epoch is of order 10^(-18) in the units of time (s^(-1)). Hubble parameter at the beginning of the universe at the big bang moment was extremely high value. In my theory I use 10^(43) s^(-1). As the universe expands the Hubble parameter rolls down to the present low value over the period of ~13.7 billion years. In recent times it has been discovered that the universe is undergoing accelerated expansion. Basic formalism of the Lambda-CDM model could be found in the following articles (see pages 6 and 7 of both articles).
PJE Peebles and Bharat Ratra
http://arxiv.org/abs/astro-ph/0207347v2
EJ Copeland, M. Sami and S. Tsujikawa
http://arxiv.org/abs/hep-th/0603057v3
TDM: How is this possible? It isn't!
Correct. Arp was working on very limited data with serious problems of bias due to the limited sensitivity of the telescopes of his day and the use of photographic plates. Modern surveys showed that the patterns he saw didn't exist in reality.
There is a peak in some distributions but this is due to BAO which are well understood and actually a powerful tool, they can be used as a "standard ruler".
TDM: How come that the redshift is so different? It is due to the energy loss when it hits hydrogen. The recoil, as explained by Lyndon Ashmore, causes exaxtly the same values in a static universe as it gives in the alleged expanding universe.
Recoil also alters momentum scattering the photons. Looking at a distant source, those photons not deflected wouldn't lose energy either. See item D in Zwicky's paper (linked). Ashmore's statement that "linear momentum" is conserved is simply wrong.
That model also wouldn't produce stretching of light curves so it's ruled out in two ways. The static model is also gravitationally unstable of course.
http://www.pnas.org/content/15/10/773.full.pdf
No for another reason, which is due to variations of the mean energy density within the horizon, although more applicable to the early universe. The seed density variations set down from inflation and inflated over the apparent horizon with evolve locally like universes with different densities - so different expansion rates. As the horizon increases over the size of these variations will appears as pressure waves and gravitational waves and oscillate. Still the over dense regions with continue to expand more slowly with the under dense regions overtaking them to form the ~100Mpc voids that are seen.
There is now a very recent and very good determination of the (time dependence of the) Hubble parameter in the range 0.3
"Isn't it just the dogma of big bang that freezes science since a while?"
Thierry: I'm afraid it's rather glut of money that swamps and freezes parts of our cultural achievements, and funding helps erecting golden calfs.
Thierry, if I was analysing it these days, I would use the Klein-Nishina formula but the conclusion would be the same, the photon cannot lose energy to a free electron without a non-zero scattering angle.
No, according to our present knowledge, the expansion of the universe does not happen at the same rate at all points in space. However, at cosmic scales, it does ("Hubble law").
But in your question you speak of local expansion rate and local conditions : thus, one is obliged to answer "NO" because locally there might be (and are) differences in expansion rate. Just look at the enclosed graphical representation of "Hubble law" as found on Wikipedia ("Hubble_constant.jpg" - credit to :
Brews ohare - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6042242). One sees that there are some blueshifted constellations in the Virgo cluster (which is close to our cluster, thus not far away from us at cosmic scale). "Blueshifted" thus approaching us instead of moving away.
This is also shown on a "local" image of the sky in the following link : http://www.poyntsource.com/Richard/blueshifted_galaxies.htm
Concerning the present value of the Hubble parameter : as already mentioned, it is constant in space, not in time, still at cosmic scales thus, for both space and time, e.g. 1 Myrs are equivalent to 7.25 10-5 of the age of the universe (13,8 109 years ) thus very small if one wants to have significant changes of the Hubble parameter ....
The most recent value of the Hubble parameter is given by the 2015 results of the Planck mission : 67.8 +- 0.9 km.s-1.MPc-1. It can be seen together with other cosmological results in Table 9 at p. 27 of the enclosed summary of these measurements (Planck results_2015_1502 (2).pdf).
http://www.poyntsource.com/Richard/blueshifted_galaxies.htm
TDM: Who is talking of electrons of Compton?
Thierry, Ashmore is the one talking of electrons, here is his text:
"The plasma of Intergalactic space acts as a transparent medium and photons of light, as they travel through space, will be absorbed and re-emitted by the electrons in this plasma. At each interaction where the momentum of the photon is transferred to the electrons, there will be a delay. So the electron will recoil both on absorption and re-emission - resulting in inelastic collisions [15]. A double Mössbauer effect will occur during each interaction between photon and electron. Some of the energy of the photon will be transferred to the electron, and since the energy of the photon has been reduced, the frequency will reduce and the wavelength will increase. It will have ‘undergone a red-shift’."
Throughout that description, he says the energy is transferred to electrons and the title of the paper above specifically refers to "The Electrons In The Plasma Of Intergalactic Space"
Note however that he describes this as a "double Mössbauer effect". The Mössbauer effect is nothing to do with electrons however, it is an effect related solely to specific spectral lines in the gamma spectrum of the nucleus of atoms. Furthermore, this only occurs if the atom is bound in a solid, it doesn't even occur in the gas phase, never mind plasma, because individual nuclei have too little mass. The Mössbauer effect is also "recoiless" so no energy is lost as kinetic energy and since it is an emission prompted by a change of state of the nucleus, it occurs as a fine spectral line, so to try to use it as an explanation for Tired Light is nugatory.
His subsequent calculations also use cross sections for atoms which is silly because the IGM is, as he says in the title, a plasma. Even hydrogen nuclei would not be valid since they are single protons, only the helium nuclei could undergo a Mössbauer effect, and then only in the form of solid helium! Next time you come across a crystal of solid helium, let me know.
Article: On the Uncertainty Principle
By: Mesut Kavak
I've just seen this posted on three different threads, that qualifies you as a "spammer", from the Monty Python song, "spam, spam spam".
Yes, of corse.
The simplest 6D-interpretation of expanding Universe agree with observations is given in
I. A. Urusovskii, Multidimensional Treatment of the Expanding Universe,
Physical Science International Journal, 4(8): 1110-1144, 2014.
Our three-dimensional universe is isotropic and homogeneous at distances of more than 300 million light-years. This means that the Universe is a three-dimensional sphere, and that the scale of inhomogeneities in the Universe 100,000 times smaller than the characteristic size of the Meta galaxy. 6D-cosmology gives for the radius of the Meta galaxy value 3980 Mpc. The length of the great circle of the Meta galaxy passing through its borders (particle horizon), can be taken as a characteristic size. Then the size of inhomogeneities in the Meta galaxy is 2π3980/100000 = 0.25 Mpc or 815,646 light-years, which is approximately equal to the average distance between galaxies.
In Euclidean spaces with the number of spatial dimensions of a large three the Lorentz transformations are obtained elementarily, if the proper time of an elementary particle assumed to be proportional to the path traversed by it in the extra space, supplementing the observed three-dimensional space until a Multi-dimensional space, provided that the elementary particles like photons, moving at the speed of light in the whole space. All areas of the universe larger than 300 million light years have the same properties. The universe is a three-dimensional sphere, expanding in the space of a higher dimension. Elementary treatment of a spin, isotopic spin, Heisenberg relations as well the magnetic moment of the electron all require 6 spatial dimensions. Therefore, cosmology must also take into account the 6 spatial dimensions of a complete space.
Six-dimensional interpretation of the expanding universe is built on the principle of simplicity. The simplest geometric object of finite size in the 6D-Euclidean space is a 5D-sphere. Therefore, the simplest 6D-interpretation of the expanding 3D-sphere is its representation as the intersections of three 5D-spheres expanding in the 6D-Euclidean space − three 5D-spherical frontiers of disturbances propagating in this space. Thus it is assumed that these perturbations occurred as a result of three separate ‘explosions’ in the centers of these 5D-spheres. Point of first contact of the three 5D-spheres corresponds to the location of the center of the three-dimensional universe in the 6D-space. The intersections of three N-dimensional spheres are three N-1-dimensional spheres, which, in turn, intersecting to form three N-2-dimensional sphere, etc.
The curvature of the universe as a three-dimensional sphere is defined as unity divided by the square of the radius of the sphere. Geometric and physical quantities of the Universe are given by consideration of the cosmological model with fixed free parameters of the theory. The theory contains 5 free parameters. These parameters are chosen so that the deviations of the compared values from each other were minimal. For the chosen parameters in the case N = 5, the many results of the theory and observations are compared. By this, the radius of the Universe is 7100 Mpc, the Meta galaxy radius is 3980 Mpc. The speed of light on our three-dimensional sphere and the speed of its radial expanding of this sphere are connected by Pythagorean’s theorem. Sum of the squares of the two speeds is assumed constant according to the principle of simplicity. By this the velocity of light was equal to zero when the radius of the Universe was less than 18 percent of the current one in the case N = 5. From this point the speed of light is constantly increasing, asymptotically tending to a constant limit. Increase the speed of light leads to increasing of proper energy of elementary particles and thermal energy of stars and planets.
Maximum of density distribution in redshift z inflow of total energy in the Universe per unit time is reached at . According to [16, L. Tresse et al., ‘The cosmic star formation rate evolution from z = 0 to z = 5 from VIMOS VLT Deep Survey,’ http://arxiv.org/astro-ph/0609005], the maximum rate of star formation is observed at .
This 6D-theory gives the deceleration parameter of expansion of the 3D-sphere of primary interest for comparison of observations: that equals 0.038 – the value obtained in [49, Rines K., Forman W., Pen U., Jones C. and Burg R.. Constraining with cluster gas mass fractions. Feasibility study. Astrophysical Journal. May 20, 1999; 517 (1), Pt. 1: 70-77] by the method of EMN (Evrard, Metzler, Navarro) not associated with Hubble constant. For universe expanding with acceleration, deceleration parameter is negative.
To the question "Where is the center of the Universe?" should be a simple answer:
The center of the universe as a three-dimensional sphere lies in the space of a larger number of dimensions outside the universe at equal distances to all points of the three-dimensional sphere.
Igor A. Urusovskii
TDM: George Dishman: you change my words and you are wrong.
Not at all, I quoted your exact words. You cited Ashmore's paper and he was talking about electrons bound to atoms in a massive structure but trying to apply that to free electrons in space. I quoted you the sections of his paper that made that clear.
TDM: Zwicky claimed that the light fatigue by the Compton effect was unlikely. However, the Compton effect has nothing to do with normal situations in space. Hence, his argument is simply false and stupid.
No, it is perfectly correct, he was listing mechanisms that were known at the time and showing why none of those worked. His arguments against Compton scattering (and the others he mentioned) are still valid and the aspects where he noted that observations of the time were limited have since been confirmed (such as the narrowness of redshifted spectral lines).
The information accumulated since Zwicky make all references to him worthless.
The rate of spatial expansion is governed by Hubble Parameter which is the same at all points in space and is presently equal to 71 km/s per megaparsec, as given by the WMAP.In other words, the expansion or the recession velocity increases with distance ,i.e., for 2 megaparsecs ,the expansion velocity is 142 km/s,
Matts, obviously more recent information has superseded Zwicky's paper but, given the information available to him at the time, to say "his argument is simply false and stupid." was untrue and merely slanderous.
Sure George I agree with you. But whom are you citing? I don't recall having said such bad words about Zwicky.
George, Thierry de Mees used the words "his argument is simply false and stupid" yesterday.
Exactly Matts, when I quote others I prefix their words with their initials so when I wrote the following, it was supposed to show that I was quoting Thierry:
- TDM: Zwicky claimed that the light fatigue by the Compton effect was unlikely. However, the Compton effect has nothing to do with normal situations in space. Hence, his argument is simply false and stupid.
Sorry if that caused any confusion.
To those who have answered no, the logic seems twisted. It is clear that local gravitation can overcome the expansion of space, but that does not mean the expansion is zero. It only means that local gravitation forces exceed the general local expansion. My question really revolves around whether the drivers of universal expansion are subject to any local or temporal variations, not if they are small enough that local conditions can overshadow them.
Larry, whenever you ask for general properties of the universe, you surpass the knowable. We base special relativity on the assumptions of homogeneity and isotropy, but we cannot reach very far out to confirm this. Such assumptions are useful only because they permit us to construct simplified models for the whole universe.
The drivers of the universal expansion may well be subject to local or temporal variations,at distances we cannot (yet) reach. If so, our world picture will have to be revised some day.
LLB: To those who have answered no, the logic seems twisted. It is clear that local gravitation can overcome the expansion of space, but that does not mean the expansion is zero.
The logic seems straightforward to me, it does mean the expansion is zero (or negative) within that region.
LLB: It only means that local gravitation forces exceed the general local expansion.
I think the problem may be that you are treating these as separate processes when they are really just the same process but with a different balance of energy density. In some regions (say galaxies in a forming cluster), the objects are moving together while galaxies on opposite sides of a cosmological 'void' are moving apart, but the large scale expansion of the universe is nothing more than the average of all those changes of separation. It is misleading to think of some underlying space which is stretching uniformly at an accelerating pace with distinct gravity laid on top trying to hold things together.
The simplest 6D-interpretation of expanding Universe agree with observations is given in
I. A. Urusovskii, Multidimensional Treatment of the Expanding Universe,
Physical Science International Journal, 4(8): 1110-1144, 2014.
Our three-dimensional universe is isotropic and homogeneous at distances of more than 300 million light-years. This means that the Universe is a three-dimensional sphere, and that the scale of inhomogeneities in the Universe 100,000 times smaller than the characteristic size of the Meta galaxy. 6D-cosmology gives for the radius of the Meta galaxy value 3980 Mpc. The length of the great circle of the Meta galaxy passing through its borders (particle horizon), can be taken as a characteristic size. Then the size of inhomogeneities in the Meta galaxy is 2π3980/100000 = 0.25 Mpc or 815,646 light-years, which is approximately equal to the average distance between galaxies.
In Euclidean spaces with the number of spatial dimensions of a large three the Lorentz transformations are obtained elementarily, if the proper time of an elementary particle assumed to be proportional to the path traversed by it in the extra space, supplementing the observed three-dimensional space until a Multi-dimensional space, provided that the elementary particles like photons, moving at the speed of light in the whole space. All areas of the universe larger than 300 million light years have the same properties. The universe is a three-dimensional sphere, expanding in the space of a higher dimension. Elementary treatment of a spin, isotopic spin, Heisenberg relations as well the magnetic moment of the electron all require 6 spatial dimensions. Therefore, cosmology must also take into account the 6 spatial dimensions of a complete space.
Six-dimensional interpretation of the expanding universe is built on the principle of simplicity. The simplest geometric object of finite size in the 6D-Euclidean space is a 5D-sphere. Therefore, the simplest 6D-interpretation of the expanding 3D-sphere is its representation as the intersections of three 5D-spheres expanding in the 6D-Euclidean space − three 5D-spherical frontiers of disturbances propagating in this space. Thus it is assumed that these perturbations occurred as a result of three separate ‘explosions’ in the centers of these 5D-spheres. Point of first contact of the three 5D-spheres corresponds to the location of the center of the three-dimensional universe in the 6D-space. The intersections of three N-dimensional spheres are three N-1-dimensional spheres, which, in turn, intersecting to form three N-2-dimensional sphere, etc.
The curvature of the universe as a three-dimensional sphere is defined as unity divided by the square of the radius of the sphere. Geometric and physical quantities of the Universe are given by consideration of the cosmological model with fixed free parameters of the theory. The theory contains 5 free parameters. These parameters are chosen so that the deviations of the compared values from each other were minimal. For the chosen parameters in the case N = 5, the many results of the theory and observations are compared. By this, the radius of the Universe is 7100 Mpc, the Meta galaxy radius is 3980 Mpc. The speed of light on our three-dimensional sphere and the speed of its radial expanding of this sphere are connected by Pythagorean’s theorem. Sum of the squares of the two speeds is assumed constant according to the principle of simplicity. By this the velocity of light was equal to zero when the radius of the Universe was less than 18 percent of the current one in the case N = 5. From this point the speed of light is constantly increasing, asymptotically tending to a constant limit. Increase the speed of light leads to increasing of proper energy of elementary particles and thermal energy of stars and planets.
1. Maximum of total energy inflow density distribution by redshift z in the Universe per unit time is reached at z = 1.134. According to [16, L. Tresse et al., ‘The cosmic star formation rate evolution from z = 0 to z = 5 from VIMOS VLT Deep Survey,’ http://arxiv.org/astro-ph/0609005], the maximum rate of star formation is observed at z = 1.1. In 6D-theory evolution of the Universe does not depend on the density of the substance therein.
This 6D-theory gives the deceleration parameter q0 of expansion of the 3D-sphere of primary interest for comparison of observations: q0 that equals 0.038 – the value obtained in [49, Rines K., Forman W., Pen U., Jones C. and Burg R.. Constraining with cluster gas mass fractions. Feasibility study. Astrophysical Journal. May 20, 1999; 517 (1), Pt. 1: 70-77] by the method of EMN (Evrard, Metzler, Navarro) not associated with Hubble constant. For universe expanding with acceleration, deceleration parameter is negative.
To the question "Where is the center of the Universe?" should be a simple answer:
The center of the universe as a three-dimensional sphere lies in the space of a larger number of dimensions outside the universe at equal distances to all points of the three-dimensional sphere.
Igor A. Urusovskii
Igor,
why do you repeat this contribution in several threads? It was in this thread 14 days ago.
The rate of spatial expansion is governed by Hubble Parameter which is the same at all points in space and is presently equal to 71 km/s per megaparsec, as given by the WMAP.
The more recent results (2015) of Planck satellite mission give 67.8 +- 0.9 km.s-1.MPc-1, which is a little bit less ...
There is still a little tension between measurements of the value using different methods. However, that number is just the average, there are variations due to local differences in the matter density.
Yes, indeed ! We are much tighter now after the Hubble (HST), WMAP, Planck missions with values between say 67 – 75 km.s-1.MPc-1, than we were 20 years ago.
Just remember the :
- 80 ± 17 km.s-1.MPc-1 of W.L. Freedman et al. in 1994 (Nature, 371 :757-762, 1994)
compared to the :
- 30 km.s-1.MPc-1 of J.G. Bartlett et al. in 1995 (Science, 267 :980-983, 1995)
The simplest 6D-interpretation of expanding Universe agree with observations is given in
I. A. Urusovskii, Multidimensional Treatment of the Expanding Universe,
Physical Science International Journal, 4(8): 1110-1144, 2014.
Our three-dimensional universe is isotropic and homogeneous at distances of more than 300 million light-years. This means that the Universe is a three-dimensional sphere, and that the scale of inhomogeneities in the Universe 100,000 times smaller than the characteristic size of the Meta galaxy. 6D-cosmology gives for the radius of the Meta galaxy value 3980 Mpc. The length of the great circle of the Meta galaxy passing through its borders (particle horizon), can be taken as a characteristic size. Then the size of inhomogeneities in the Meta galaxy is 2π3980/100000 = 0.25 Mpc or 815,646 light-years, which is approximately equal to the average distance between galaxies.
In Euclidean spaces with the number of spatial dimensions of a large three the Lorentz transformations are obtained elementarily, if the proper time of an elementary particle assumed to be proportional to the path traversed by it in the extra space, supplementing the observed three-dimensional space until a Multi-dimensional space, provided that the elementary particles like photons, moving at the speed of light in the whole space. All areas of the universe larger than 300 million light years have the same properties. The universe is a three-dimensional sphere, expanding in the space of a higher dimension. Elementary treatment of a spin, isotopic spin, Heisenberg relations as well the magnetic moment of the electron all require 6 spatial dimensions. Therefore, cosmology must also take into account the 6 spatial dimensions of a complete space.
Six-dimensional interpretation of the expanding universe is built on the principle of simplicity. The simplest geometric object of finite size in the 6D-Euclidean space is a 5D-sphere. Therefore, the simplest 6D-interpretation of the expanding 3D-sphere is its representation as the intersections of three 5D-spheres expanding in the 6D-Euclidean space − three 5D-spherical frontiers of disturbances propagating in this space. Thus it is assumed that these perturbations occurred as a result of three separate ‘explosions’ in the centers of these 5D-spheres. Point of first contact of the three 5D-spheres corresponds to the location of the center of the three-dimensional universe in the 6D-space. The intersections of three N-dimensional spheres are three N-1-dimensional spheres, which, in turn, intersecting to form three N-2-dimensional sphere, etc.
The curvature of the universe as a three-dimensional sphere is defined as unity divided by the square of the radius of the sphere. Geometric and physical quantities of the Universe are given by consideration of the cosmological model with fixed free parameters of the theory. The theory contains 5 free parameters. These parameters are chosen so that the deviations of the compared values from each other were minimal. For the chosen parameters in the case N = 5, the many results of the theory and observations are compared. By this, the radius of the Universe is 7100 Mpc, the Meta galaxy radius is 3980 Mpc. The speed of light on our three-dimensional sphere and the speed of its radial expanding of this sphere are connected by Pythagorean’s theorem. Sum of the squares of the two speeds is assumed constant according to the principle of simplicity. By this the velocity of light was equal to zero when the radius of the Universe was less than 18 percent of the current one in the case N = 5. From this point the speed of light is constantly increasing, asymptotically tending to a constant limit. Increase the speed of light leads to increasing of proper energy of elementary particles and thermal energy of stars and planets.
1. Maximum of total energy inflow density distribution by redshift z in the Universe per unit time is reached at z = 1.134. According to [16, L. Tresse et al., ‘The cosmic star formation rate evolution from z = 0 to z = 5 from VIMOS VLT Deep Survey,’ http://arxiv.org/astro-ph/0609005], the maximum rate of star formation is observed at z = 1.1. In 6D-theory evolution of the Universe does not depend on the density of the substance therein.
This 6D-theory gives the deceleration parameter q0 of expansion of the 3D-sphere of primary interest for comparison of observations: q0 that equals 0.038 – the value obtained in [49, Rines K., Forman W., Pen U., Jones C. and Burg R.. Constraining with cluster gas mass fractions. Feasibility study. Astrophysical Journal. May 20, 1999; 517 (1), Pt. 1: 70-77] by the method of EMN (Evrard, Metzler, Navarro) not associated with Hubble constant. For universe expanding with acceleration, deceleration parameter is negative.
To the question "Where is the center of the Universe?" should be a simple answer:
The center of the universe as a three-dimensional sphere lies in the space of a larger number of dimensions outside the universe at equal distances to all points of the three-dimensional sphere.
Igor A. Urusovskii
IAU: The simplest 6D-interpretation of expanding Universe ...
How many times have you posted this spam Igor?
- Badges
- Science topic