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#1
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Facts against BB Theory
Large scale structures
---------------------- From the web site "http://bigbangneverhappened.org" In the page "Dr Wright is wrong" "Galaxies are organized into filaments and walls that surround large voids that are apparently nearly devoid of all matter. These voids typically have diameters around 140-170Mpc(taking H=70km/sec/Mpc) and occur with some regularity[E. Saar, et al, The supercluster-void network V: The regularity periodogram", Astr. And Astrophys., vol. 393, pp1-23 (2002)]. These are merely the largest structures commonly observed in present-day surveys of galaxies. Still larger structures exist, but are few in number for the simple reason that they are comparable in size with the scope of the surveys themselves. Since the observed voids have galactic densities that are 10% or less of the average for the entire observed volume, nearly all the matter would have to be moved out of the voids[F. Hoyle and M.S. Vogeley, "Voids in the Point Source Catalog Survey and the Updated Zwicky Catalog", Astrophys. J., vol 566, pp.641-651, Feb. 20, 2002]. Measurements of the large scale bulk streaming velocities of galaxies indicate average velocities around 200-250km/sec[L.N. Da Costa et al, "Redshift-Distance survey of Early-type galaxies: dipole of the velocity field' Astrophys. J., vol 537, ppL81-L84, July 10, 2000]" "To give the maximum leeway to the BB theory, we look at work that assumes some explosive mechanism created the voids, which would be much faster than if they were formed by gravitational attraction. For a cold dark matter Big Bang model, the time T in years, of formation of a void R cm in diameter in matter with density n/cm3 and final, present-day, velocity V cm/s is[ J.J. Levin et al, Astrophys J. vol 389, p464]: T=1.03n-1/4V-1/2 R1/2 For V=220Km/sec, R=85 Mpc and n =2.4x10-7 /cm3 (assuming the ratio of baryons to photons, h=6.14x 10-10), T= 158Gy. This is 11.6 times as long as the Hubble time. Even if we increase n to reflect current assumptions about dark matter being some 6 times as abundant as ordinary matter, we still get 100 Gy, or 7.4 times the Hubble time. This is actually a bit worse than the figure we arrive at by just diving the distance moved by the current velocity, which ends up as 6.3 time the Hubble time. Detailed computer simulations, which also include the hypothesized "cosmological constant" run into the same contradictions, in that they produce voids that are far too small. Simulations with a variety of assumptions can produce voids as large typically as about 35 Mpc[S. Arbabi-Bidgoli, and V. Muller, arXiv:astrop-ph/0111581 Nov. 30, 2001], a factor of 5 smaller than those actually observed on the largest scales. In addition, such simulated voids have bulk flow velocities that are typically 10% of the Hubble flow velocities[J. D. Schmidt, B.S. Ryden and A.L. Melott, Astrophys. J., vol. 546, pp609-619] which mean that voids larger than 60Mpc, even if they could be produced in Big Bang simulations, would generate final velocities in excess of those observed, and voids as large as 170 Mpc would generate velocities of over 600km/s, nearly 3 times the observed velocities. Thus even with dark mater AND a cosmological constant, it is impossible for the Big Bang theory to produce voids as large as those observed today with galactic velocities as small as those today. As was true in 1991, the large-scale structures are too big for the Big Bang. They in fact must be far older than the "Big Bang". ------------------------------------------------------------------------ I have been insisting in examples of huge structures and objects just too close to the supposed "bang" for a long time here. I add a new example I haven't brought up before. We have the huge cluster of galaxies discovered recently. In the paper pointed to by the hubble site (http://hubblesite.org/pubinfo/pdf/2014/22/pdf.pdf) we can read : quote While clusters as massive as ACT-CL J0102?4915 are quite rare at its redshift, the cluster does not pose any significant difficulty for the standard lambda CDM cosmology provided its mass is in the lower portion of its statistically allowed mass range. end quote In other words, if we arbitrarily take the lower portion of the statistically allowed mass range everything is OK. Of course if we do NOT do that, obviously lambda CDM model is gone for good. This is typical of the tone of scientific articles in astronomy these days: Orthodoxy must be observed at all costs even if it implies taking scientifically wrong procedures like chgoosing the range of a statistically allowed range. [Mod. note: there is nothing wrong with pointing out that the error bars on data are consistent with the standard model. Indeed, it would be wrong to do anything else -- mjh] quote Our Chandra and VLT observations additionally show that ACT-CL J0102?4915 is undergoing a major merger with a mass ratio of approximately 2 to 1 between its subcomponents. We find no analogous high-mass merging systems, with properties broadly similar to ACT-CL J0102?4915, within any current large-volume cosmological N-body simulations (e.g., MICE, Cubep3m). end quote In other words: This is the first we discover and it fits barely the current cosmology if we cherry pick the data. There are none like this one in the current surveys, but other, bigger surveys or surveys that explore other parts of the sky could find others like this one. But with all othodoxy genuflexions, the authors still have the courage of writing: quote We expect that more detailed analysis of large cosmological simulations and better understanding of the propagation of the initial Gaussian fluctuations, particularly at high redshift, will be required to compare with the predictions of a lambda CDM model using massive systems like ACT-CL J01024915. end quote [Mod. note: non-ASCII characters removed. PLEASE DO NOT cut and paste non-ASCII characters from papers etc -- mjh] |
#2
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Facts against BB Theory
In article , jacob navia
writes: "To give the maximum leeway to the BB theory, we look at work that assumes some explosive mechanism created the voids, which would be much faster than if they were formed by gravitational attraction. For a cold dark matter Big Bang model, the time T in years, of formation of a void R cm in diameter in matter with density n/cm3 and final, present-day, velocity V cm/s is[ J.J. Levin et al, Astrophys J. vol 389, p464]: T=1.03n-1/4V-1/2 R1/2 For V=220Km/sec, R=85 Mpc and n =2.4x10-7 /cm3 (assuming the ratio of baryons to photons, h=6.14x 10-10), T= 158Gy. This is 11.6 times as long as the Hubble time. Even if we increase n to reflect current assumptions about dark matter being some 6 times as abundant as ordinary matter, we still get 100 Gy, or 7.4 times the Hubble time. This is actually a bit worse than the figure we arrive at by just diving the distance moved by the current velocity, which ends up as 6.3 time the Hubble time. Since Levin, Freese and Spergel are not sceptical of the big bang, my assumption is that this analysis misunderstands their work, uses it in a regime where it is not valid, or deliberately misrepresents it. If this is really a killer argument against the standard ideas of structure formation, people who believe it should put their effort in getting a statement from one or more of these authors: why do they still believe the standard cosmological model if their own work suggests otherwise? Unless such a statement is forthcoming, or a documented refusal to comment, my default explanation will be the one in the first sentence of this paragraph. |
#3
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Facts against BB Theory
Le 21/04/2014 10:26, Phillip Helbig---undress to reply a ecrit :
Since Levin, Freese and Spergel are not sceptical of the big bang, my assumption is that this analysis misunderstands their work, uses it in a regime where it is not valid, or deliberately misrepresents it. Excuse me but this is not a scientific argument. In a nutshell: the size of the voids is so huge that using normal speeds of galaxies it would take several times the "age of the universe" to void them. This is a fact that you apparently do not contest... If you say that the equations are wrong, or "taken out of context" it would be nice if you would bring something to back it up! In fact I do not care what the authors think about the big bang or about the necessity of sending people to the moon, or the size of their wifes's hats. The equations shown are correct or not? If they are not please explain how the voids are created. Thanks for your input. jacob |
#4
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Facts against BB Theory
In article , jacob navia
writes: Le 21/04/2014 10:26, Phillip Helbig---undress to reply a ecrit : Since Levin, Freese and Spergel are not sceptical of the big bang, my assumption is that this analysis misunderstands their work, uses it in a regime where it is not valid, or deliberately misrepresents it. Excuse me but this is not a scientific argument. In a nutshell: the size of the voids is so huge that using normal speeds of galaxies it would take several times the "age of the universe" to void them. This is a fact that you apparently do not contest... I looked at the paper (which I had never heard of before), but didn't read it in detail. It is quite technical. However, all three authors are major players in cosmology and if they had disproved the big bang or whatever I'm sure that I would have heard of it before now. In fact I do not care what the authors think about the big bang or about the necessity of sending people to the moon, or the size of their wifes's hats. The equations shown are correct or not? If they are not please explain how the voids are created. Let me ask another question. Suppose I take the time to read through this paper and explain to you why it does not disprove the big bang. Would that convince you? |
#5
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Facts against BB Theory
On Wednesday, April 23, 2014 4:40:01 PM UTC-4, Phillip Helbig---undress to reply wrote:
Let me ask another question. Suppose I take the time to read through this paper and explain to you why it does not disprove the big bang. Would that convince you? -------------------------------------------------- This thread is not about "disproving" the Big Bang model. It is about the status of the Big Bang model and various add-ons, with the idea of exploring where our cosmological assumptions are empirically supported and where they are little more than speculative guesses backed up mostly by hype and endless repetition. Matt Strassler's informed discussion of conventional cosmological thinking provides an open-minded starting point for useful discussions. http://profmattstrassler.com/2014/03...-are-reliable/ |
#6
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Facts against BB Theory
In article , "Robert L.
Oldershaw" writes: This thread is not about "disproving" the Big Bang model. Says who? That is certainly the agenda of many contributors. It is about the status of the Big Bang model and various add-ons, with the idea of exploring where our cosmological assumptions are empirically supported and where they are little more than speculative guesses backed up mostly by hype and endless repetition. Such a false dichotomy (either empirically supported or hype) is a caricature which is not helpful for serious discussion. |
#7
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Facts against BB Theory
On Saturday, April 26, 2014 4:30:01 AM UTC-4, Phillip Helbig---undress to reply wrote:
Such a false dichotomy (either empirically supported or hype) is a caricature which is not helpful for serious discussion. Rather than airing personal opinions and assumptions, I would like to see posters actually discuss the status of the Big Bang model, using Matt Strassler's discussion as a jumping off point. For example, do people agree with his division of the Big Bang scenario into red, orange and yellow zones (which characterize the confidence and testability of different parts of the models main events)? What do people think of the cold Inflationary event that precedes the hot Big Bang? What are the initial conditions? How did the infinitesimal cosmos go from very cold to very hot? Not to mention Why? [Mod. note: reformatted, quoted text trimmed -- mjh] |
#8
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Facts against BB Theory
On Wednesday, April 23, 2014 3:45:53 AM UTC-4, jacob navia wrote:
In a nutshell: the size of the voids is so huge that using normal speeds of galaxies it would take several times the "age of the universe" to void them. One of the spectacular successes of cold dark matter (CDM) cosmology is that it quantitatively explains the observed void structures. Because CDM does not interact electromagnetically, gravitational perturbations in the CDM can grow even in the radiation dominated early universe. Then because CDM contains most of the gravitational matter, it can subsequently guide the formation of baryon perturbations, with the most dense regions forming galaxies. (In a nutshell: the voids do not form by "explosions" or fast moving galaxies -- the void structure is there from the beginning.). We can simulate the formation of structure in the universe. using the perturbation spectrum derived from the microwave background, and the known densities of CDM and baryons. For example, Sutter et al. (2013, http://arxiv.org/abs/1310.7155) find nearly 1000 voids in the Sloan survey, and compare these with their cosmological simulations, and conclude: "Our void abundances, ellipticity distributions, and radial profiles all indicate that voids in theory have the same sizes, shapes, and interior contents as observed voids." |
#9
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Facts against BB Theory
On Monday, April 28, 2014 4:13:04 PM UTC-4, wlandsman wrote:
One of the spectacular successes of cold dark matter (CDM) cosmology is that it quantitatively explains the observed void structures. ------------------------------------------------- What would have been truly spectacular is if some theory had actually *predicted* the vast filamentary cosmic web/void structure before there were observations that revealed this important cosmological clue. As far as I know, no theory did this but I am wiling to listen to counter-arguments. To me retrodictive model-building is not "spectacular", but rather is almost guaranteed to come up with several good explanations for the observed phenomenon, given a considerable number of motivated and talented theorists. |
#10
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Facts against BB Theory
In article , "Robert L.
Oldershaw" writes: On Monday, April 28, 2014 4:13:04 PM UTC-4, wlandsman wrote: One of the spectacular successes of cold dark matter (CDM) cosmology is that it quantitatively explains the observed void structures. ------------------------------------------------- What would have been truly spectacular is if some theory had actually *predicted* the vast filamentary cosmic web/void structure before there were observations that revealed this important cosmological clue. In a sense, this is what happened. The theory is Newtonian gravitation. It just happened that observations were more advanced than computing technology, so they were discovered before they were simulated and hence predicted from the theory. You can be sure that Newtonian gravity was not modified in any way in order to fit the observations. As far as I know, no theory did this but I am wiling to listen to counter-arguments. To me retrodictive model-building is not "spectacular", but rather is almost guaranteed to come up with several good explanations for the observed phenomenon, given a considerable number of motivated and talented theorists. In some cases, yes, but in this case, all one needs is Newtonian gravity and the background metric of the expanding universe. The general structure (filaments and voids) is quite generic. Just start with your particles and let gravity act. |
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