Showing posts with label George Smoot. Show all posts
Showing posts with label George Smoot. Show all posts

Tuesday, August 18, 2015

Is The Big Bang "Busted"? Not At All!

In  a recent issue of the Mensa Bulletin (June, p. 22) writer Dan Duda presents an article ('Is the Big Bang Busted?')  that basically invokes a highly speculative approach to reach a "conclusion" that dovetails with his "personal feeling that the Big Bang is a questionable theory". Fortunately, he does go on to concede this is "in spite of a significant amount of scientific evidence that supports it".

Significant indeed! Ii includes the presence of the uniform 2.7K cosmic microwave background radiation which a number of physicists (e.g. Steven Weinberg) have shown can only be traced back to the Big Bang. In fact, it was the discovery of this microwave radiation that earned Arno Penzias and Robert Wilson the Physics Nobel Prize, see e,g,

That Duda doesn't even mention this is incredible, given any decent science writer would have to be aware of the finding. And yet, Duda prefers to consider way out speculative (and mostly irrelevant) theories like simulated universes, as well as oddball cosmological theories like that recently trotted out by Ahmed Farag Ali (?) of Benha University and Saurya Das of the University of Lethbridge in Alberta, Canada.

My complaint is that even the intelligent and scientifically literate reader - say of the Bulletin, will come away even more confused, as opposed to educated. The National Science Board (a part of the National Science Foundation) has produced an annual survey of American beliefs about science called the Science and Engineering Indicators since the 1980s.   Americans - as reflected in the AP survey -  both seem to find the Big Bang confusing and worse, to have faith-based conflicts with the scientific conclusions of cosmology.
I attribute a lot of this to fake scientists - actually pseudo-scientists (like Jason Lisle) - who gain a peanut gallery following as well as prominence in the fundagelical religious sphere then profess to spiel on scientific issues like the Big Bang and the age of the Earth, confusing and undermining their followers.

Duda doesn't drag in specious religious bunkum but he does clutter his article with unusual complaints and fanciful conjectures that don't really have a bearing on the Big Bang,

For example, he cites a 1991 book 'The Big Bang Never Happened', wherein author Eric J. Lerner states:

"The Big Bang theory predicts that no object in the universe can be older than the Big Bang. Yet the large scale voids observed cannot have been formed in the time allowed."

Uh, yes they can! As I noted in an earlier post on these voids, e.g.


"Though the Hubble expansion limit is often cited as about 13.7 billion light years, this only refers to the extent that the radiating objects, galaxies, clusters, quasars etc. occur within our light cone. However, owing to the actual expansion of space itself, registered as a "comoving distance", the universe is really some 93 billion light years in diameter, so the actual edge of the observable universe is some 46.5 b light years distant."

In other words, those ancient, vast voids can definitely be accommodated. Duda's problem,  like that of the author he cites, is the failure to distinguish between the age of the cosmos registered within our own light cone and the physical extent defined as a comoving distance and actual expansion of space itself.  

In addition, Duda's citation of Lerner's 1991 work would have missed the discovery of the relic structures of the Big Bang (by George Smoot and his collaborators at the University of California at Berkeley,) in 1992. The investigation made use of data obtained from NASA's Cosmic Background Explorer (COBE) satellite. The data exposed very small temperature differentials (dT), from which density variations could be deduced. (In principle the temperature variations of the form dT/T are taken as a proxy for density fluctuations (dr / r)  in the early universe). These variations were also  found consistent with the postulated characteristics of an inflationary cosmos, as opposed to an always uniformly expanding cosmos. Indeed, an inflationary phase would feature an exponential rate of expansion by way of doublings over very small time periods.

The inflationary phase, with expansion rates in some cases exceeding the speed of light,  see e.g.

which could also have enabled the formation of the cosmic voids.

Duda's devotion of almost half his article to quantum aspects and collapsing wave functions is admirable, but really has no bearing on general relativity or the Big Bang. It is true that there could be a quantum 'tie-in' but the underlying theory - referred to quantum loop gravity - is still in its infancy.

Speculative excursions are indeed fascinating, especially in cosmology, but they shouldn't be used as filler for an article purported to be evidentiary or factual. A better title for Duda's piece would therefore have been: "Speculative alternatives to the Big Bang Theory".

Thursday, July 31, 2014

Re-Evaluating Our Cosmological Models: Why Now?



No photo description available.
In my 1964 Science Fair project, entitled 'The Structure of the Universe'  (which was given a feature look in the Miami Herald) I got many things wrong. The reason wasn't to do with errors, but in using the existing base of cosmological data and information to construct my model. Chief among these was the theory of continual creation which had been proposed by Fred Hoyle and Hermann Bondi.. It proposed that a hydrogen atom was ‘created’ in the universe on the basis of the perfect cosmological principle. A quantitative rate for the input-creation advanced by Jayant Narlikar ('The Structure of the Universe', Oxford Univ. Press, 1977) was:

4.5 x 10-45  kg m-3 s-1

This was taken to be the rate of new matter created per second within a cube - which is expanding at the rate H, where H is Hubble's constant. Then, one second later the side dimension of the cube will have increased by (1 + H)  and its volume will have increased to (1 + H)3 .  In this way, new matter is created within the 1 s interval with new mass: M = 3H r.

 And so,  though the universe was indeed expanding, it didn’t change its appearance. So its density must remain the same.  (The additional space created by the expansion must therefore have the same density of matter, r )   In addition, because of the principle of “continual creation”, the universe had no beginning and no end.  Thereby I was able to construct a model based on a matter and anti-matter universe (one with positive curvature the other, negative)  in a state of "equilibrium" with matter destroyed via annihilation equal to the new matter created via continuous creation.

It was a beautiful model which garnered top awards, but alas only months away from becoming passé.  This transpired when the first  evidence for the Big Bang emerged. This was thanks to Nobel-winning work by Arno Penzias and Robert Wilson. The experience showed me (as it did Fred Hoyle and Hermann Bondi) that our perspective on the universe and especially models, can change with just one major new discovery.

I based a lot of my model on the validity of the perfect cosmological principle which maintained that the universe was the same in space as well as time, and the same physical laws that apply on Earth applied everywhere else. In other words, our solar system and planet are nowhere special. Two sub-assumptions of the principle are that: 1)  the universe is homogeneous, i.e. looks the same for all locations, and 2) the universe is isotropic, appearing the same in all directions.

But back in the 1960s we still didn't know of the existence of cosmic voids. Those had to wait five decades for their discovery. Voids have roughly 1/10 the matter density of galaxy clusters (like our Local Group) but account for nearly 60 percent of the volume of the visible universe, thereby introducing inhomogeneity.

Even before the void discovery, there was the discovery of relic structures of the Big Bang by George Smoot and his collaborators at the University of California at Berkeley, in 1992. The investigation made use of data obtained from NASA's Cosmic Background Explorer (COBE) satellite. The data exposed very small temperature differentials (dT), from which density variations could be deduced. (In principle the temperature variations of the form dT/T are taken as a proxy for density fluctuations (dr / r)  in the early universe). These variations were also  found consistent with the postulated characteristics of an inflationary cosmos, as opposed to an always uniformly expanding cosmos. Indeed, an inflationary phase would feature an exponential rate of expansion by way of doublings over very small time periods.

What is the problem? It has remained trying to model a homogeneous universe despite data and findings that show the universe is inhomogeneous.  To quote astrophysicist Thomas Buchert (New Scientist, June, p. 33):

"To model such a complex structure with a homogeneous solution is a bold idealization."

Of course, cosmologists haven't been deterred. They merely resort to what's called modeling via  "statistical homogeneity" which means upping the scale for examining the cosmos to one wherein the inhomogeneities are radically reduced or vanish.  For example, on the scale of 400 million light years, voids and galaxy clusters average out into uniformity. But is this 'kosher'? Probably not because we have no real visualization of the cosmos on such scales.

Not yet mentioned are dark matter and dark energy, especially how the latter overturns our conceptions of cosmic order, see e.g.

Dark energy has also been found to be linked to the accelerated expansion of the cosmos, e.g.
Even more interesting, the cosmos' inhomogeneity contributes separately to the acceleration. Thus as more mass has clumped into galaxy clusters, the cosmic voids have grown causing the universe to expand more rapidly in those regions. The result is an accelerating effect similar to that attributed to dark energy but without any remote hint of it. (See e.g. The Journal of Cosmology and Astroparticle Physics, Vol. 10, p. 043).

What does all this mean for our cosmic perspective and cosmological models? Headaches! It means we may have to ditch the simplistic idealizations that pander to order, uniformity and aesthetics and instead come up with some ugly alternatives that violate our temperaments. For example, the whole Einsteinian notion of space-time is predicated on a continuum in which the entities are conjoined. But....if space expands at much faster rates in certain places then one must accept that clocks will tick at different speeds too.

As incredible as that sounds, it doesn't come near the ultimate conclusion: that if this is so it means the very age of the universe (which we now give as 13.8 billion years) is not a constant and instead will depend upon where the measurement is made. If you measure within a void you will get one answer, and in a galaxy cluster another. (According to one recent theory, it implies the age of the universe would be measured to be up to 18.6b years old where the low density of matter "means the clock has ticked particularly fast", New Scientist, op. cit. )

But which is better? To live with our idealistic fantasies of order and uniformity of space-time, or to live in reality and know the actual truth of how the universe operates?   Bear in mind the entire history of our science has been overturning sundry pet concepts of the universe, and especially our place within it.

Now may be the time for cosmologists to put on their big boy pants and devise theories which, although they may try the orderly temperament, are much closer to reality!