Tuesday, March 6, 2012

Cosmology

Did the universe have a beginning?

The big bang theory postulates that the entire universe originated in a cosmic explosion about 15 billion years ago. Such an idea had no serious constituency until Edwin Hubble discovered the redshift of galaxy light in the 1920s, which seemed to imply an expanding universe. However, our ability to test cosmological theories has vastly improved with modern telescopes covering all wavelengths, some of them in orbit. Despite the widespread acceptance of the big bang theory as a working model for interpreting new findings, not a single important prediction of the theory has yet been confirmed, and substantial evidence has accumulated against it.

Did the Universe Have a Beginning? Dr Tom Van Flandern

And Wikipedia tells us that

Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order. Modern cosmology is dominated by the Big Bang theory, which brings together observational astronomy and particle physics.

In recent times, physics and astrophysics have played a central role in shaping the understanding of the universe through scientific observation and experiment. What is known as physical cosmology shaped through both mathematics and observation the analysis of the whole universe. It is generally understood to begin with the Big Bang, followed almost instantaneously by cosmic inflation - an expansion of space from which the universe is thought to have emerged ~13.7±0.2×109 (roughly 13.5–13.9 billion) years ago.

Modern scientific cosmology is usually considered to have begun in 1917 with Albert Einstein's publication of his final modification of general relativity in the paper "Cosmological Considerations of the General Theory of Relativity," (although this paper was not widely available outside of Germany until the end of World War I). General relativity prompted cosmogonists such as Willem de Sitter, Karl Schwarzschild and Arthur Eddington to explore the astronomical consequences of the theory, which enhanced the growing ability of astronomers to study very distant objects. Prior to this (and for some time afterwards), physicists assumed that the Universe was static and unchanging.

Subsequent modelling of the universe explored the possibility that the cosmological constant introduced by Einstein in his 1917 paper may result in an expanding universe, depending on its value. Thus the big bang model was proposed by the Belgian priest Georges LemaƮtre in 1927 which was subsequently corroborated by Edwin Hubble's discovery of the red shift in 1929 and later by the discovery of the cosmic microwave background radiation by Arno Penzias and Robert Woodrow Wilson in 1964. These findings were a first step to rule out some of many alternative physical cosmologies.

What is wrong with This Picture?

Wikipedia also has an entry on Religious Cosmology, and if Eric Lerner is correct then the entry should also include a reference to Big Bang theory. According to Lerner, a ‘cosmological pendulum’ exists that swings through the course of history between a ‘scientific’ and a ‘mythological’ view of the cosmos (All references are taken from ‘The Big Bang Never Happened’, Lerner, E. 1991). According to Lerner, the evolution of cosmology depends on the evolution of society. As society swings between periods of progress and periods of crisis - sometimes lasting centuries, approaches to the cosmos alternate between progress based on empirical observation on the one hand, and regress based on a priori deductive inferences starting from mathematical axioms on the other.

Today Big Bang theorists see a universe much like that envisioned by the medieval scholars - a finite cosmos created ex nihlo, from nothing, whose perfection is in the past, and degenerating to a final close. The perfect principles used to form this universe can be known only by pure reason, guided by authority, independent of observation (Lerner, pg 6).

The first ‘deductive’ swing of the pendulum gave us the static and finite universe of Ptolemy, and the early Christian Church introduced the idea of creation from nothing, ‘decaying from a perfect beginning to an ignominious end’ (pg 7). But the pendulum swung back during the scientific revolution. In this, its empirical phase, cosmologists saw the universe as infinite in space and time, without origin or end; and, by the middle of the 19th century, the concept of universe was that of an unending process of evolution. But, in the early 20th century, the pendulum swung back in a startling return to ‘discredited medieval concepts’. The crises of the 20th century gave credibility to the ‘old philosophical view of a decaying universe, degenerating from its perfect origins, and to the deductive method.’ The new theory grew not from observation but from these pessimistic philosophical underpinnings. Hence, unsurprisingly, observation presents the greatest challenges to Big Bang Theory.

Empirical Challenges to the Big Bang Theory

Dr Tom Van Flandern has conveniently assembled the top thirty problems with the Big Bang Theory on his website. The following text shows the top ten:

1. Static universe models fit observational data better than expanding universe models. Static universe models match most observations with no adjustable parameters. The Big Bang can match each of the critical observations, but only with adjustable parameters, one of which (the cosmic deceleration parameter) requires mutually exclusive values to match different tests. Without ad hoc theorizing, this point alone falsifies the Big Bang. Even if the discrepancy could be explained, Occam’s razor favors the model with fewer adjustable parameters – the static universe model.

2. The microwave “background” makes more sense as the limiting temperature of space heated by starlight than as the remnant of a fireball.

3. Element abundance predictions using the Big Bang require too many adjustable parameters to make them work.

4. The universe has too much large scale structure (interspersed “walls” and voids) to form in a time as short as 10-20 billion years. The average speed of galaxies through space is a well-measured quantity. At those speeds, galaxies would require roughly the age of the universe to assemble into the largest structures (superclusters and walls) we see in space, and to clear all the voids between galaxy walls. But this assumes that the initial directions of motion are special, e.g., directed away from the centres of voids. To get around this problem, one must propose that galaxy speeds were initially much higher and have slowed due to some sort of “viscosity” of space. To form these structures by building up the needed motions through gravitational acceleration alone would take in excess of 100 billion years.

5. The average luminosity of quasars must decrease with time in just the right way so that their average apparent brightness is the same at all redshifts, which is exceedingly unlikely.

6. The ages of globular clusters appear older than the universe.

7. The local streaming motions of galaxies are too high for a finite universe that is supposed to be everywhere uniform.

8. Invisible dark matter of an unknown but non-baryonic nature must be the dominant ingredient of the entire universe. The Big Bang requires sprinkling galaxies, clusters, superclusters, and the universe with ever-increasing amounts of this invisible, not-yet-detected “dark matter” to keep the theory viable. Overall, over 90% of the universe must be made of something we have never detected.

9. The most distant galaxies in the Hubble Deep Field show insufficient evidence of evolution, with some of them having higher redshifts (z = 6-7) than the highest-redshift quasars.

10. If the open universe we see today is extrapolated back near the beginning, the ratio of the actual density of matter in the universe to the critical density must differ from unity by just a part in 1059. Any larger deviation would result in a universe already collapsed on itself or already dissipated.




Einstein’s Role

One always has to be careful criticising Einstein since the line between criticism and anti-Semitism (which I abhor) is sometimes a fine one. However, apart from the Wiki entry, it is not obvious from the above what role Einstein played in the development of modern cosmology. First, Einstein’s equations of General Relativity underpin Big Bang Theory. Second, he did not derive his equations from observation. Third, it is not obvious what problem he was trying to solve.

Hilton Ratcliff argues that ‘[it is] not that easy to find out precisely why – in a practical sense – Einstein objected to Newtonian physics, or whether in the cold light of day he made any real improvement to the situation’ (‘The virtue of Heresy’, Ratcliff, H. pg 260). He goes on to say that Einstein:

·        Was concerned with the propagation of light in the absence of a physical medium, but that notion had already been answered in Maxwell’s equations.

·        Had a big problem with ‘action-at-a-distance’ (especially gravitation), but his proposed field solution still acts on objects at a distance from each other.

·        Was understandably puzzled by wave-particle duality in light, but could not suggest a workable solution; it is still today one of the most vexing questions in physics.

·        The crucial objection he raised was to the notion of absolute, universal time and the simultaneity of events. We shall shortly see that in this regard Albert Einstein was being idealistically fanciful.

We will deal with Ratcliff’s illustration of Einstein’s idealism (as opposed to realism) in the Anti-Realism post.

Was Einstein was a victim of circumstances? – Albeit, in some respects, a fortunate one. His General Relativity model had non-empirical, deductive origins. The equations of the model are non-linear and massively ‘underdetermined’ (more variables than equations; more degrees of freedom than constraints). And whilst there may be an infinity of mathematical solutions to such models, few solutions make sense physically. For example, a simple schoolroom quadratic might give two perfectly good mathematical solutions for a person’s age; one positive and one negative. But common sense tells us to dispense with the negative solution because people do not have negative ages. Unfortunately, we have no ‘common sense’ about cosmology so we are without a guide to the correct solutions. Lerner says:

In general when equations describing physical reality produce singularities – solutions involving either zero or infinity – it is a sign that something is wrong, since scientists assume that only measurable, finite quantities should be predicted (Lerner, pg134, my emphasis). 

For the universe to expand it must be finite. But most scientists from the scientific revolution onwards believed the universe to be infinite both in time and space. Einstein laid the foundation for eliminating this idea. He assumed, against all the evidence then and now, that unstated forces distribute matter homogeneously throughout the universe. Given this and his idea that matter ‘curves’ the space around it, Einstein believed that the uniform distribution of matter would curve space right around itself. Hence, the universe, like the surface of a sphere, was finite but unbounded. So, based on the idea of curved space, Einstein’s equations laid the foundation for a finite, but expanding universe, and thereby also laid the foundation for the Big Bang.       

However, Einstein's equations are unstable; so, if left to itself, Einstein's universe would quickly collapse under the pressure of gravity. To offset this, Einstein introduced an ad hoc fudge factor, a repulsive variable to neutralise the contractionary effects of gravity called the cosmological constant. This stabilised Einstein's universe and made it static. Einstein later admitted that this was the biggest mistake of his professional career.

But a Belgium catholic priest, Georges LemaĆ®tre - a student of Eddington, the Scottish physicist who led the 1919 solar eclipse expeditions that claimed success for Einstein’s general theory of relativity - realised that the instability of Einstein’s universe was a gift from God.  Lemaitre showed that

Einstein’s universe is only one special solution [of the equations of general relativity] among infinite possible cosmologies – some expanding, some contracting, depending on the value of the cosmological constant and the ‘initial conditions’ of the universe (Lerner pg 133).

Adjust the value of the cosmological constant and as if by magic one has an expanding universe. And if the universe is expanding, then it must have started somewhere and somewhen.  The somewhen was the Big Bang. And the somewhere must be the centre of the universe. And since Hubble’s red shifts indicated that everything seemed to be moving away from Earth, the Earth must clearly lie at the centre of the universe. Of course neither scientific concerns, nor the ad hocery of Einstein’s cosmological constant motivated Lemaitre. Theosophical concerns were is primary motivation. Lemaitre believed that he had ‘scientifically’ confirmed nothing less than the Biblical creation itself.

But the evidence contradicted Lemaitre’s Big Bang Mark I, and it subsequently collapsed, as did Gamow’s Big Bang Mark II that followed at the end of the Second World War. Big Bang Mark III was borne of theories about the microwave cosmic background and the relative presence of three light elements – helium, deuterium, and lithium. Big Bang Mark IV (today’s Standard Model) incorporates an ad hoc theory of inflation which overcomes some of the inconsistencies of the earlier theories (Lerner, pg 156).

For the universe to be finite, which it must be in order to expand, there must be enough matter, sufficiently homogeneously distributed, to cause space to curve back on itself. The problem is that all the matter in the universe amounts to around 0.02% of that needed to cause such curvature, and what there is, is certainly not homogeneously distributed. Standard Model cosmologists therefore, again ad hoc, posit the existence of dark matter and dark energy to account for the missing 99.98%. What could such matter be? Cosmologists have sought help from particle physicists to see if they can identify the 99% of the universe that appears to be missing. Particle physicists are busily searching for this strange dark substance which no one has ever observed and which has none of the properties of ordinary matter, but which Standard Model theorists desperately need to save Big Bang Mark IV from itself.

Scientists can transform matter and energy into one another, but they cannot create either from nothing. Consequently, particle physicists are searching for the Higgs Boson, a magical sub-atomic particle, existing in a vacuum, which ‘generates all the needed energy from nothing’ (Lerner, pg 158). Wikipedia has this to say:

The Higgs boson is a small theoretical particle, which (if it exists) is created by a Higgs field. It is necessary for a set of rules in physics that we call the Standard Model, but it has yet to be found in an experiment. If the results of the work at CERN cannot show that the Higgs boson exists, much of our entire understanding of physics will need to be re-written. It is important in the scientific world because many scientists believe that it is responsible for giving mass to all known particles that have mass.

(My emphasis)

Cosmology and particle physics seem to have got themselves in a bit of a tangle. Lerner shows brilliantly, how cosmological speculation reflects financial speculation in the periods in which it occurs:

Throughout the decade [1980s], the rise of financial speculation in Wall Street was shadowed by the rise of cosmologists’ speculation in Princeton, Cambridge, and elsewhere. As Witten and his colleagues were acclaimed by the press as geniuses for theories that produced not a single valid prediction, so men like Michael Milken and Donald trump earned not only far greater fame but also incomes that peaked, in Milken’s case, at half a billion dollars per year for paper manipulations that added not a single penny to the nation’s production (Lerner, pg 166).                       

Percipient in the light of the CERN Large Hadron Collider’s failure to find the Higgs Boson, Lerner goes on to say:

If a tower of financial speculation could be built on debt – the promise of future payment – then, similarly, a tower of cosmological speculation could be built on promises of future experimental confirmation (Lerner, ibid.).

When cosmological speculation sits happily in the shadow of contemporary ideology; when it proceeds from the premise that the theory is so mathematically perfect that theorists must make the facts conform to it or ignore them altogether; when cosmologists continually make ad hoc adjustments analogous to Ptolemy’s epicycles; it seems clear that cosmological ‘science’ has indeed retreated from Copernicus back to Ptolemy or even earlier.  


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