1. No Final Answers in the Final Frontier

Remarkable advances in space science and cosmology have been made in the past half century with in-situ observations of planetary systems and space plasmas (interactive combinations of neutral particles, ions, electrons, and electromagnetic fields) and space-based platforms for astrophysics. Within the past two decades, important gains have been made in observations of very distant astronomical systems (most often associated with high red shift or ‘z’ value) that provide increasingly effective means of testing various models in physical cosmology. This evolution in observational capability has been accompanied by an even greater evolution in theory and modeling, much of which has enhanced the hot Big Bang (BB) research program which, by consensus, has come to be the dominant "standard model" in cosmology. As stated by Peebles (1993, p. 7), "the word ‘standard’ is meant to express the fact that there is a very significant body of evidence indicating that the hot big bang model is a useful approximation to the real world." There is broad agreement, even among detractors, that BB has provided the basis for numerous hypotheses, models, and a major motivation for important research programs such as the Hubble space telescope. Although not all cosmologists agree, the consensus of opinion is that BB-related theories and hypotheses, such as those concerning the cosmic background radiation, are backed by considerable evidence such that "the high-density, high-temperature beginning of the universe is a fact as secure as any in cosmology" (Harrison, 2000, p. 215).

The dustbins of history, however, are overflowing with discarded "facts" which turned out to be wrong. Almost no fact is truly secure in cosmology. New and challenging observational results and, for a growing number of scientists, persistent problems with BB hypotheses have encouraged research in and have supported alternative cosmological models. However, be it BB or alternative models, not a single theory so far proposed adequately explains or is consistent with all key observations. This may come as a surprise to those who have been taught that the BB is established "fact."

Consider for example, the basic premise of all BB models and most of their contenders, i.e. the requirement that in the "beginning" all of matter was concentrated into a singularity, in which space is not just infinitesimally small, but where there is no space at all, such that the amount of energy stored at the singularity also becomes infinite. In addition, as size decreases, energy levels increase and so does gravity. Yet, whether for the standard model or quantum physics, a subatomic, or quantum theory of gravity does not yet exist. At the singularity, and using "black holes" as an example, how is gravity overcome so as to give rise to an expanding universe that does not immediately fall back into itself? So far, no one has explained how the initial bang was ignited. — George Gamow himself (one of the BB originators) considered this as a major problem for BB (G. Gamow, personal communication, 1968).

2. Examples of Outstanding Issues in Physical Cosmology

Geoffrey Burbidge, eminent physicist and professor emeritus of the University of California San Diego, is one of many highly respected cosmologists who have questioned the validity of the big bang model and has pointed out many of its shortcomings: "there have been very few real predictions;" for example, "while the black body nature of the radiation was predicted by the big bang theory, the numerical value of the temperature was not, and cannot be" (Burbidge, 2006, p. 5).

Further, some scientists have taken umbrage at the willingness of BB modelers to embrace ad hoc assumptions as a means of patching over gaps in the "standard model" such as the inability to explain why most of the universe appears to be missing. For example, as critiqued by Burbidge (2006) BB theorists have resorted to hypothesizing the existence of invisible "dark matter" and "dark energy" to account for the 95% of mass-energy that is "missing," given BB assumptions. These assumptions, however, are then used to support yet other BB related theories such as current "scenarios" proposed for galaxy formation, which in turn "rests on this belief that this missing mass is real, because only if [cold, dark matter] exists in large measure is it possible to simulate galaxy formation at all" (Burbidge, 2006, p. 6).

The prevailing focus on assimilation and confirmation can also become problematic when transitions are made to even stronger claims. Clowe et al. (2006) for example, claim to have found "proof" of "dark matter," based on their interpretation of data from a galaxy collision. The Clowe et al. paper features some impressive technical arguments and then fails to consider a number of important and very critical caveats. In particular, the argument assumes that normal matter is fully accounted for by an inventory of visible stars and hot plasmas. However, it has been reported that non-visible interstellar gas, lower-energy plasmas and brown dwarfs, in combination, likely exceed luminous stars in the estimated mass of the nearby portion of our galaxy (e.g., Fuchs, Jahreiss, and Flynn, 2006). As summed up by philosopher of science James Hall, "Our hypotheses may get support or they may go down in flames, but they never, ever get proved" (Hall, 2005).

The same can be said of interpretations of the so-called Cosmic Microwave Background radiation (CMB). Because of its cool temperature, the BB modelers claim the CMB is conclusive evidence of cooling after a very hot beginning. However, the CMB could be due to a number of causes, including the burning of hydrogen.

Professor Burbidge points out that "none of this [elaborate theory] is necessary if we go back to the original observation of the ⁴He/H ratio and take the position that the observed ratio is the result of hydrogen burning in stars. Then of course, the whole of the mass must be baryonic" (Burbidge, 2006, p. 6). However, if solely baryonic, this would be fatal to BB models. Baryons are the family of composite particles made of three quarks and no anti-quarks. Baryonic matter is matter composed mostly of baryons (by mass), and includes nearly all matter that is typically associated with our known world, such as stars, planets, pets and people. Non-baryonic matter would include dark matter. BB models of nucleosynthesis require that in the beginning, equal amounts of baryons and antibaryons were produced. If the CMB was produced baryonically, then there was no big bang.

Burbidge then goes through a brief calculation that leads to black body radiation with temperature T~ 2.75°K, which is very close to the measured value of 2.726°K" the current temperature of the universe (see also Ibison, 2006). On this point, Burbidge (2006, p. 6) concludes that "This is either a pure coincidence, as it must be for those who believe in the big bang, or else it tells us that hydrogen burning was originally responsible for the CMB." Burbidge also calls attention to several estimates for the CMB which do not support the BB. A simple average of six such estimates made prior to the famed Penzias and Wilson measurement of 1965 yields ~3.1° K. In contrast, BB estimates by Gamow and collaborators ranged from 5 to 50° K (Assis and Neves, 1995; Peratt, 1995). Therefore, we have a number of close predictions that were entirely independent of the BB model. And yet, the typical scientific textbook account focuses entirely on Gamow’s BB "prediction" and the 1965 "confirmation" without reference to this history; the real story is far more complicated.

Other eminent scientists who have expressed concern about BB hypotheses include Halton Arp, Hermann Bondi, Thomas Gold, Jayant Narlikar, and Jean-Claude Pecker. In a comment on Arp’s critique of standard red shift accounts, Harrison (1981, p. 242) states that "When we leap to defend conventional wisdom we should remember that it cannot be proved true but only be proved false, and science is lost without those few people who are bold enough to interrogate its treasured doctrines."

Science should not be confused with democracy and the popular notion that the theory with the most "votes" wins. Facts are not determined by popular consensus but by the scientific method. Theories must be testable. If the theory fails the test, it should be substantially changed or abandoned, not merely appended with a patchwork of hypotheses and assumptions whose primary purpose is to support the theory or shield the underlying research program.

The Big Bang research program and its complex of theories are plagued with problems. These include:

• Age problem - Some high redshift objects appear to have ages greater than that of the BB universe (e.g., Jain and Dev, 2006);

• Anomalous alignments – Some alignments indicate non-primordial CMB components (e.g., Copi et al., 2006);

• Anomalous redshifts – strong evidence has emerged for non-expansion redshifts (Ratcliffe, 2009), and there are several viable frequency transfer processes available for quantitative testing (Marmet, 2009; Brynjolfsson, 2009);

• Black Hole questions - Black Holes may simply be neutron stars with accretion disks (Kundt, 2005, p. 108-112); also, fundamental QCD effects may prevent Black Hole formation (Royzen, 2009);

• Dark entities questioned - BB requires "dark" entities to fit galactic rotation curves, but some alternative analyses succeed without such hypotheses (Barak, 2009); further, dark entities require unknown non-baryonic physics (Capistrano, 2009);

• Dark matter missing - Direct experimental tests for "dark matter" have continued for over 25 years without any definite conclusion (e.g., Freeman and McNamara, 2006);

• Expansion problems - Cosmic expansion violates conservation of energy (Baryshev, 2008);

• Galaxy evolution correlates better with environment than with z value with both mature structures present at high z and young structures at low z, contrary to requirements of the standard model (Schawinski et al., 2009); also evidence for top-down vs. bottom-up evolution (Fontanot et al, 2009).

• Isotope anomalies - Given that ⁷Li is reduced by a factor of four in stars as required for BB, Lithium 6 (⁶Li) should be even more effectively destroyed, but is not (e.g., Steigman, 2006);

• Additional problems are discussed by Perivolaropoulos (2008). Further, numerous examples appear in monthly newsletters and conference publications of the Alternative Cosmology Group (see www.cosmology.info).

As an example of a straight-forward observational test and potential falsification, there is a clear prediction by the Robertson-Walker (R-W) geometry model (upon which BB depends; see Harrison, 2000, p. 298) that galactic surface brightness should decline with distance or redshift (z) as (z+1)^-3 (Peebles, 1993, p. 157). In contrast, all non-expanding cosmological models predict that surface brightness will remain constant with distance. Such a difference is not easily identified for relatively low z values typical of most astronomical observations. In the first surface brightness study to use high-z data from Hubble, observational results yield roughly constant surface brightness with z values up to 5.5 and thus appear to falsify R-W predictions (Lerner, 2006, 2009). No published critique of these results is yet available, but BB arguments about galactic evolution have been used to account for earlier reports at lower z of discrepancies with R-W prediction. However, such arguments appear ad hoc when applied to many more galaxies (Lerner’s analyses include over 100 galactic samples selected from a database of over 26,000 galaxies). For some, Ockham’s razor suggests a simple solution; namely a Euclidean (flat geometry) non-expanding universe (e.g., Montanus, 2005). Indeed, independent Bayesian model comparisons indicate that "the probability that the Universe is spatially infinite lies between 67% and 98 per cent...we find odds of order 50:1 (200:1) in favour of a flat Universe when compared with a closed (open) model (Vardanyan, Trotta and Silk, 2009, p. 431).

With new observational results coming available, there are many new opportunities arising for definitive tests and falsification instances for cosmology models. Nevertheless, continuing limitations of physical cosmology include the following:

• Lack of a unified field theory, which would unite gravity with the other force fields of physics; debates about string theory and other approaches illustrate this continuing debate (see Smolin, 2001).

• Like geology and unlike particle physics, cosmology is intrinsically an historical science and lacks direct experimental testing for many key hypotheses.

• Selection effects or Malmquist bias are often difficult to remove (e.g., Teerikorpi, 1998);

• The standard model is substantially weakened by having more free parameters than relevant observations (Disney, 2007; Goenner, 2009).

• Data in cosmology are limited to remotely sensed photons; there is no direct, in situ measurement as in space physics or planetary science. Most existing cosmology models focus on only one long-range force field (gravity) and ignore long-range effects of electromagnetism and plasmas, now well established through direct in situ observations of solar system space plasmas [e.g., Gurnett and Bhattacharjee (2004), and strongly indicated by x-ray observations of interstellar and intergalactic plasmas (e.g., Nicastro et al., 2005)].

On this last point, it is well known that electromagnetism is very effectively shielded out, which allows gravity to generally dominate over long scale lengths. Nevertheless, electromagnetism and plasmas can still be significant because there is typically a small but significant imbalance of charge in space plasmas, often on the order of 1 out of 10⁵; further, "By definition, plasmas are an interactive mix of charged particles, neutrals, and fields that exhibits collective effects. In plasmas, charged particles are subject to long-range, collective Coulomb interactions with many distant encounters. Although the electrostatic force drops with distance (~1/r²), the combined effect of all charged particles might not decay because the interacting volume increases as r³. Magnetic field effects are often global with their connections reaching to galactic scales and beyond" (Goedbloed and Poedts, 2004).

The potential importance of electromagnetism and plasmas is further indicated by the rapidly growing field of plasma astrophysics (NAS, 2004). As one example of its significance for altering conventional assumptions, Kundt (2005, p. 108-112, 144-146) shows in detail how observed signatures of existing candidates for "black-holes" can be more effectively interpreted as neutron stars with accretion disks or neutron star binaries. Efforts to assess the potential impact of the new plasma astrophysics on cosmology issues are just beginning (e.g., Peratt, 1991, 1995; Vasiliev, 2009).

Resolutions to be achieved in the coming century to some of the problems raised above may come from unexpected directions. For example, Reginald Cahill of Flinders University has introduced a new dynamical theory of space, which has become increasingly successful with explaining both ground-based and space-based experimental results (e.g., Cahill, 2009). Knowing that such innovative alternatives will receive little attention without rigorous laboratory experiments, Cahill has designed and implemented a state-of-the-art gravity detector based on coaxial cables, optical fibers and atomic clocks. Preliminary results appear to support Cahill’s predictions, which are also compatible with results of vacuum-mode experiments (Cahill, 2006). Another approach employing modified Newtonian dynamics (MOND) has become an increasingly strong competitor to standard cosmology (Milgrom, 2009).

3. Terminology

The term "cosmology" has often been used in ways that include both physical and philosophical aspects, the latter providing propositions that bridge from physical cosmology [contingent features of our actual world] to metaphysical propositions [necessary features of any possible world]. A common error arises from failing to make this distinction, which results in a confusion of science and philosophy and/or metaphysics and their proper domains. Murphy and Ellis (1996), for example, are careful about this distinction and illustrate possible linkages of physical cosmology with an integrative philosophical cosmology, along with cautionary notes. In particular, Ellis (2007, p. 1275) states that "Cosmology is not well served by claims that it can achieve more explanatory power than is in fact attainable, or by statements that its claims are verified when in fact the requisite evidence is unavailable, and in some cases must forever remain so."

Propositions in philosophical cosmology may be inspired by but should not depend on physical contingencies. In turn, for physical cosmology, our focus is on understanding deeper physical relationships among these contingencies. However, even though our scientific ideal is to achieve understanding of invariant relationships that are independent of historical context, actual scientific practice is always embedded in a particular history. For cosmology, historians Helge Kragh (1996, 2004) and Malcolm Longair (2006) have provided very insightful summaries of developments throughout the 20th century. Simon Mitton expands on this history with a focus on the life and work of Fred Hoyle (Mitton, 2005).

4. Constructive Program for Dialogue

For both aspects of cosmology as discussed above there are many relevant features in contemporary science that are common to available observations, BB and most alternative models, including among others:

• Evolution of systems at multiple levels [e.g., Kauffman (1995) for the evolution of biological systems and Goedbloed and Poedts (2004) for evolution in astrophysical systems];

• Hierarchies of complexity, from quantum to cosmos [e.g., Murphy and Ellis (1996) in their concise survey of the hierarchy of the sciences; and Chaisson (2006) in his survey of multiple epochs and hierarchies];

• Networks of relationships at multiple levels [e.g., Jungerman (2000) in a survey of interconnections in contemporary physics];

• Importance of both reduction (exclusive focus on efficient cause) and emergence with both bottom-up (efficient causality) and top-down causation [e.g., Laughlin (2005) and Ellis (2005) provide examples of emergent processes, which are more extensively illustrated by biophysicist Morowitz (2002) who surveys 28 major cases of emergence];

• Dualities without dualism arising from modern physics [e.g., both continuity and quantization; both symmetry and asymmetry, both particles and fields, see Eastman (2004)];

• Fine-tuning of physical systems [e.g., Koperski (2005)];

• Ultimate limitations of physical cosmology [e.g., Murphy and Ellis (1996)].

These common features are characteristics of some firmly established components of modern science (quantum theory, nonlinear dynamics, etc.) and appeal to less established theories in physical cosmology is generally not needed. The best science and philosophy results from sustained dialogue, sound methodology and openness to alternatives from both physical and philosophical cosmology. In the spirit of modern rational empiricism, we need to shift our focus from assimilation and confirmation to crucial tests and genuine prediction, made in advance (not just retrodiction), and falsification. Science provides understandings of the physical world achieved through successive and unending attempts at problem solving enabled by efforts towards ever greater coherence, consistency, and closure in observation, theory, hypothesis formation, modeling and simulation, and experiment. Science is constituted by such methodology and not by any particular content or results. For metaphysics and philosophical cosmology, the focus can remain on consistency and coherence (Whitehead, 1929), albeit with ultimate grounding in experience with a concern for applicability. However, in physical cosmology and science more broadly, linkages to observation and experiment are essential. Although complexities have arisen with all efforts to distinguish proper scientific propositions from non-scientific propositions, some helpful concepts have been developed, principally falsification (hypotheses should be falsifiable in principle) and Ockham’s razor (keep hypotheses as simple as possible).

It is often assumed that scientific methodology is fully characterized by the hypothetical-deductive framework. However, Niiniluoto, Ilkka, and Raimo Tuomela (1973) have shown the need for a hypothetical-inductive framework to characterize scientific practice that focuses on causal implication versus logical implication, and which maintains a different balance of theory, observation and experiment than that for the hypothetical-deductive framework. Further, based on recent advances in large databases, supercomputing, and knowledge discovery in databases (such as data mining), I have proposed an "observational-inductive" framework to describe methodologies arising from such a confluence of new technologies (Eastman, 2006; Mahootian and Eastman, 2009). In cases where very large datasets are available, some scientific problems may be more clearly resolved by deployment of the observational-inductive approach rather than by the theory-oriented hypothetical-deductive approaches that are currently prominent in physical cosmology.

5. Limitations

The domain of our direct knowledge of the cosmos has now reached to the outer solar system and is reflected in the great advances made in space physics (aka heliophysics) and planetary science in the past half century through both in situ observation and remote sensing. Even without the practical possibility of in situ observation, astrophysics has made similarly dramatic progress in understanding stars, galaxies, galactic clusters, and the intervening interstellar and intergalactic medium, although many fundamental questions remain for all these systems (Kundt, 2005). For physical cosmology, the fourth area of modern astronomy or space science, extrapolations from scientific foundations such as quantum theory, for which we have very high levels of confirmation, are being stretched to the limit. As stated by astrophysicist Wolfgang Kundt (2001, p. 611), "frontline physics is not as unique and reliable as the multiply tested physics of every-day life. The further the frontline advances towards unreachably large, or unresolvably small separations, or timescales…[the more] plausible assumptions have to replace redundant experience, and hasty interpretations can lead astray." One danger, according to Kundt, is that "Our politically organized society then takes care of suppressing minority opinion." Needed humility on these issues has extensive historical and philosophical grounds (Mahootian, 2009).

The Big Bang research program has been highly successful in generating fruitful scientific hypotheses and tests, and has achieved a significant level of confirmation for many hypotheses. However, outstanding questions remain and substantial alternative cosmology models, which also have been fruitful, remain viable and continue to evolve. For example, Kundt favors cold big bang cosmology (see Layzer, 1990); Burbidge and Narlikar favor a quasi-steady state cosmology (Hoyle, Burbidge, and Narlikar, 2000; Narlikar, 2002); Peratt and Lerner favor an updated plasma cosmology (Peratt, 1991; Lerner, 2003), and there are many others. It is at present unknown how BB or any of these alternative approaches will stand up to future tests using burgeoning new data sets and future critical tests and falsification instances. At the present time, I see both advantages and serious problems for all options – they may all be wrong – thus, the "agnosticism" in physical cosmology.