If only because of its catchy title, the Big Bang model of our universe, forming from a massive explosion simultaneously creating both matter and time, has reached broad acceptance within both the scientific and general community.  However, the concept was not nearly so palatable when it was first proposed, in response to implications of Einstein’s General Theory of Relativity, and significant resources were lined up behind the alternate Steady State theory.  This report examines the factors driving the development of these two competing theories, the evolution of the debate over them, and the advances in our understanding of the universe that saw the Big Bang emerge as the preferred theory.

In the Beginning – the need for a model

“To admit such a possibility seems senseless” – Einstein’s thoughts on General Relativity’s predictions of the notion of a collapsing universe[i]. Einstein’s General Theory of Relativity had an enormous impact on the scientific community, and radically altered the way in which the universe was observed, and indeed, perceived.  Because of its complexity, in order to apply General Relativity to modeling the universe, Einstein started with the assumptions that the universe was isotropic and homogenous– that is was that same in all directions, and that one region was no different to another on a large scale (together known as the cosmological principle).  Although these postulates have been born out by observation, Einstein adopted them primarily to provide  a framework to test his theories. The resulting calculations showed a universe that was unstable, and thus liable to gravitational collapse.  This was counter to the prevailing view that the universe was static and eternal – a view Einstein shared.  The primary objection to an unstable universe was that the implied eventual collapse indicated a universe that was temporary – a notion that was very hard to accept at that time[ii]. In order to reconcile the predictions of his cherished General Relativity with his personal preferences, Einstein added a counterbalancing outward force to maintain equilibrium, his so-called cosmological constant. This ‘fudge-factor’ manifested itself as an anti-gravitational force that only operated at large distances, making it compatible with existing successes of General Relativity as well as a static, eternal universe[iii] [iv]. By way of contrast, Willem De Sitter offered an alternate model of the universe, consistent with General Relativity but not containing any matter[v].  Its chief theoretical importance was that it too produced an unchanging universe. Russian physicist Alexander Friedman worked with a number of values for Einstein’s cosmological constant, including a value of zero, omitting it completely.  Such a value suggested an initial ‘explosion’[vi].  Friedman’s work showed that matter and motion were possible under General Relativity and suggested a universe that was evolving over cosmic time-scales.  His paper “On the curvature of Space Time” was the first to suggest this notion in an analytical fashion.  However, as Friedman was a mathematician, not an astronomer, he sought no observational support for his predictions[vii].  Einstein initially dismissed Freidman’s work, but was later to acknowledge his error, and concede its  mathematical validity. In the early 1920s, astronomer Edwin Hubble discovered Cepheid variable stars in the Andromeda Nebulae (as it was then known), and by using the method relating luminosity to period established by Henrietta Lovett, was able to deduce a distance of 900,000 LY, placing it far outside the Milky Way galaxy.  Although often at pains not to attach interpretations to his findings, Hubble’s work conclusively answered the question over the nature of nebulae[viii], and, as all other galaxies were further away, had considerably expanded the size of the known universe. However, even greater contributions were to come when Hubble undertook a detail spectrographic study of galaxies, and determined via Doppler analysis that almost all galaxies[ix] displayed a red-shift in their spectra, indicating that they were moving away from the Milky Way.  Even more significantly, a relationship between distance and rate of recession was found, indicating the further away a galaxy was, the faster it was receding (see Figure 1).  Although not an active participant in the Big Bang debate, Hubble’s discovery almost certainly painted a picture of a universe that was expanding[x]. As a final contribution to this debate, Hubble measured the rate at which recession speed changed relative to distance, and arrived at a figure of 558 km/sec/Mpc.  Not only did this figure allow distances to be determined based on recession speed (as indicated by spectral red-shift), it also allowed for the first time, an observationally backed age of the universe – in this case 1.8 billion years.  Such was Hubble’s prestige, that this figure remained unchallenged for 20 years, despite being inconsistent with geological (and to some extents biological[xi]) observations.   Figure 1. Hubble's plot of redshift and distance[xii]   Georges Lemaître was a Belgian cosmologist, who was also a Catholic Priest.  Taking a different tack to Friedman, he also adopted General Relativity without a cosmological constant, and followed the consequences of an expanding universe backwards from the present time, finding has model balanced with General Relativity[xiii].  Applying the emerging knowledge in the fields of sub-atomic physics and nuclear fission, he presented the analogy of a massive primordial atom that decayed into the matter that makes up the universe[xiv].  Lemaître suggested a sequence of events involving explosion, rapid expansion, coasting and the a further period of expansion[xv]. This was the first concise and considered ‘Big Bang’ model of the formation of the universe.  Like Friedman’s work, it was originally overlooked through a combination of limited circulation and closed minds in the astronomy community.  Because of Lemaître’s dual role as a priest, it was also dismissed as religious apology, seeking to tailor science to religious dogma[xvi].  Key problems for both Friedman and Lemaître were a lack of observational data to support their theories[xvii], although Lemaître utilized Hubble’s estimate of the universes age to provide a scale for his model (2.7¹⁰ parsecs[xviii]). Arthur Eddington, a major figure in astronomy beside Hubble, was supportive of Lemaître’s reasoning, but rejected his finite universe on philosophical grounds, favouring a slow-expansion universe, with an infinite timeframe for Lemaître’s primeval atom to “awaken from its slumber”[xix].  His book “The Expanding Universe” was the first popular treatment of the topic of the expanding universe[xx]. Although additional models – such as Milne’s “Kinematic relativity” which attributed observation to different galactic motions, and Zwicky’s gravitational stretching of light’s wavelength – were put forward, Hubble’s observations were generally felt to show the universe was expanding, and sides would be taken over whether this expansion occurred in a finite or infinite universe.

The Big Bang Emerges

“this “big bang” idea seemed to me to be unsatisfactory” - Fred Hoyle christens the Big Bang during a radio broadcast, despite has attempts at derision[xxi]. With the need to develop a model of the universe that incorporated the expansion shown by Hubble, the field of theoretical cosmology emerged.  George Gamow was one of the first to take up the cause.  Examining Lemaître’s radioactive primordial atom, Gamow believed such a model would produce a universe dominated by the stable middle elements, particularly iron.  This was at odds with the observed elemental abundances, which showed hydrogen and helium as making up 99.9 of the observed universe,  in a ratio of roughly 10:1.  Gamow instead proposed a primeval universe as “highly compressed, hot, neutron gas”[xxii].  The neutrons would provide the building blocks of elements, but expansion would ensure that no runaway collapse to heavier elements would occur. Gamow later changed direction in seeking a theory to explain these observed abundances, starting with the simplest element – hydrogen – as his building block. Gamow examined the work of Hans Bethe and Fritz Houtermans on stellar fusion, which saw hydrogen converted to helium in the cores of stars.  However, to achieve observed abundances of helium would require time scales many times greater (27 billion years[xxiii]) than the then proposed age of the universe.  Ruling out the stellar path to helium production, Gamow took the currently observed density/temperature relationship in the universe, and then reversed the time arrow to arrive at a smaller, hotter universe.  Using the very early conditions of the universe, and assuming an environment composed of sub-atomic particles (protons, electrons, neutrons) – which he referred to as ylem[xxiv] - Gamow attempted to calculate the nuclear reactions at various temperature points in the early universe.  To assist him in this task, he worked with PhD student Ralph Alpher, whose mathematical strengths complemented one of Gamow’s weaknesses[xxv].  Using recently declassified Manhattan Project data on nuclear capture cross-sections, they calculated hydrogen/helium ratios of 10:1, almost exactly matching observations.  Their findings were published in the (now) landmark paper “The Origin of Chemical Elements” in 1948.  As a linguistic joke, Hans Bethe’s name was included on the paper, and it became known as the Alpher, Bethe, Gamow theory, although Bethe had nothing to do with its development. Always bound to generate controversy, critics cited the ratio matching as simply coincidence (access to emerging computer technology would strengthen their case[xxvi]).  More disturbing was the issue of heavier elements.  Although Gamow initially proposed that additional neutron capture created heavier elements[xxvii], the lack of a stable isotope with an atomic number of 5 created a major hurdle, and as the ‘origin of the chemical elements’ was the paper’s foremost aim, this presented a significant problem with the Big Bang model. Alpher began collaborating with physicist Robert Herman, and they studied the expanding plasma universe (the early universe being too hot for electron capture) as the energy was spread over a greater volume (the charged particles being bathed in a sea of photons).  As the plasma cooled, the temperature eventually reached a point where atoms could form, and with their neutral electrical charge no longer interacting with the photons, the radiation was left permanently isolated.  Most importantly, they went on to predict that this light, which has been ‘frozen out’ at a wavelength of 10^-8 m (correlating to a temperature of 3000K[xxviii]) would today be stretched to millimeter lengths – thereby leaving a residue of radiation in the microwave band.  They predicted this background radiation would have a temperature of 5K[xxix] However, microwave detection was an underdeveloped field at this time, generating little academic interest, and a search for this background radiation was not viable.  Combined with a poor uptake of Big Bang theory, primarily because of its conflict with the predominant world view, Big Bang theory effectively stalled, awaiting observational evidence.  Gamow’s personality and reputation also saw his worked dismissed out of hand in some quarters.  Although convinced of the strength of their arguments, attempts to establish university based research centres focusing on Big Bang cosmology eventually petered out[xxx], and all three men would move on from cosmology before the matter was settled, and would play no major part in the further development of Big Bang. Two problems stood out for those supporting a Big Bang universe:

1. the age of the universe as derived from Hubble’s observations was less than half the age of the Earth as determined by a number of geological techniques,
2. there was no way to account for the synthesis of elements heavier than helium

Steady State Fights Back

“Modern astrophysics appear to be inexorably forcing us away from a universe of finite space and time, in which the future holds nothing… towards a universe in which both space and time are infinite.  The possibilities of physical evolution, and perhaps even of life, may well be without limit.  These are the issues that stand today before the astronomer.  Within a generation we hope that they can be settled with reasonable accuracy.”  A bullish Fred Hoyle at a meeting of the Edinburgh Royal Astronomical Society in 1948[xxxi]. British astronomer Fred Hoyle also had problems with the age of the universe predicted by Hubble, and matched with his philosophical objections to a finite universe, sought an alternate theory.  Collaborating with Thomas Gold and Hermann Bondi, they argued that an expanding universe did not imply a single point of creation.  Hoyle adopted the philosophy that “unchanging situations are still dynamic” – using a river as an analogy.  Gold proposed that new matter was created at a rate that balanced out the decline in density from expansion – a model they termed the ‘Steady State’ model. Such a model was consistent with the observations of Hubble and others.  Thus, as well as being isotropic and homogenous in space, the universe was homogenous in time – tagged the ‘perfect cosmological  principle’.  Thus, there was not only no preferred place in the universe, but no preferred time either[xxxii].  This was the major differentiating point for the Big Bang model, which stated that the universe was different over time. Bondi prepared a paper in 1947 summarising the field of knowledge in cosmology at that time, focusing on gaps in knowledge in the field, and he singled out evolution of galaxies over time as a major cosmological issue. Conservation of mass is a consequence of field theories within General Relativity.  Hoyle removed this requirement and reformatted the theories, adding continuous creation as a feature – the so called “Creation-Field” (C-Field).  This was nothing less than modification of General Relativity[xxxiii].  Hoyle then sought solutions for the field equations for a universe where average density remains constant.  Like Gamow’s initial universe, Hoyle believed that the matter created in the C-Fields would be sub-atomic, and favoured neutrons, which would decay to electrons and protons, upon which he believed would then form a hydrogen atom, consistent with observations of its vast abundance[xxxiv]. Bondi focused on the mathematical ramifications.  The creation of matter violated the known laws of physics, but galactic recession and subsequent red-shifting of light reduced energy, leaving the universe’s matter/energy content (as per E=MC²) constant[xxxv]. On of the key appeals of Steady State was that it gave permanency to physical laws – they aren’t ‘created’ at a point in time.  Steady State also agreed with Hubble’s results on galactic distribution[xxxvi], and the Gold-Bondi model fitted with General Relativity using observational data (rather than arbitrary inputs).  It was also consistent with distance galaxy counts[xxxvii]. Two papers were released in 1949 – the paper by Gold and Bondi took a more philosophical perspective, whilst Hoyle’s paper treated the theory in more mathematical detail.  Although possibly philosophically pleasing, the theory raised two major questions:

1. Where was the matter being created?
2. Where was the matter coming from?

Calculations on the density of created matter quickly answered question one – the observations of mass density only required one atom per cubic meter each million years[xxxviii] – an undetectable amount.  The second question could not be so easily dismissed, and ‘C-fields’ were the nominated mechanism.  However, there was no underlying physics to support this notion, and Hoyle was hoping that new discoveries would support a theory that assuaged most sensitivities.  This put him at odds with Gold and Bondi, who actually attacked C-Field theory in their paper, saying “In view of these objections we have no hesitation in rejecting Hoyle’s theory, although it is the first… formulation of the hypothesis of continuous creation of matter.”[xxxix]  By contrast, “[Hoyle] preferred the approach of the physicist: get the physical equations first and then derive the model to follow as a consequence of those equations.”[xl] These objections aside, Steady State theory should have left some observational evidence.  With new galaxies constantly being created, ‘baby galaxies’ should be everywhere.  Conversely, in an evolving universe, such galaxies should only be seen in the early stages of the universe, which from an observational perspective means very distant[xli].  However, at this point in the debate, telescopes were unable to resolve to this level of detail, and this lack of crucial evidence maintained the debate, and lead to some acrimony between protagonists.  Hoyle, Gold and Bondi lacked links to observational astronomy, and this was sometimes cited to weaken their case. Unlike most other astronomic debates, the Big Bang/Steady State debate was quite a public one, in part due to the celebrity status of the their two leading proponents – Gamow and Hoyle (who both wrote for a general audience), as well as an emerging interest in science by the general public and the growth of popular media (Hoyle became very famous (and controversial) in England for his radio broadcasts).  The extent to which this debate was public can be gauged by the Vatican’s decision to endorse Big Bang cosmology as consistent with Catholic theology.  This support, however, lead to some opponents of Big Bang to claim it was a stalking horse for religious dogma, and Lemaître asked the pope to refrain from commenting in future[xlii]. A lingering problem for the Big Bang model was the “time scale difficulty”, where the age of the universe was less than the age of the solar system.  Recessional velocity was a tricky technique, the required a number of deductive steps, each of which had its own scope for introducing errors.  This applied to almost all techniques.  Therefore, the age of the universe was an area subject to improvement on the back of technical and other advances in the field of observational astronomy.  However, there was little evidence for or against Steady State, and much of its appeal was philosophical. As well as previously mentioned issues, Big Bang also had additional problems, including the mechanism for forming galaxies, the breaking up of ‘baby’ galaxies during initial expansion, and the short timeframe allowed for galactic formation.  Steady State did not have to deal with the last one, having on infinite time span to form these structures. A poll by Science New Letter in 1959 of 33 scientists showed 11 supported Big Bang, 8 supported Steady State and 14 were undecided[xliii].  Primarily, the lack of supporting observational evidence lead many to go with the gut instincts – or what felt most comfortable with their personal beliefs. With the major work on both theories published before the early 50s, the state of play was as follows[xliv]:

As we can see, neither side is able to make a compelling case.  Both require further observational evidence, often dependant on technical advances.

Big Bang Gains the Ascendancy

“I had taken my cosmology from Hoyle at Caltech, and I very much liked the Steady State universe.  Philosophically, I still sort of like it.” – Robert Wilson, expressing some sorrow at possibly putting the final nail in the Steady State coffin[xlv]. The first problem with Big Bang to be overcome was the timescale difficulty.  Walter Baade, a German-American astronomer, was studying Cepheids in M31[xlvi], when he determined that stars existed in two broad classes, called Population I and Population II (based on the level of metallicity[xlvii]).  Cepheids in these classes exhibited different properties, with Population II being much brighter.  The Cepheids in M31 were Population II, but were being evaluated as though they were Population I, therefore leading to the belief that they were closer than they actually were.  Through rigorous measurement, Baade calculated that M31 was actually 2 million light years away[xlviii], double the previous extrapolated distance, and as it was the benchmark for measuring the distance to other galaxies, it effectively doubled the size of the universe.  This had the effect of halving the Hubble Constant, and doubling the age of the universe, to a figure that was more compatible with earth-based age estimations. Baade’s work did not provide a totally accurate scale (by it’s nature, such distance measurement will never be totally accurate), but certainly showed observational short-fallings where improvements could provide more accurate measures of the cosmological scale. Whilst Cepheids had been providing a ‘standard candle’ for nearby galaxies, they were insufficiently bright to be detected in more remote galaxies, and other methods were used.  One method involved measuring and comparing the brightest stars in galaxies – a rough, but statistically valid measure.  Discoveries by Allan Sandage of super heated clouds of hydrogen (known as HII regions) within galaxies, which were much brighter than the brightest stars, identified another misleading measuring stick, and allowances for HII clouds pushed the universe’s age out to 5.5 billion years (1954).  Subsequent advances, refinements and gathering of additional data by far more sensitive detectors (such as the Hubble telescope) have provided a date range of 10-20 billion years.  These advances have well and truly solved the ‘timescale problem’. Ironically, the next major step in the validation of the Big Bang theory came from the key supporter of Steady State, Fred Hoyle.  Moving on from cosmology[xlix], Hoyle began studying the fuel burning process in stars as outlined by Bethe and Houtermans.  Hoyle examined the likely scenario when a star had burnt most of its fuel.  Without the outward radiative pressure of nuclear fusion, the star would begin to contract gravitationally.  This contraction would increase density, and hence the star’s interval temperature.  Hoyle calculated that this would enable new fusion reactions to take place, creating heavier elements, all the way up to iron[l].  Once he overcame difficulties of carbon synthesis (teaming up with Willy Fowler), Hoyle was able to outline in detail the interval stellar processes that would produce heavier elements up to iron[li].  Hoyle also collaborated with Fowler and Geoffrey and Margaret Burbidge to investigate Big Bang Nucleosynthesis[lii], and they were able to account for Li⁸ and He³ abundances.  This is a further irony, with Hoyle investigating the operation of a theory he did not proscribe to.

More victories for the Big Bang

When initially promoting their Steady State model, Bondi would often remark “If the universe has ever been in a very different state from what it is now, show me some fossil remains of what it was like long ago!”[liii].  Such fossils were soon to emerge. Martin Ryle, a contemporary and rival of Hoyle’s (though not in the field of Big Bang versus Steady State) studied radio galaxies, high energy output in the radio spectrum, but low comparative optical output.  In 1961 he reached the conclusion that radio galaxies were more distant, implying they were a hallmark of a younger universe, but not the present.  This added further weight to the argument of a dynamic, evolving universe.  Hoyle’s attempts to discredit Ryle’s findings were the product of animosity between the two[liv], and marked Hoyle’s less open minded defense of Steady State theory.  The discovery of quasars – bright galaxies in the radio spectrum – was further evidence, as quasars by their distribution appeared to be early universe constructs.  These two pieces of radio evidence showing different structures at different ages directly assaulted the notion of the ‘perfect cosmological principle’, showing a universe that changed as it aged. The coup de grace for Big Bang theory was the famous work of Arno Penzias and Robert Wilson, who in seeking to maximize noise reduction in a radio antenna they had built, were unable to remove or account for a particular frequency that was omni-directional.  Around this time, Robert Dickie and James Peebles had, independently of Gamow and Alpher, predicted a background radiation in the microwave range (ascribing the now-familiar title of Cosmic Microwave Background radiation – CMB).  What Dickie and Peebles had predicted and were about to start searching for, Penzias and Wilson had discovered.  A pair of papers were published in 1965, with Penzias and Wilson offering a simple description of their processes and results, with Dickie and Peebles detailing how this observation was the CMB they had predicted[lv]. This was probably the major telling point in the debate, as Big Bang directly predicted CMB, whilst Steady State had no way of accounting for it.

Debate over?

“To claim, however, as many supporters of Big Bang cosmology do, to have arrived at the correct theory verges, it seems to me, an arrogance.” – Fred Hoyle[lvi] Let us revisit our debate ‘scorecard’, using the state of knowledge as at 1978[lvii]:

At this point it seemed that debate had been won – with the Big Bang model being able to account for almost all aspects of the observed universe.  Apart from philosophical considerations about a universe with a finite start, the only aspect of Big Bang theory that was not readily reconcilable with observations was the formation of galactic structures.  Whilst the discovery of CMB had been a strong predictive success for Big Bang, its extreme homogeneity made it difficult to ascribe a mechanism for galactic formation, which were clearly localized non-homogenous regions. Tests from high altitude planes and balloons in the 1970’s failed to discern any fluctuations in the CMB radiation, to an accuracy of 1:1000[lviii].  It wasn’t until the COBE satellite launch in 1989, and a successive set of sweeps at greater magnifications that fluctuations were finally found at variations on 30 millionths of a degree[lix] (see Figure 2).  This map represents a view of the universe when ‘recombination’ (electrons and protons forming atoms) occurred, about 300,000 years after the Big Bang.  Although the topic of galactic structure formation is still highly debated, the COBE data showed that variations did exist, allowing localised differences in matter density to occur.  WMAP[lx] data has provided greater resolution, but for the purposes of the debate, simply reinforces the COBE results. Figure 2. CMB anisotropy formed from data taken by the COBE spacecraft[lxi]

Current State of Play

Like most scientific theories that gain ascendancy, the Big Bang still has a number of specific problems and issues to be addressed.  The formation of galactic structures has been touched upon, but other issues relating to the Big Bang include:

• its impact on the geometry of the universe (open, close, flat)
• the nature and role of dark matter
• the role of inflation in the universe’s development
• the unification of forces in the very early universe
• matter/anti-matter asymmetry

These are more focused on the processes taking place within the Big Bang, rather than the question of whether the Big Bang actually occurred, and outstanding issues in this area do not undermine the strong case for the Big Bang as a description of the universe’s formation. Despite a wealth of supporting evidence, Hoyle and Gold refused to let go of Steady State theory (Hermann had by this stage defected), and in collaboration with Jayant Narlikar and Geoffrey Bambidge, Hoyle produced quasi-Steady State theory in the 1990’s.  This was an attempt to reconcile some of the supportive arguments for Big Bang cosmology with the overlying philosophy of Steady State.  Its features include[lxii]:

• regular contraction phases in between longer expansion phases
• matter creation in bursts within the strong gravitational fields of galactic centres
• massive Planck particles as the initial state of created matter, rapidly decaying into more mundane matter
• challenging the CMB support for Big Bang[lxiii]

Despite some highly creative suggestions and supporting arguments, quasi-Steady State was not taken very seriously by the scientific establishment, and appeared as Hoyle and his collaborators refusing to let go of their beloved infinite universe.

Conclusion

Like most significant debates in astronomy, the initial clash of Big Bang cosmology and the Steady State model grew out of a lack of observational evidence to decidedly favour either of two competing theories that both matched available data.  And as with most successfully resolved debates, advances in astronomy, both incremental (improved observational instruments) and sudden (discovery of quasars and CMB) filled the gaps in one theory’s supporting arguments, whilst further marginalising the other.  The successes of new discoveries addressing the Big Bang model’s issues were particularly dramatic, and allowed Big Bang cosmology to become the most likely description of the formation of the universe.  Likewise, it consigned Steady State theory to the pile of elegant, yet unsupported theories that help propel our knowledge forward.

Bibliography

Arnett, D. “Supernovae and Nucleosynthesis.  An investigation of the History of Matter, from the Big Bang to the Present”, PrincetonUniversity Press, 1996 Ellis, G. “Before the Beginning”, Bowerdean Publishing, 1993 Farrell, J. “The Day Without Yesterday – Lemaitre, Einstein and the birth of Modern Cosmology”, Thunder’s Mouth Press, 2005 Gribbin, J, “In the Beginning”, Viking, 1993 Hawking, S. “The Theory of Everything”, New Millennium Press, 2002 Kragh, H. “Cosmology and Controversy”, PrincetonUniversity Press, 1996 Mitton, S. “Fred Hoyle.  A Life in Science”, Aurum Press, 2005 Schilling, G. “Evolving Cosmos”, CambridgeUniversity Press, 2004 Singh, S. “Big Bang”, Forth Estate, 2004

[i] Singh p.147 [ii] An infinite universe could theoretically address this issue, but would need to be incredibly finely balanced to prevent localized collapse.  Other issues, such as Olber’s paradox also discouraged this notion. [iii] Singh p.148 [iv] Although initially dismissing both Friedman and Lemaître, Einstein later ‘recanted’, and described the cosmological constant as his ‘greatest blunder’. [v] Mitton p.110 [vi] Singh p.152 [vii] Farrell, p.11 [viii] Which had been debated without conclusion by Shapely and Carter [ix] Some nearby galaxies are gravitationally attracted to the Milky Way, and exhibit a blue-shift.  This is a phenomenon limited to a handful of local galaxies. [x] Technically, the red-shifts are the stretching of space-time, rather than galactic recession [xi] The fossil record and the long time frames required for Darwinian evolution [xii] http://www.astro.ucla.edu/~wright/cosmo_01.htm [xiii] Singh p. 158 [xiv] He further proposed that the energy that was released from this decay powered the expansion of the universe [xv] Mitton p. 111 [xvi] Singh p. 158 [xvii] Singh p.161 [xviii] Farrell, p90. [xix][xix] Mitton p.111 [xx] http://www.cambridge.org/catalogue/catalogue.asp?isbn=0521349761 [xxi] http://kwc.org/blog/archives/2005/2005-01-31.talk_simon_singh_the_big_bang.html [xxii] Singh p.314 [xxiii] Singh p.310 [xxiv] An obsolete noun meaning “the primordial substance from which the elements were formed”- Kragh p.114 [xxv] Singh p.315 [xxvi] Singh .326 [xxvii] Kragh, p. 111 [xxviii] Ellis, p 53 [xxix] Kragh, p. 132 [xxx] Kragh p. 138 [xxxi] Mitton p. 124 [xxxii] Mitton p.120 [xxxiii] Mitton p.119 [xxxiv] Mitton p.119 [xxxv] Mitton p.118 [xxxvi] Mitton p.120 [xxxvii] Mitton p.120 [xxxviii] Mitton p.120 [xxxix] Mitton p.121 [xl] Mitton p.121 [xli] As limited by the speed of light [xlii] Singh p.362 [xliii] Singh p.364 [xliv] Singh p.370-371 – reproduced in full [xlv] Singh, p.432 [xlvi] Actually, his initial search was for RR Lyrae stars, but these were too faint to be seen [xlvii] which in turn is a product of the degree to which stars are composed of the debris of other stars [xlviii] Singh p.377 [xlix] Actually, Hoyle’s work does not follow a compartmentalized time line [l] Not all irons lighter than iron but heavier than helium are produced in this way e.g. lithium [li] Beyond iron, supernovae are responsible for element production [lii] Producing the famous “Synthesis of the Elements of Stars” paper [liii] Mitton p.123 [liv] Mitton p.167 [lv] Singh p.432 [lvi] Singh p.483 [lvii] Singh p.444-445 – reproduced in full [lviii] Singh p.451 [lix] Gribbin, p.40 [lx] Wilkinson Microwave Anisotropy Probe – producing data since 2003 [lxi] http://en.wikipedia.org/wiki/COBE [lxii] Mitton p.314 [lxiii] Mitton p.314