The larger a star, the hotter its core gets, and the faster it burns up its nuclear fuel. If the largest stars, many times heavier than the Sun, tended to form in the earlier stages of the formation of our galaxy, they would long ago have gone through their burning phase, producing large amounts of helium, and then exploded as supernovas. Both in Lerner's theoretical models and Peratt's simulations, the stars forming along the spiral arms as they swept through the plasma medium would become smaller as the density of the medium increased. As the galaxy contracted, larger stars would form first, and smaller, longer-lived ones later. The smaller, more sedate stars—four to ten times larger than the Sun—would collapse less catastrophically at the end of the burning phase, blowing off the outer layers where the helium had been formed initially, but not the deeper layers where heavier elements would be trapped. Hence the general abundance of helium would be augmented to a larger degree than of the elements following it; there is no need for a Big Bang to have produced all the helium in a primordial binge.
Critics have argued that this wouldn't account for the presence of light elements beyond helium such as lithium and boron, which would be consumed in the stellar reactions. But it seems stars aren't needed for this anyway. In June 2000, a team of astronomers from the Universities of Austin, Texas, and Toledo, Ohio, using the Hubble Space Telescope and the McDonald Observatory, described a process they termed "cosmic-ray spallation," in which energetic cosmic rays consisting mainly of protons traveling near the speed of light break apart nuclei of elements like carbon in interstellar space. The team believed this to be the most important source of the lighter elements. 55
And of Producing Expansion
That pretty much leaves only the original Hubble redshift as the basis for the Big Bang. But as we've already seen, the steady-state theory proposed another way in which it could be explained. And back in the early sixties, Alfvén gave some consideration to another.
A theory put forward by an old colleague and teacher of his, Oskar Kleine, had proposed antimatter as the energy source responsible. Antimatter had been predicted from quantum mechanics in the 1920s, and its existence subsequently confirmed in particle experiments. For every type of elementary particle, there also exists an "antiparticle," identical in all properties except for carrying the opposite electrical charge (assuming the particle is charged). If a particle and its antiparticle meet, they annihilate each other and are converted into two gamma rays equal in energy to the total masses of the particles that created them, plus the kinetic energy they were carrying. (The thermonuclear reaction in a hydrogen bomb converts about one percent of the reacting mass to energy.) Conversely, sufficiently energetic radiation can be converted into particles. When this occurs, it always produces a particle-antiparticle pair, never one of either kind on its own.
This fact leads to the supposition that the universe too ought to consist of equal amounts of both particles and antiparticles. Kleine hypothesized that in falling together under gravity, a particle-antiparticle mixture (too rarified to undergo more than occasional annihilating collisions) would separate according to mass; at the same time, if the motion were in a magnetic field, positive charges would be steered one way and negative charges the other. The result would be to produce zones where either matter or antimatter dominated, with a layer of energetic reactions separating them and tending to keep them apart while they condensed into regions of galaxies, stars, and planets formed either from ordinary matter, as in our own locality, or of antimatter elsewhere.
Should such matter and antimatter regions later meet, the result would be annihilation on a colossal scale, producing energy enough, Kleine conjectured, to drive the kind of expansion that the redshift indicated. This would make it a "Neighborhood Bang" rather than the Bang, producing a localized expansion of the part of the universe we see which would be just part of a far vaster total universe that had existed for long before. Although this allows time for the formation of large structures, there are questions as to how they could have been accelerated to the degree they apparently have without being disrupted, and others that require a lot more observational data, and so the idea remains largely speculative.
Redshift Without Expansion at All
Molecular Hydrogen: The Invisible Energy-Absorber
The steady-state and Kleine's antimatter theories both accepted the conventional interpretation of the redshift but sought causes for it other than the Big Bang. But what if it has nothing to do with expansion of the universe at all? We already saw that Finlay-Freundlich's derivation of the background temperature in the early fifties considered a "tired light" explanation that Born analyzed in terms of photon-photon interactions. More recently, the concept has found a more substantial grounding in the work of Paul Marmet, a former physicist at the University of Ottawa, and before that, senior researcher at the Herzberg Institute of Astrophysics of the National Research Council of Canada.
It has long been known that space is permeated by hydrogen, readily detectable by its 21-centimeter emission line, or absorption at that wavelength from the background radiation. This signal arises from the spin of the hydrogen atom. Monatomic hydrogen, however, is extremely unstable and reacts promptly to form diatomic hydrogen molecules, H2. Molecular hydrogen is very stable, and once formed does not easily dissociate again. Hence, if space is pervaded by large amounts of atomic hydrogen, then molecular hydrogen should exist there too—according to the calculations of Marmet and his colleagues, building up to far greater amounts than the atomic kind. 56 Molecular hydrogen, however, is extraordinarily difficult to detect—in fact, it is the most transparent of diatomic molecules. But in what seems a peculiar omission, estimates of the amount of hydrogen in the universe have traditionally failed to distinguish between the two kinds and reported only the immediately detectable atomic variety.
Using the European Space Agency's Infrared Space Observatory, E. A. Valentijn and P. P. van der Werf recently confirmed the existence of huge amounts of molecular hydrogen in NGC891, a galaxy seen edge-on, 30 million light-years away. 57 This discovery was based on new techniques capable of detecting the radiation from rotational state transitions that occur in hydrogen molecules excited to relatively hot conditions. Cold molecular hydrogen is still undetectable, but predictions from observed data put it at five to fifteen times the amount of atomic hydrogen that has long been confirmed. This amount of hitherto invisible hydrogen in the universe would have a crucial effect on the behavior of light passing through it.
Most people having a familiarity with physics have seen the demonstration of momentum transfer performed with two pendulums, each consisting of a rod weighted by a ball, suspended adjacently such that when both are at rest the balls just touch. When one pendulum is moved away and released, it stops dead on striking the other, which absorbs the momentum and flies away in the same direction as the first was moving. The collision is never perfectly "elastic," meaning that some of the impact energy is lost as heat, and the return swing of the second pendulum will not quite reverse the process totally, bringing the system eventually to rest.
Something similar happens when a photon of light collides with a molecule of a transparent medium. The energy is absorbed and reemitted in the same, forward direction, but with a slight energy loss—about 10-13 of the energy of the incoming photon. 58 (Note this is not the same as the transverse "Rayleigh scattering" that produces angular dispersion and produces the blueness of the sky, which is far less frequent. The refractive index of a transparent medium is a measure of light's being slowed down by successive forward re-emissions. In the case of air it is 1.0003, indicating that photons traveling 100 meters are delayed 3 centimeters, corresponding to about a billion collisions. But there is no noticeable fuzziness in images at such distances.)
What this means is that light traveling across thousands, or millions, or billions of light-years of space experiences innumerable such collisions, losing a small fraction of its energy at each one and hence undergoing a minute redde
ning. The spectrum of the light will thus be shifted progressively toward the red by an amount that increases with distance—a result indistinguishable from the distance relationship derived from an assumed Doppler effect. So no expansion of the universe is inferred, and hence there's no call for any Big Bang to have caused it.
Two further observations that have been known for a long time lend support to this interpretation. The Sun has a redshift not attributable to gravity, which is greater at the edges of the disk than in the center. This could be explained by sunlight from the edge having to pass through a greater thickness of lower solar atmosphere, where more electrons are concentrated. (It's the electrons in H2 molecules that do the absorbing and reemitting.) Second, it has been known since 1911 that the spectra of hot, bright blue OB-type stars—blue-white stars at the hot end of the range that stars come in—in our galaxy show a slight but significant redshift. No satisfactory explanation has ever been agreed. But it was not concluded that we are located in the center of an expanding shell of OB stars.
So the redshift doesn't have to imply an expansion of the universe. An infinite, static universe is compatible with other interpretations—and ones, at that, based on solid bodies of observational data rather than deduction from assumptions. However, none of the models we've looked at so far questions the original Hubble relationship relating the amount of the shift to distance (although the value of the number relating it has been reappraised several times). But what if the redshifts are not indicators of distance at all?
The Ultimate Heresy:
Questioning the Hubble Law
The completely revolutionary threat to toppling the last of Big Bang's supporting pillars came not from outside mavericks or the fringes, but from among the respected ranks of the professionals. And from its reactions, it seems that the Establishment reserves its most savage ire for insiders who dare to question the received dogma by putting observation before theory and seeing the obvious when it's what the facts seem to say.
Halton Arp's Quasar Counts
Halton Arp comes from a background of being one of America's most respected and productive observational astronomers, an old hand at the world-famous observatories in California and a familiar face at international conferences. Arp's Atlas of Peculiar Galaxies has become a standard reference source. Then, in the 1960s and '70s, "Chip" started finding excess densities of high-redshift quasars concentrated around low-redshift galaxies.
A large redshift is supposed to mean that an object is receding rapidly away from us; the larger the shift, the greater the recession velocity and the distance. With the largest shifts ever measured, quasars are by this reckoning the most distant objects known, located billions of light-years away. A galaxy showing a moderate shift might be thousands or millions of times less. But the recurring pattern of quasars lying conspicuously close to certain kinds of bright galaxies suggested some kind of association between them. Of course, chance alignments of background objects are bound to happen from time to time in a sky containing millions of galaxies. However, calculating how frequently they should occur was a routine statistical exercise, and what Arp was saying was that they were being found in significantly greater numbers than chance could account for. In other words, these objects were associated in some kind of way. A consistently recurring pattern was that the quasars appeared as pairs straddling a galaxy.
The first reactions from the orthodoxy were simply to reject the observations as being incorrect—because they had to be. Then a theoretician named Claude Canizares suggested an explanation whereby the foreground galaxy acted as a "gravitational lens," magnifying and displacing the apparent position of a background quasar. According to Einstein's theory, light rays passing close to a massive body will be bent by its gravity (although, as discussed later in the section on relativity, other interpretations see it as regular optical refraction). So imagine a massive foreground galaxy perfectly aligned with a distant quasar as viewed from Earth. As envisaged by the lensing explanation, light from the quasar that would otherwise pass by around the galaxy is pulled inward into a cone—just like light passing through a convex optical lens—and focused in our vicinity. Viewed back along the line of sight, it would be seen ideally as a magnified ring of light surrounding the galaxy. Less than ideal conditions would yield just pieces of the ring, and where these happened to be diametrically opposed they would create the illusion of two quasars straddling the intervening galaxy. In other cases, where the alignment is less than perfect, the ring becomes a segment of arc to some greater or lesser degree, offset to one side—maybe just a point. So quasar images are found close to galaxies in the sky more often than you'd expect.
But the locations didn't match fragmented parts of rings. So it became "microlensing" by small objects such as stars and even planets within galaxies. But for that to work, either the number of background quasars would need to increase sharply with faintness, whereas actual counts showed the number flattening off as they got fainter. Such a detail might sound trivial to the lay public, but it's the kind of thing that can have immense repercussions within specialist circles. When Arp submitted this fact to Astronomy and Astrophysics the editor refused to believe it until it was substantiated by an acknowledged lens theorist. When Arp complied with that condition, he was then challenged for his prediction as to how the counts of quasars should vary as a function of their apparent brightness. By this time Arp was becoming sure that regardless of the wrecking ball it would send through the whole cosmological edifice, the association was a real, physical one, and so the answer was pretty easy. If the quasars were associated with bright, nearby galaxies, they would be distributed in space the same way. And the fit between the curves showing quasar counts by apparent magnitude and luminous Sb spiral galaxies such as M31 and M81—galaxies resembling our own—was extraordinarily close, matching even the humps and minor nonlinearities. 59
Arp's paper detailing all this, giving five independent reasons why gravitational lensing could not account for the results and demonstrating that only physical association with the galaxies could explain the quasar counts, was published in 1990. 60 It should have been decisive. But four years later, papers were still reporting statistical associations of quasars with "foreground" galaxy clusters. Arp quotes the authors of one as stating, "We interpret this observation as being due to the statistical gravitational lensing of background QSO's [Quasi-Stellar Objects, i.e., quasars] by galaxy clusters. However, this . . . overdensity . . . cannot be accounted for in any cluster lensing model . . ." 61
You figure it out. The first part is obligatory, required by custom; the second part is unavoidable, demanded by the data. So I suppose the only answer is to acknowledge both with an Orwellian capacity to hold two contradictory statements and believe both of them. Arp's paper conclusively disproving lensing was not even referenced. Arp comments wearily, "As papers multiply exponentially one wonders whether the end of communication is near."
Taking on an Established Church
It's probably worth restating just what's at stake here. The whole modern-day picture of extragalactic astronomy has been built around the key assumption that the redshifts are Doppler effects and indicate recessional velocity. Since 1929, when Edwin Hubble formulated the law that redshift increases proportionally with distance, redshift has been the key to interpreting the size of the universe as well as being the prime evidence indicating it to be expanding from an initially compact object. If the redshifts have been misunderstood, then inferred distances can be wrong by a factor of from 10 to 100, and luminosities and masses wrong by factors up to 10,000. The founding premise to an academic, political, and social institution that has stood for three generations would be not just in error but catastrophically misconceived. It's not difficult to see why, to many, such a possibility would be literally inconceivable. As inconceivable as the thought once was that Ptolemy could have been wrong.
It began when Arp was studying the evolution of galaxies and found a consistent pattern showi
ng pairs of radio sources sitting astride energetic, disturbed galaxies. It seemed that the sources had been ejected from the galaxies, and the ejection had caused the disturbance. This was in line with accepted thinking, for it had been acknowledged since 1948 that galaxies eject radio-emitting material in opposite directions. Then came the shock that time and time again the sources turned out to be quasars, often showing other attributes of matter in an excited state, such as X-ray emissions and optical emission lines of highly energized atoms. And the galaxies they appeared to have been ejected from were not vastly distant from our own, but close by.
These associations had been accumulating since the late sixties, but in that time another kind of pattern made itself known also. A small group of Arp's less conformist colleagues, who even if perhaps not sharing his convictions totally, remained sufficiently open-minded to be sympathetic. From time to time one of them would present observational data showing another pair of radio or X-ray sources straddling a relatively nearby low-redshift galaxy which coincided with the optical images of Blue Stellar Objects—quasar candidates. To confirm that they were quasars required allocation of observation time to check their spectra for extreme quasar redshifts. At that point a dance of evasion would begin of refusals to look through the telescopes—literally. The requests would be turned down or ignored, even when they came from such figures as the director of the X-Ray Institute. When resourceful observers cut corners and made their own arrangements, and their findings were eventually submitted for publication, hostile referees would mount delaying tactics in the form of finicky fussing over detail or petty objections that could hold things up for years.
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