Part Two: The Big Bang
In the midst of the continuing progress of the 19th century, an increasing reliance on theoretical science began to separate the Earth from the heavens once again. This time, though, something of the scale of the observable universe was known, and the problem of finding out where so much matter and energy came from became even greater.
In 1917, Albert Einstein assumed that the universe, on the largest possible scale, is homogenous, despite overwhelming evidence that the universe appears clumpy on all scales. This assumption of homogeneity carried on to all relativistic cosmology. Einstein's finite, static universe of 1917, only 18 million light years across, was unstable; gravity should have collapsed it. So Einstein introduced "the cosmological constant", an arbitrary repulsive force that he gave just enough strength to balance gravity. Unfortunately, that led to the situation where the slightest expansion or contraction would cause the universe to expand into a heat death or collapse into a "big crunch" (p. 131).
Then, In 1924, Carl Wirtz noticed that a galaxy's redshift increases as its apparent brightness decreases. (The pattern of lines in an object's spectrum is shifted to the red, low-energy end.) He made the tentative assumption that the dimmer galaxies were farther away, and used an analogy to the Doppler effect to propose that stars with greater redshifts are moving away from us at greater speeds. Meanwhile, Edwin Hubble had measured distance to galaxies using the known brightness of stars called Cepheid variables. Hubble's data confirmed the relation between redshift and distance, hence the "Hubble redshift" (p. 132).
The first hint of a big bang came in 1931, when Georges-Henri Lemaître published his "primeval atom" theory. Using Ludwig Bolzmann's 1877 arguments about entropy and heat death (all energy decays into heat), re-espoused by Sir James Jeans in 1928, he argued that an increase in entropy means an increase in the number of particles in the universe. Therefore, in the beginning, the universe must have consisted of one infinitely small particle containing all the mass in the universe, which split into less and less massive particles, just as a radioactive nucleus decays into new elements until it reaches a stable state. He called it the "fireworks theory of cosmology". He justified it with one piece of evidence, the assumption that since cosmic rays could not be produced on a body with an atmosphere (they could not escape it), they must have been produced by the decay of the primeval atom. It was later shown that processes such as the fusion of hydrogen into helium could produce cosmic rays, and that most cosmic rays observed originated in our galaxy, and only appeared to be isotropic because they were scattered by magnetic fields (pp. 134-138).
The Big Bang was born during World War II. When scientists examined the fallout from early atom bomb tests, they found that the explosion had created new elements and isotopes. George Gamow, of the Manhattan Project, theorized that the original creation of the elements happened the same way. Gamow used mathematics to predict that the abundance of an element decreased exponentially as its atomic weight increased. Unfortunately, his prediction that elements such as carbon would be a trillion times less abundant than hydrogen was off by about ten billion. Gamow adjusted his calculations to account for the rapid cooling of the universe after the primeval explosion, then jury-rigged his early universe's density until it gave him the right concentration of heavy elements (pp. 140-141).
One thing yet to be explained was the cause of the big bang. Gamow theorized that an earlier universe had contracted, then bounced out into a new one. But observations in the fifties showed that the universe was expanding fast enough that it would overcome its gravitational attraction. The situation made Gamow's hypothesis analogous to that of a ball that bounces higher than the height from which it is dropped (pp. 142-143).
The Big Bang's domain as exclusive creator of heavy elements was questioned in 1946 when Fred Hoyle developed a model for stellar evolution that showed that when a star's core ran out of hydrogen, it would collapse to the point at which it was hot enough to fuse helium, then carbon, then oxygen, and so on. Hoyle's model produced elements in proportions close to those observed in the universe. Additional element-production by a big bang would result in too much of the heavy elements (pp. 143-144).
By 1948, Hoyle and two collaborators, Thomas Gold and H. Bondi, had thrown out the big bang in favor of a Steady State theory, in which the universe looks the same to an observer at any place or time. Unfortunately, this conflicted with the universal expansion demonstrated by the Hubble redshift. To account for the expansion, Bondi and Gold theorized that matter was being spontaneously created in the expanding gaps at a rate of one hydrogen atom per year in a space a hundred meters on a side. Their hypothesis was baseless, but conveniently, it could not be disproved; with trillions of atoms in even the remotest hundred meter wide block of space, it would be impossible to detect the creation of one atom per year (pp. 144-145).
In 1957 Hoyle and his colleagues published a paper showing how the most common elements lighter than iron could be produced by fusion. Iron is the most stable nucleus, so fusion cannot create heavier elements. When a massive star has fused all it can, it collapses, and its unburned outer layers suddenly mix in the extreme heat of contraction. The resulting rapid fusion causes a supernova, which crams more neutrons into the nuclei of the stellar material as it is hurled outward, creating the heaviest elements. Unfortunately, the theory did not account for the existence of certain light elements that are quickly burned in stars, or for the abundance of helium (p. 147).
In 1961, radioastronomy dealt a blow to the Steady State, as astronomers discovered that radio-emitting objects were more abundant in the far reaches of the universe. This conflicted with the necessary homogeneity of the Steady State (p. 148).
The discovery of quasars in 1964 lent new support to the Big Bang. Quasars look like ordinary stars, but their high redshifts suggest that they are very far away, and therefore very luminous, as much as a hundred times more luminous than a galaxy. Moreover, their light varies over periods of less than a year, meaning they can be no more than a light year across. Hoyle theorized that the collapse of an object a million times more massive than the Sun would liberate the energy observed in a quasar if it collapsed down to a single, geometric point—a singularity. The possibility that an object could collapse into such a singularity lent credence to the idea that the universe may have begun as one (pp. 148-149).
Still, the Big Bang's energy source was in question. Gamow used the universe's present energy density, and the fact that looking through space means looking back in time, to determine that the temperature of energy emitted from the big bang, observed today, would be 20K (20 Kelvin, or 20 above absolute zero). P.J.E. Peebles, dealing with the problem of the abundance of helium, later theorized that a certain ratio of photons per nucleus in the early universe would result in the observed quantity of helium. The energy released in his calculations would lead to a "background radiation" of 30K. By 1965, this background radiation had already been discovered by two scientists working for Bell Labs. The observed temperature, though, was 3.5K, leading to a serious problem: the amount of energy in a radiation field is proportional to its temperature to the fourth power. The radiation was several thousand times less powerful than Peebles or Gamow had predicted. This low temperature suggested that the universe was much less dense than the group had hoped; there was not enough gravity for a closed universe (pp. 150-151). This meant that the present universe could not have rebounded from a previous one.
A year later, Fred Hoyle used one parameter, the ratio of photons to protons, and one observation, the microwave background, to account for the abundance of three light elements and to predict the density of matter in the universe, leading to the golden age of the Big Bang (p. 153). It never did conform to the vast majority of observational evidence, but it rested on a firm foundation of pure mathematics. In fact, the Big Bangers were so confident in their calculations that, by the mid 1970s, cosmologists were describing the first hundredth of a second of creation in intimate detail, even though they could not agree when it occurred to within five billion years!
Many problems remained. According to the theory, galaxies, which take billions of years to form, must have evolved from clumps of matter in the early universe. But if these clumps existed, they should have left irregularities in the microwave background. When the results of the Cosmic Background Explorer (COBE) mission were announced in 1990, they showed no variation from a black body curve (p. 30).
Another problem was the low value of a parameter called "omega". Derived from a ratio, a value of omega = 1 is required to stop the expansion of the universe. But the universe has only a fraction of the amount of matter required for an Omega of 1. To create omega = 1, and to account for the ability of matter to clump into galaxies and clusters in the 15-20 billion years since the Big Bang, cosmologists decided that 99% of the universe exists as dark matter. Alan Guth, a particle physicist, used an artificial construct called the Higgs field to theorize that, for the first 10^-33 seconds of its existence, the universe doubled in size every 10^-35 seconds, then slowed down to the more sedate pace of the speed of light. The Higgs field also creates energy from nothing, justifying the existence of dark matter. Omega became 1 because scientists willed it, even though the best observations showed it to be around 0.02. Particle physicists theorized particles such as axions, WIMPs (Weakly Interacting Massive Particles), and photinos to explain the nature of dark matter. There was no evidence for their existence; they were deduced from Grand Unified Theories, or GUTs (pp. 32-34, 158-161).
Evidence for the existence of dark matter came from the observation of the motion of galaxies and galactic clusters. Assuming that gravity is the only force that holds a cluster together, they appear to be moving too rapidly to stay together. This was only enough to bring Omega up to 0.1, but it gave the Big Bangers hope (p. 35).
In 1984 this evidence was refuted. Mauri Valtonen and Gene Byrd found that the earlier studies had included "interlopers", galaxies in front or behind clusters, but not part of them. Removal of the interlopers revealed a lower mass for the clusters. Their computer simulations also found that some galaxies might be thrown out of the cluster by massive elliptical galaxies, the same principle as throwing a rock from a sling. If escaping galaxies were included in the earlier calculations, the cluster's mass would appear too high. Byrd and Valtonen's corrections accounted for all the missing mass. They eliminate any evidence for dark matter, and any possibility that objects as large as galaxies could have formed in a Big Bang universe as young as ours is supposed to be (pp. 36-39).
More recently, Hubble telescope observations have shown the maximum age of a Big Bang universe to be between 8 and 12 billion years. Other scientists argue for a calculated age of up to 14 billion years, but that still leaves a problem: Ordinary physics tells us that the oldest stars in our galaxy are at between 14 and 20 billion years old, leading to the conclusion that the universe is younger than the stars in it (Discover, pp. 68-72).
Perhaps the final nail in the Big Bang's well-sealed coffin comes from the latest attempt to find cosmic convergence, the idea that at a large enough scale, relative motions of galaxies and clusters are negligible compared to the motion of universal expansion. In the mid 1980s this concept was in trouble from the discovery of the Great Attractor. A group of scientists found that all the galaxies in a volume of space 100 to 200 million light years across were moving together toward one point in the sky.
In 1989, Tod Laurer and Marc Postman began Project Warpfire, the latest attempt to find cosmic convergence. They sought to use the cosmic microwave background (CMB) as a stationary reference point against which to measure the motion of the Earth relative to distant galaxies. This would cancel out the Earth's motion and allow for an accurate determination of the expansion speed of the universe. The motion of a galactic cluster as a whole (except for those moving toward the Great Attractor) should be stationary relative to the background. If we look at the cosmic background, we see a tiny blue shift in one direction, which corresponds to the Earth's motion through space (its compound motion around the sun, the sun's proper motion, etc.).
Scientists have found that the brightest galaxy in a cluster tends to be of a certain luminosity. Therefore, the distance to these galaxies can be determined with some accuracy. Laurer and Postman measured the motion of the Earth compared to 119 galaxies, each the brightest in a distant cluster, spread throughout the sky to a distance of 600 million light years. They found that the Earth and every galaxy they observed were moving at about 435 miles per second relative to the CMB, heading off to a point somewhere beyond Orion (Discover, pp. 72-74). It appears that, at all scales, the universe is moving at great speed with respect to the supposed expansion.
Yet another piece of evidence has been added as of April 1997. The Big Bangers, relentlessly insisting on some sort of homogeneity, insist that the universe can have no overall orientation—there should be nothing to which such orientation could be relative. A recent radio-frequency survey has proven otherwise. Scientists recently completed a massive survey of many galaxies spread throughout the universe, and found that all share a common magnetic orientation—the universe has a north pole!
Thus the Big Bangers would have us believe that we live in a universe that is younger than the stars in it, in which 99% of all matter is invisible, a universe that was created from nothing in a cataclysmic explosion, in a mess of exotic particles that changed the laws of physics until they were no longer required, then disappeared, a universe that cannot contain any structures larger than a billion light years across—when objects seven billion light years across have been observed. There is only one conclusion: The Big Bang Never Happened!
So what did happen?