Creation According to Cosmology
Cosmology, the study of the origin and evolution of the universe, deals with the largest questions which can be asked by science. Until very recently, attempts to deal with these questions have relied more on metaphysical preference than on physical principles, but since the middle 1960′s a consistent theory of the origin of the universe has become widely accepted, which relies on much the same combination of theoretical considerations and experimental evidence as do standard physical theories of more easily observed phenomena.
A description of the development of this standard cosmological picture of the birth of the universe is presented by Steven Weinberg in his book, The First Three Minutes.1 Weinberg, Higgins Professor of Physics at Harvard and one of the most distinguished of the younger generation of American physicists, shows how experimental observations made since 1965 have led to almost universal agreement among astrophysicists that the universe we inhabit had a unique instant of creation, and that it is possible, using well accepted principles of high-energy nuclear physics and statistical mechanics, to describe in considerable detail how the universe evolved from that instant on.
Perhaps of even more interest to the audience addressed by Weinberg, which is assumed to have only a lay knowledge of science but a considerable degree of intellectual sophistication, is his discussion of how the theory, basically worked out in the 1940′s and the subject of much controversy, was finally confirmed by observation twenty years later, in far from textbook fashion, with theorists not realizing that their predictions were actually capable of observation, and experimentalists not realizing what they were capable of observing and had, in fact, observed.
In the 1920′s Edwin Hubble discovered that the universe was expanding. When we look out in space, we look back in time. Thus, observation of distant stars and galaxies shows us how the universe appeared in the distant past. This is not all, however: the universe as a whole is also cooling as it expands. In times past, then, the universe was both more condensed and hotter than it is now.
In order to study how the universe evolved, it is necessary to reverse the expansion process. When this exercise is performed, it is found that the expansion had a unique starting point in time, where the density and temperature increased beyond limit. Present-day physics is unable to deal with such singular conditions, but it can give a very good account of events starting at only one-hundredth of a second after the beginning.
What happened in the few minutes succeeding this event is depicted in Weinberg’s book. He discusses only in general terms the process of the creation of stars and other objects familiar to the universe we know. But the curious reader can follow the story of stellar evolution, which basically encompasses the history of the universe after “the first three minutes,” in another recent book, The Collapsing Universe,2 written by Isaac Asimov, the prolific popularizer well known also for his science fiction.
Taken together, then, the Weinberg and Asimov books provide us with a picture of the way science today sees the creation and evolution of the universe.
Since both authors are concerned with explaining how scientists have arrived at their current views, each devotes considerable attention to the observational evidence supporting the theoretical description. Asimov, addressing an audience one infers from his style to be intelligent but naive, limits his methodological discussion to describing the phenomena in question and explaining clearly and succinctly why the theoretical explanations he provides are superior to the alternatives. Weinberg, by contrast, who wishes to explain how physicists actually think about such questions, is considerably more expansive in this regard.
The main point of Weinberg’s book is that current cosmological theory, unlike earlier attempts, is supported by experimental observation as well as by theory. The particular observation crucial to establishing the theory is that an extremely low level of continuous radiation can be detected, bombarding the earth equally from all directions. This radiation is the same radiation which filled the universe during the early stages of creation; it has gradually been stretched out with the expansion of the universe.
The existence of such cosmic radiation is a logical consequence of the “big-bang” theory of creation originated by George Gamow in the 1940′s, and it was in fact predicted by Gamow’s collaborators, Alpher and Herman, in 1948. They were not aware at the time, however, that radio astronomers could build equipment capable of receiving signals as faint as this background would have to be. It was not until 1964 that a group led by R. H. Dicke at Princeton set out to look for this radiation, but before their experiment yielded any results, they were informed that Penzias and Wilson, two radio astronomers at the Bell Telephone Laboratories, had discovered a mysterious background radiation interfering with another experiment they were attempting. Being unaware of the predictions of cosmological theory, Penzias and Wilson had attempted unsuccessfully to account for the radiation by a variety of hypotheses, one even being that it originated in a layer of bird droppings coating their equipment.
The question of whether the universe as we know it has always existed or came into existence at some point in time has been a favorite topic of philosophers and scientists throughout the ages. Plato believed that the universe had been created (but not ex nihilo) whereas Aristotle held it to be eternal. In more recent times, the generally accepted starting point for cosmological arguments has been the cosmological principle, which states that the universe at large should appear the same to observers at all points in space. The theory of the “steady-state” universe, propounded by Hoyle, Bondi, and Gold after World War II in opposition to Gamow’s big-bang theory, was based on the “perfect cosmological principle,” or the belief that the universe should appear the same not only to observers at all points in space but also to observers at all points in time. This principle, as attractive to the philosophical mind now as it was to Aristotle, implied, given the evidence of an expanding universe, that matter had to be created continuously ex nihilo (at an undetectably slow rate) so that the average density of the universe remained constant. The discovery of cosmic radiation, with its implication of a distinctly different earlier state in the condition of the universe, destroyed the tenability of this steady-state theory. Thus the story told by Weinberg demonstrates how another major problem has moved from the realm of philosophy to that of physics.
Weinberg’s book provides the reader with a further insight into the actual workings of science. He is able to espouse the new theory with enthusiasm despite the relative paucity of the actual hard experimental evidence. While the theory behind the detailed calculations is solidly based on experimentally confirmed laws, the observations which provide the actual numbers inserted into the equations are rather limited in number. The whole picture of the early universe is built on three experimental results, in connection with which much uncertainty remains. We see, therefore, that Weinberg’s confidence regarding the theory is based to a large extent on its aesthetic appeal: the theory is not inconsistent with observation, of course, but its real attraction lies in its elegance and intuitive correctness.
While the existence of this tendency to adopt an attractive theory before it has been conclusively proved is significant from an epistemological point of view, it is by no means an argument against the theory, since it is just this subjective “feel” of rightness which leads to the general acceptance of a theory once the formal requirement is met of its not being contradicted by experiment. Thus Copernicus advanced his heliocentric theory to replace the complicated Ptolemaic mechanism of cycles and epicycles, which could describe planetary orbits adequately, even before the invention of the telescope made possible observations of a precision that would have rendered the older method of calculation hopelessly unwieldy.3 Similarly, Einstein’s belief in relativity was based more on his profound faith in the symmetry of nature than on the negative results of precise experiments designed to detect the presence of the ether, a hypothetical medium thought to occupy all space.
Weinberg’s faith, then, lies in the order of nature as expressed in mathematically elegant laws. He states his credo in a brief concluding note: “The more the universe seems comprehensible to us, the more it also seems pointless. But . . . the effort to understand the universe is one of the very few things that lifts human life a little above the level of farce and gives it some of the grace of tragedy.” What this really means is that Weinberg believes that the search for knowledge can be justified in terms of some extra-scientific imperative. He expresses this imperative in literary terms, an emotionally acceptable substitute for the religious terms with which modern Jewish intellectuals are uncomfortable. Nevertheless, in brief references at the beginning and end of the book, Weinberg chooses to quote from an obscure, and extremely anthropomorphic, Norse creation myth, presumably to demonstrate the superior grasp of reality provided by the scientific approach.
This example of a non-scientific approach to cosmology, which features a giant and a cow, is a rather surprising choice. It is hard to believe that someone of Weinberg’s intellectual breadth could have failed to be reminded by the cosmic radiation background, a still extant relic of the literal first day of creation, of the creation account in the book of Genesis. And had he paid more attention to the possibility of valid descriptions of reality arrived at by other than scientific investigation, he might have been led to the midrashic account given by Rabbi Eliezer, an account which was a source of difficulty for Moses Maimonides, schooled in Aristotelian philosophy, but should appear strangely familiar to the reader of Weinberg’s book:
Whence were the heavens created? He took part of the light of His garment, stretched it like a cloth, and thus the heavens were extended continuously, as it is said (Psalms 104, 2): “He covereth Himself with light as with a garment, He stretcheth the heavens like a curtain.”
1 Basic Books, 188 pp., $8.95.
2 Walker, 208 pp., $8.95.
3 It is amusing to speculate that had the computer been invented before Copernicus, Ptolemaic calculations would have been immeasurably simplified, thereby removing one of the most important attractions of the heliocentric theory.