Origins and Bibliography of the Big Bang Theory ORIGINS: Background & Bibliography ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Assembled for the PHILOsophy Conference of: Computer Connection PO Box 382 BBS (609) 784-9404 Voorhees, NJ 08043 by T.A. Hare Nov. 13, 1985 Topic: Areas of interaction between philosophy, science, andreligion. Part I – Big Bang (Astronomy) Part II – Unified Field (Particle Physics) Part III – Evolution (Biology). Part IV – Theologic interaction – – – – Part II – Unified Field Theory of Particle Physics: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ And God said, “Let there be an expanse between the waters to separate water from water.” (Gen.
1:6) And God said, “Let the water under the sky be gathered to one place, and let dry ground appear.” And it was so. (Gen. 1:9) – – – – Further reading: 1. John H. Schwartz, “Completing Einstein”, SCIENCE 85, vol 6, pp 60-64, 1985. 2.
Robert Palmer, “What’s a Quark?”, SCIENCE 85, VOL 6, pp 66-71, 1985 3. Bruce Schechter, “The Moment of Creation”, DISCOVER, April 1983, pp 18-25. 4. Lawrence R. Sulak, “Waiting for the Proton to Decay”, AMERICAN SCIENTIST, 70, 616-625, 1982. 5. Mary K.
Gaillard, “Toward a Unified Picture of Elementary Particle Interactions”, AMERICAN SCIENTIST 70, 506-514. – – – – The following background articles were downloaded from American Adacemic Encyclopedia via Dow Jones News Retrevial Service; Nov 12, 1985 UNIFIED FIELD THEORY Classical attempts at devising a unified field theory, principally those of Einstein, were concerned with the combination of gravitation (the general theory of RELATIVITY) and electromagnetism into the same theoretical framework. Electromagnetism is described by MAXWELL’S EQUATIONS for an antisymmetric tensor, whereas Einstein’s theory of gravitation centers about a symmetric metric tensor; Einstein’s idea was to combine both descriptions into a single, nonsymmetric tensor, thereby treating both subjects from an essentially geometric point of view. Other attempts to incorporate electromagnetism into the basically geometric formalism of general relativity were made by Hermann Weyl (1918) and more recently by John Wheeler; although some theories are more esthetic than others, all lack the connection with quantum phenomena that is so important for interactions other than gravitation. More-recent attempts at unification have been made from the quite different point of view of merging the quantum field theories that (are supposed to) describe the four FUNDAMENTAL INTERACTIONS of gravity, electromagnetism, and the weak and the strong nuclear interactions.
The most palatable unification so far has been given by Steven WEINBERG of Harvard University and independently by Abdus SALAM of Imperial College, London, joining electromagnetism and the weak interactions. In the simplest version of this type of unified gauge theory, forces are transmitted by the exchange of four different types of particles called bosons, which are assumed to be massless. By means of a “broken symmetry” an effective generation of masses occurs, so that the Weinberg-Salam theory envisages the weak interactions as being transmitted by massive “W” mesons, in which one meson, identified with the photon, remains massless, while the other three, identified with the quanta that transmit the weak interaction, are estimated to be quite heavy. Their rest-mass energies are on the order of 50 to 100 times the mass of the proton, and their observation should become possible with the next generation of high-energy accelerators. So far, the Weinberg-Salam theory has passed every unambiguous test to which it has been subjected. Weinberg and Salam shared the 1979 Nobel Prize for physics for their model. Many other unified theories, involving strong interaction and even gravitation, have recently been proposed. Such grand unification schemes to date have unavoidable and questionable consequences, such as the removal of the separate conservation of baryon and lepton number; they predict a proton could decay into a lepton plus pions–an improbable event that is actively being searched for at present.
Recent grand unification schemes require the existence of magnetic MONOPOLES. These hypothetical particles, also called grand unification monopoles (GUMs), are thought to be very massive, with a mass ranging from 10 to the 16th power to 10 to the 19th power GeV. No experimental evidence of monopoles has yet been found. H. M.
FRIED Bibliography Bergmann, Peter G., Introduction to the Theory of Relativity (1942; repr. 1976) Einstein, Albert, The Meaning of Relativity, 5th ed. (1956) Hadlock, Charles, Field Theory and Its Classical Problems (1979) Tonnelat, Marie A., Einstein’s Theory of Unified Fields (1966). – – – – RELATIVITY Albert Einstein’s theory of relativity has caused major revolutions in physics and astronomy during the 20th century. It introduced to science the concept of “relativity”–the notion that there is no absolute motion in the universe, only relative motion–thus superseding the 200-year-old theory of mechanics of Isaac Newton.
Einstein showed that we reside not in the flat, Euclidean space and uniform, absolute time of everyday experience, but in another environment: curved space-time. The theory played a role in advances in physics that led to the nuclear era, with its potential for benefit as well as for destruction, and that made possible an understanding of the microworld of elementary particles and their interactions. It has also revolutionized our view of COSMOLOGY, with its predictions of apparently bizarre astronomical phenomena such as the BIG BANG, NEUTRON STARS, BLACK HOLES, and gravitational waves (see GRAVITATION). Scope of Relativity The theory of relativity is a single, all-encompassing theory of space-time, gravitation, and mechanics. It is popularly viewed, however, as having two separate, independent theoretical parts– special relativity and general relativity.
One reason for this division is that Einstein presented special relativity in 1905, while general relativity was not published in its final form until 1916. Another reason is the very different realms of applicability of the two parts of the theory: special relativity in the world of microscopic physics, general relativity in the world of astrophysics and cosmology. A third reason is that physicists accepted and understood special relativity by the early 1920s. It quickly became a working tool for theorists and experimentalists in the then-burgeoning fields of atomic and nuclear physics and quantum mechanics. This rapid acceptance was not, however, the case for general relativity. The theory did not appear to have as much direct connection with experiment as the special theory; most of its applications were on astronomical scales, and it was apparently limited to adding miniscule corrections to the predictions of Newtonian gravitation theory; its cosmological impact would not be felt for another decade.
In addition, the mathematics of the theory were thought to be extraordinarily difficult to comprehend. The British astronomer Sir Arthur Eddington, one of the first to fully understand the theory in detail, was once asked if it were true that only three people in the world understood general relativity. He is said to have replied, “Who is the third?” This situation persisted for almost 40 years. General relativity was considered a respectable subject not for physicists, but for pure mathematicians and philosophers. Around 1960, however, a remarkable resurgence of interest in general relativity began that has made it an important and serious branch of physics and astronomy.
(By 1977, Eddington’s remark was recalled at a conference on general relativity attended by more than 800 researchers in the subject.) This growth has its roots, first, beginning around 1960, in the application of new mathematical techniques to the study of general relativity that significantly streamlined calculations and that allowed the physically significant concepts to be isolated from the mathematical complexity, and second, in the discovery of exotic astronomical phenomena in which general relativity could play an important role, including quasars (1963), the 3-kelvin microwave background radiation (1965), pulsars (1967), and the possible discovery of black holes (1971). In addition, the rapid technological advances of the 1960s and ’70s gave experimenters new high-precision tools to test whether general relativity was the correct theory of gravitation. The distinction between special relativity and the curved space-time of general relativity is largely a matter of degree. Special relativity is actually an approximation to curved space-time that is valid in sufficiently small regions of space-time, much as the overall surface of an apple is curved even though a small region of the surface is approximately flat. Special relativity thus may be used whenever the scale of the phenomena being studied is small compared to the scale on which space-time curvature (gravitation) begins to be noticed. For most applications in atomic or nuclear physics, this approximation is so accurate that relativity can be assumed to be exact; in other words, gravity is assumed to be completely absent.
From this point of view, special relativity and all its consequences may be “derived” from a single simple postulate. In the presence of gravity, however, the approximate nature of special relativity may manifest itself, so the principle of equivalence is invoked to determine how matter responds to curved space-time. Finally, to learn the extent that space-time is curved by the presence of matter, general relativity is applied. Special Relativity The two basic concepts of special relativity are the inertial frame and the principle of relativity. An inertial frame of reference is any region, such as a freely falling laboratory (see FREE FALL), in which all objects move in straight lines with uniform velocity.
This region is free from gravitation and is called a Galilean system. The principle of relativity postulates that the result of any physical experiment performed inside a laboratory in an inertial frame is independent of the uniform velocity of the frame. In other words, the laws of physics must have the same form in every inertial frame. A corollary is that the speed of light must be the same in any inertial frame (because a speed-of-light measurement is a physical experiment) regardless of the speed of its source or that of the observer. Essentially all the laws and consequences of special relativity can be derived from these concepts. The first important consequence is the relativity of simultaneity.
Because any operational definition of simultaneous events at different locations involves the sending of light signals between them, then two events that are simultaneous in one inertial frame may not be simultaneous when viewed from a frame moving relative to the first. This conclusion helped abolish the Newtonian concept of an absolute, universal time. In some ways the most important consequences and confirmations of special relativity arise when it is merged with quantum mechanics, leading to many predictions in agreement with experiments, such as elementary particle spin, atomic fine structure, antimatter, and so on. The mathematical foundations of special relativity were explored in 1908 by the German mathematician Hermann Minkowski, who developed the concept of a “four-dimensional space-time continuum,” in which time is treated the same as the three spatial dimensions–the fourth dimension of Minkowski space-time. The Principle of Equivalence and Space-time Curvature The exact Minkowski space-time of special relativity is incompatible with the existence of gravity.
A frame chosen to be inertial for a particle far from the Earth where the gravitational field is negligible will not be inertial for a particle near the Earth. An approximate compatibility between the two, however, can be achieved through a remarkable property of gravitation called the weak equivalence principle (WEP): all modest-sized bodies fall in a given external gravitational field with the same acceleration regardless of their mass, composition, or structure. The principle’s validity has been checked experimentally by Galileo, Newton, and Friedrich Bessel, and in the early 20th century by Baron Roland von Eotvos (after whom such experiments are named). If an observer were to ride in an elevator falling freely in a gravitational field, then all bodies inside the elevator, because they are falling at the same rate, would consequently move uniformly in straight lines as if gravity had vanished. Conversely, in an accelerated elevator in free space, bodies would fall with the same acceleration (because of their inertia), just as if there were a gravitational field.
Einstein’s great insight was to postulate that this “vanishing” of gravity in free-fall applied not only to mechanical motion but …