The Genesis of General Relativity: Volume 4 (original) (raw)
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Editorial introduction to the special issue "The Renaissance of Einstein’s Theory of Gravitation".
European Physical Journal H, 2017
Einstein’s 1915 theory of gravitation, also known as General Relativity, is now considered one of the pillars of modern physics. It contributes to our understanding of cosmology and of fundamental interactions between particles. But that was not always the case. Between the mid-1920s and the mid-1950s, General Relativity underwent a period of stagnation, during which the theory was mostly considered as a stepping-stone for a superior theory. In a special issue of EPJ H just published, historians of science and physicists actively working on General Relativity and closely related fields share their views on the process, during the post-World War II era, in particular, which saw the “Renaissance” of General Relativity, following progressive transformation of the theory into a bona fidae physics theory. In this special issue, new insights into the historical process leading to this renaissance point to the extension of the foundation of the original theory, ultimately leading to a global transformation in its character. Contributions from several experts reveals that the theory of 1915 was insufficient to reach firm conclusions without being complemented by intuitions drawn from the resources of pre-relativistic physics. Or, in the case of cosmology, the theory needed to be complemented by philosophical considerations that were hardly generalizable to help solve more mundane problems. As physicist Pascual Jordan puts it, there was a “mismatch between the simplicity of the physical and epistemological foundations and the annoying complexity of the corresponding thicket of formulae.” A number of contributions in this special issue also explain how the theory underwent a period of successive controversies, leading by the 1960s, to the renaissance of the theory. Subsequently, it became in the 1970s, an important, empirically well-tested branch of theoretical physics related to the new, successful sub-discipline of relativistic astrophysics.
2013
cal physics: from Einstein’s 1909 paper back to late nineteenth-century theoretical p hysics”, in Isabella Tassani (a cura di), Oltre la fisica normale. Interpretazioni alternativ e e teorie non standard nella fisica moderna, pp. 25-52. © 2013 Isonomia, Rivista online di Filosofia – Epis temologica – ISSN 2037-4348 Università degli Studi di Urbino Carlo Bo http://isonomia.uniurb.it/epistemologica Widening the boundaries of classical physics: from Einstein’s 1909 paper back to late nineteenth-century theoretical physics
The Renaissance of General Relativity: How and Why it Happened.”
Annalen der Physik, 2016
After an initial burst of excitement about its extraordinary implications for our concept of space and time, the theory of general relativity underwent a thirty-year period of stagnation, during which only a few specialists worked on it, achieving little progress. In the aftermath of World War II, however, general relativity gradually re-entered the mainstream of physics, attracting an increasing number of practitioners and becoming the basis for the current standard theory of gravitation and cosmology-a process Clifford Will baptized the Renaissance of General Relativity. The recent detection of gravitational radiation by the LIGO experiment can be seen as one of the most outstanding achievements in this long-lasting historical process. In the paper, we present a new multifaceted historical perspective on the causes and characteristics of the Renaissance of General Relativity, focusing in particular on the case of gravitational radiation in order to illustrate this complex and far-reaching process.
Science & Education, 2009
The revolution in XX century physics, induced by relativity theories, had its roots within the electromagnetic conception of Nature. It was developed through a tradition related to Brunian and Leibnizian physics, to the German Naturphilosophie and English XIXth physics. The electromagnetic conception of Nature was in some way realized by the relativistic dynamics of Poincaré of 1905. Einstein, on the contrary, after some years, linked relativistic dynamics to a semi-mechanist conception of Nature. He developed general relativity theory on the same ground, but Hilbert formulated it starting from the electromagnetic conception of Nature. Here, a comparison between these two conceptions is proposed in order to understand the conceptual foundations of special relativity within the context of the changing world views. The whole history of physics as well as history of science can be considered as a conflict among different worldviews. Every theory, as well as every different formulation of a theory implies a different worldview: a particular image of Nature implies a particular image of God (atheism too has a particular image of God) as well as of mankind and of their relationship. Thus, it is very relevant for scientific education to point out which image of Nature belongs to a particular formulation of a theory, which image comes to dominate and for which ideological reason.
THE REVENGE OF HISTORY: TWO 19th CENTURY ALTERNATIVES TO SPECIAL RELATIVITY
Here are two rational alternatives to Special Relativity that preserve commonsense. Almost all of the dramatic results arising from the theory of special relativity derive from the kinematic consequences of the Lorentz transformation, especially with respect to its impact on the time dimension, where it appears to result in dynamical effects. An analysis of the Lorentz transformation herein shows that equally valid alternative kinematic assumptions lead to the earlier (1887) Voigt transform, which is usually viewed as simply equivalent to the Lorentz transform in the transverse spatial dimensions. This is shown NOT to be the case, and the Voigt transformations are shown to be much closer to the classical (Galilean) transforms. Einstein's derivation of the Lorentz transform is shown to rely on a critical, third hypothesis, namely one of symmetry between the two inertial reference frames; this assumption is shown not to be reflected in the actual physics of optical observations. It is also emphasized here that Relativity is a derived theory – being based on the validity of classical Maxwell electrodynamics. Although Maxwell's implicit assumption of continuity of electric charge has been shown by von Laue to be incompatible with the relativistic treatment of mass points, relativity has been universally accepted as the theory for treating point electrons. Planck's 1907 proposal for redefining the momentum of a particle is shown to be the critical foundation of relativistic particle dynamics, however, this proposal is independent of the Special Theory of Relativity and is neither derived from this theory nor do its results (including the infamous formula, E = mc 2) validate SRT. (Einstein's 1905 analysis of particle dynamics is incorrect and all of his attempts to derive the equivalence of mass and energy were failures.) However, Planck's proposal is shown to be valid only for electrostatic forces – a result that has major negative implications for all of today's quantum field theories. When the Voigt results are combined with Heaviside's 1888 results for delayed electromagnetic interactions between two moving charged particles, an understandable and consistent interpretation of these famous velocity-sensitive experiments is obtained. This demonstrates that the 'unusual' high-speed effects that are often attributed to relativity result only from " magnetic " effects becoming comparable to the " electric " ones. The combination of these two approaches, from almost forgotten 19th Century physicists, provides a new impetus for reexamining the delayed action-at-a-distance approach to electro-magnetism proposed first by Gauss, the greatest mathematician of this earlier century. This new coherent approach, when combined with a more fundamental 'Relativity Principle', provides a superior research program for consolidating the peculiar (velocity-sensitive) characteristics of the electromagnetic interaction with the velocity independent foundations of classical particle dynamics. This restores the natural philosophy of Isaac Newton, involving absolute space and absolute time, to a unified relativistic framework that should be viewed as a superior alternative to the contradictory and bizarre results of the Lorentz transformation derived from Maxwellian field theory and its 20th Century successors. The "rush to explanation", exemplified by using coordinate transformations to explain the increasing difficulty of accelerating charged particles as they increase their energy and extended unstable particle lifetimes at high velocities, has avoided the search for more realistic dynamical explanations of many high-velocity phenomena. In fact, particle lifetimes are the only physical 'evidence' for accepting the validity of the special theory of relativity as a universal basis for all of modern physics. However, even this result is contradicted by Planck's invariant quantum of action which all field theories (whether subject to Lorentz or Voigt transformations) predict to vary with relative velocity. In summary, the detailed analysis presented herein demonstrates that the special theory of relativity is, at best, an arbitrary theory of mathematical transformations divorced from the microphysical foundations of the electromagnetic phenomena it is supposedly based upon.