The Lens of Gravity

Author(s):  
David D. Nolte

This chapter describes how gravity provided the backdrop for one of the most important paradigm shifts in the history of physics. Prior to Albert Einstein’s general theory of relativity, trajectories were paths described by geometry. After the theory of general relativity, trajectories are paths caused by geometry. This chapter explains how Einstein arrived at his theory of gravity, relying on the space-time geometry of Hermann Minkowski, whose work he had originally harshly criticized. The confirmation of Einstein’s theory was one of the dramatic high points in twentieth-century history of physics when Arthur Eddington journeyed to an island off the coast of Africa to observe stellar deflections during a solar eclipse. If Galileo was the first rock star of physics, then Einstein was the first worldwide rock star of science.

Author(s):  
Hanoch Gutfreund ◽  
Jürgen Renn ◽  
John Stachel

This richly annotated facsimile edition of “The Foundation of General Relativity” introduces a new generation of readers to Albert Einstein's theory of gravitation. Written in 1915, this remarkable document is a watershed in the history of physics and an enduring testament to the elegance and precision of Einstein's thought. Presented here is a beautiful facsimile of Einstein's original handwritten manuscript, along with its English translation and an insightful page-by-page commentary that places the work in historical and scientific context. The concise introduction traces Einstein's intellectual odyssey from the special to the general theory of relativity, and the chapter “The Charm of a Manuscript” provides a delightful meditation on the varied afterlife of Einstein's text. The book also includes a biographical glossary of the figures discussed in the book, a comprehensive bibliography, suggestions for further reading, and numerous photos and illustrations throughout.


Author(s):  
Claus Beisbart

Cosmological questions (e.g., how far the world extends and how it all began) have occupied humans for ages and given rise to numerous conjectures, both within and outside philosophy. To put to rest fruitless speculation, Kant argued that these questions move beyond the limits of human knowledge. This article begins with Kant’s doubts about cosmology and shows that his arguments presuppose unreasonably high standards on knowledge and unwarranted assumptions about space-time. As an analysis of the foundations of twentieth-century cosmology reveals, other worries about the discipline can be avoided too if the universe is modeled using Einstein’s general theory of relativity. There is now strong observational support for one particular model. However, due to underdetermination problems, the big cosmological questions cannot be fully answered using this model either. This opens the space for more speculative proposals again (e.g., that the universe is only part of a huge multiverse).


2021 ◽  
Vol 58 (4) ◽  
pp. 175-195
Author(s):  
Vladimir P. Vizgin ◽  

The article is based on the concepts of epistemic virtues and epistemic vices and explores A. Einstein’s contribution to the creation of fundamental physical theories, namely the special theory of relativity and general theory of relativity, as well as to the development of a unified field theory on the basis of the geometric field program, which never led to success. Among the main epistemic virtues that led Einstein to success in the construction of the special theory of relativity are the following: a unique physical intuition based on the method of thought experiment and the need for an experimental justification of space-time concepts; striving for simplicity and elegance of theory; scientific courage, rebelliousness, signifying the readiness to engage in confrontation with scientific conventional dogmas and authorities. In the creation of general theory of relativity, another intellectual virtue was added to these virtues: the belief in the heuristic power of the mathematical aspect of physics. At the same time, he had to overcome his initial underestimation of the H. Minkowski’s four-dimensional concept of space and time, which has manifested in a distinctive flexibility of thinking typical for Einstein in his early years. The creative role of Einstein’s mistakes on the way to general relativity was emphasized. These mistakes were mostly related to the difficulties of harmonizing the mathematical and physical aspects of theory, less so to epistemic vices. The ambivalence of the concept of epistemic virtues, which can be transformed into epistemic vices, is noted. This transformation happened in the second half of Einstein’s life, when he for more than thirty years unsuccessfully tried to build a unified geometric field theory and to find an alternative to quantum mechanics with their probabilistic and Copenhagen interpretation In this case, we can talk about the following epistemic vices: the revaluation of mathematical aspect and underestimation of experimentally – empirical aspect of the theory; adopting the concepts general relativity is based on (continualism, classical causality, geometric nature of fundamental interactions) as fundamental; unprecedented persistence in defending the GFP (geometrical field program), despite its failures, and a certain loss of the flexibility of thinking. A cosmological history that is associated both with the application of GTR (general theory of relativity) to the structure of the Universe, and with the missed possibility of discovering the theory of the expanding Universe is intermediate in relation to Einstein’s epistemic virtues and vices. This opportunity was realized by A.A. Friedmann, who defeated Einstein in the dispute about if the Universe was stationary or nonstationary. In this dispute some of Einstein’s vices were revealed, which Friedman did not have. The connection between epistemic virtues and the methodological principles of physics and also with the “fallibilist” concept of scientific knowledge development has been noted.


It is shown how to obtain, within the general theory of relativity, equations of motion for two oscillating masses at the ends of a spring of given law of force. The method of Einstein, Infeld & Hoffmann is used, and the force in the spring is represented by a stress singularity. The detailed calculations are taken to the Newtonian order.


2021 ◽  
Author(s):  
Manfred Geilhaupt

Abstract Derivation of mass (m), charge (e) and fine structure constant (FSC) from theory are unsolved problems in physics up to now. Neither the Standard Model (SM) nor the General theory of Relativity (GR) has provided a complete explanation for mass, charge and FSC. The question “of what is rest mass” is therefore still essentially unanswered. We will show that the combination of two Principle Theories, General Relativity and Thermodynamics (TD), is able to derive the restmass of an electron (m) which surprisingly depends on the (Sommerfeld) FSC (same for the charge (e)).


2019 ◽  
pp. 265-284
Author(s):  
Steven J. Osterlind

This chapter provides the context for the early twentieth-century events contributing to quantification. It was the golden age of scientific exploration, with explorers like David Livingstone, Sir Richard Burton, and Sir Ernest Shackleton, and intellectual pursuits, such as Hilbert’s set of unsolved problems in mathematics. However, most of the chapter is devoted to discussing the last major influencer of quantification: Albert Einstein. His life and accomplishments, including his theory of relativity, make up the final milestone on our road to quantification. The chapter describes his time in Bern, especially in 1905, when he published several famous papers, most particularly his law of special relativity, and later, in 1915, when he expanded it to his theory of general relativity. The chapter also provides a layperson’s description of the space–time continuum. Women of major scientific accomplishments are mentioned, including Madame Currie and the mathematician Maryam Mirzakhani.


Author(s):  
Geoff Cottrell

By the beginning of the twentieth century, our understanding of matter was completely transformed by the great discoveries of electromagnetism and relativity. ‘Energy, mass, and light’ outlines Einstein’s special theory of relativity of 1905, which describes what happens when objects move at speeds close to the speed of light. The theory transformed our understanding of the nature of space and time, and matter through the equivalence of mass and energy. In 1916, Einstein extended the theory to include gravity in the general theory of relativity, which revealed that matter affects space by curving space around it.


2020 ◽  
Vol 35 (08) ◽  
pp. 2050045
Author(s):  
Nisha Godani ◽  
Gauranga C. Samanta

Morris and Thorne1 proposed traversable wormholes, hypothetical connecting tools, using the concept of Einstein’s general theory of relativity. In this paper, the modification of general relativity (in particular [Formula: see text] theory of gravity defined by Harko et al.2) is considered, to study the traversable wormhole solutions. The function [Formula: see text] is considered as [Formula: see text], where [Formula: see text] and [Formula: see text] are controlling parameters. The shape and redshift functions appearing in the metric of wormhole structure have significant contribution in the development of wormhole solutions. We have considered both variable and constant redshift functions with a logarithmic shape function. The energy conditions are examined, geometric configuration is analyzed and the radius of the throat is determined in order to have wormhole solutions in absence of exotic matter.


Science ◽  
2019 ◽  
Vol 365 (6454) ◽  
pp. 664-668 ◽  
Author(s):  
Tuan Do ◽  
Aurelien Hees ◽  
Andrea Ghez ◽  
Gregory D. Martinez ◽  
Devin S. Chu ◽  
...  

The general theory of relativity predicts that a star passing close to a supermassive black hole should exhibit a relativistic redshift. In this study, we used observations of the Galactic Center star S0-2 to test this prediction. We combined existing spectroscopic and astrometric measurements from 1995–2017, which cover S0-2’s 16-year orbit, with measurements from March to September 2018, which cover three events during S0-2’s closest approach to the black hole. We detected a combination of special relativistic and gravitational redshift, quantified using the redshift parameter ϒ. Our result, ϒ = 0.88 ± 0.17, is consistent with general relativity (ϒ = 1) and excludes a Newtonian model (ϒ = 0) with a statistical significance of 5σ.


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