Testing the relativistic theories of gravity

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Clifford M. Will describes, in Theory and Experiment in Gravitational Physics, [1] the emergence of a new era for general relativity, testing and checking at very high levels of accuracy. In 1959, scientists at Lincoln Laboratories in Massachusetts bombarded the … Read More

Evaluation of post-Einsteinian gravitational theories through parameterized post-Newtonian formalism

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Proliferation of post-Einsteinian gravitational theories Right after the elaboration and success of general relativity (GR), alternative theories for gravity began to appear, which can fall into four broad categories: [1] Bifurcated theories (with the Lakatosian[2] hard core identical or very … Read More

Tests and Anomalies of Post-Newtonian Gravitational Theories

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Tests of post-Newtonian theories Newton’s proposed tests In the first edition of Principia, Newton considered that the experiments with the pendulum would allow him to decipher the different types of resistance force and their variation with speed. It recognizes the … Read More

Proliferation of Post-Newtonian, Non-Relativistic Theories

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Theoreticians have formulated a set of fundamental criteria that any theory of gravity should satisfy, two purely theoretical and two that are based on experimental evidence[1]. Thus, a theory must be: complete (capable of analyzing from the “first principles” the … Read More

Heuristics of Newtonian Gravity

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The classic example of a successful research program is Newton’s gravitational theory, probably the most successful Lakatosian research program. Initially, Newton’s gravitational theory faced a lot of “anomalies” (“counterexamples”) and contradicted the observational theories that supported these anomalies. But supporters … Read More

Epistemology of Newtonian Gravity

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In certain research programs, such as the mechanistic theory of the universe according to which the universe is a huge clock (and a system of vortices) with the push as the sole cause of movement, the particular Cartesian metaphysics functioned … Read More

Gravity and gravitational tests

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Gravity has a universal character, but its strength rapidly decreases with distance, being the weakest of the four fundamental forces of physics[1]. In the 4th century BC, the Greek philosopher Aristotle considered as the cause of the fall of heavy … Read More

Ontology of Gravitational Singularities

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Peter Bokulich and Erik Curiel (Curiel and Bokulich 2018) assert that general relativity (GR) allows singularities, and that we need to understand the ontology of singularities if we want to understand the nature of space and time in the present … Read More

Gravitational Singularities

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Within the classical theory of Newton’s gravity there is the fundamental possibility of singularity. No signal can propagate from within a singularity, but its gravitational influence is permanently present externally and depends only on the total mass, the angular momentum, … Read More

Newton-Hooke controversy in the opinion of scientists

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A presentation of Hooke’s 1674 monograph introducing the idea of universal gravity was included in the Philosophical Transactions (Royal Society 1775) and subsequently several letters containing observations, including one of Huygens. But obviously, after the publication of Principia in 1687, … Read More

Classical theory of singularities

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Nicolae Sfetcu Email: nicolae@sfetcu.com The singularities from the general relativity resulting by solving Einstein’s equations were and still are the subject of many scientific debates: Are there singularities in spacetime, or not? Big Bang was an initial singularity? If singularities … Read More

Hooke’s claim on the law of gravity

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Since ancient times, Aristotle has represented the universe as transparent concentric spheres, with the Earth in the center, then, outwardly, the spheres of the Moon, the planets, and the fixed stars. But he did not try to give any explanation … Read More

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