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

Heuristics of the General Relativity

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The essential principle of coordination in GR is the principle of equivalence, including a negative heuristic. The argument “is not that all reference frames are equivalent, but that the classical coordination of uniform motion in a straight line with the … Read More

Epistemology of General Relativity

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Early philosophical interpretations of the general theory of relativity are very diverse, each trying to identify Einstein as a follower of that philosophy. Mach’s supporters highlighted Einstein’s attempt to implement a “relativization of inertia” in general relativity (GR), and his … 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

The Ontology of General Relativity

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In classical vision, space and time are containers; matter is the content. The distinctive property of matter is that it carries energy and impulse, preserved over time, resulting in energy and impulse being fundamental ontologically. (Norton 2012) General Relativity (GR) … Read More

Grandfather paradox in time travel

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(Top: original billiard ball trajectory. Middle: the billiard ball emerges from the future, and delivers its past self a strike that averts the past ball from entering the time machine. Bottom: the billiard ball never enters the time machine, giving … Read More

Time Travel

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Time travel involves traveling in a time different from the present, in the past or in the future, basically without a space travel with reference to a local coordinate system. Time travel can be made by a material body that … Read More

Special theory of relativity

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Special Theory of Relativity (or Special relativity) is the formal theory elaborated by Albert Einstein in 1905 in order to draw all the physical consequences of Galilean relativity and the principle according to which the speed of light in a … Read More

Einstein’s Relativity

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(Art drawing about the theory of relativity) The theory of relativity includes both the theory of special relativity as that of general relativity formulated by Albert Einstein in the early twentieth century, who sought to resolve the incompatibility between Newtonian mechanics and electromagnetism. The theory of special relativity, published in 1905, deals with the physics of … Read More