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A mathematical proof is given that Maxwell's equations are an {\it artifact} of Hodge theory together with the laws of Gauss and Amp\`ere, taken as axioms. They are thus geometric in nature, independent of any specific physical mechanisms,…

General Physics · Physics 2013-11-05 D. H. Sattinger

All the relativistic cosmological models of the universe, except Einstein's static model, imply that the 3-space of the spacetime of the universe is also expanding apart from the matter and the radiation in it. However, there is no…

General Physics · Physics 2009-01-15 R. K. Thakur

In the present article we find a new class of solutions of Einstein's field equations. It describes stationary, cylindrically symmetric spacetimes with closed timelike geodesics everywhere outside the symmetry axis. These spacetimes contain…

General Relativity and Quantum Cosmology · Physics 2010-04-20 Oyvind Gron , Steinar Johannesen

Questioning the experimental basis of continuous descriptions of fundamental interactions we discuss classical gravity as an effective continuous first-order approximation of a discrete interaction. The sub-dominant contributions produce a…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Manoelito M de Souza

The Einstein theories of space-time and gravity as well the stander cosmology are reconstructed thoroughly in this paper based on flat reference frame. The rational parts of the Einstein theories are reserved while the irrational parts…

General Physics · Physics 2007-05-23 Mei Xiaochun

Our main purpose here is to study some qualitative aspects of space and time. These include the notion of space and time regarded as the containers of respectively bodies and events, the divisibility of space, and the unrepeatability of…

History and Philosophy of Physics · Physics 2012-05-09 Mauricio Mondragon , Luis Lopez

We consider the motion of small bodies in general relativity. The key result captures a sense in which such bodies follow timelike geodesics (or, in the case of charged bodies, Lorentz-force curves). This result clarifies the relationship…

General Relativity and Quantum Cosmology · Physics 2018-11-14 Robert Geroch , James Owen Weatherall

The linearized Einstein theory in the approximately flat time-space is modified accounting for a massive graviton as a dark matter in the universe. On the basis of magnetic-type Maxwell- Proca -Vlasov equations, the interactions of the…

Plasma Physics · Physics 2013-06-05 Xiao-qing Li

We consider a body in a parallel flow of non-interacting particles. One can imagine that the flow is highly rarefied or consists of light rays. The interaction of particles with the body is perfectly elastic. We introduce the notions of a…

Optics · Physics 2009-01-20 Alena Aleksenko , Alexander Plakhov

The matter content of the Universe is generally regarded as a perfect fluid on sufficiently large scales, for all epochs. But the recent cosmological matter distribution, consisting of an (ideally) random distribution of gravitationally…

Astrophysics · Physics 2007-05-23 Brett Bochner

In general relativity, a gravitational horizon (more commonly known as the "apparent horizon") is an imaginary surface beyond which all null geodesics recede from the observer. The Universe has an apparent (gravitational) horizon, but…

General Relativity and Quantum Cosmology · Physics 2018-09-19 Fulvio Melia

The Einstein theories of space-time and gravity as well the stander cosmology are reconstructed thoroughly in this paper based on flat reference frame. The rational parts of the Einstein theories are reserved while the irrational parts…

General Physics · Physics 2007-05-23 Mei Xiaochun

In this article, we examine the possibility that there exist special scalar-tensor theories of gravity with completely nonsingular FRW solutions. Our investigation in fact shows that while most probes living in such a Universe never see the…

High Energy Physics - Theory · Physics 2009-09-15 Nemanja Kaloper , Keith A. Olive

The possibility to describe the laws of the Universe in a computational way seems to be correlated to a principle that the density of information is bounded. This principle, that is dual to that of a finite velocity of information, has…

Logic in Computer Science · Computer Science 2023-04-18 Pablo Arrighi , Gilles Dowek

The continuous charge density of the r^{-4} radial astroelectron is found analytically from the Maxwell-Lorentz equations. The electric charge is not a basic concept, but is the nonlinear field distribution associated with the elementary…

General Physics · Physics 2008-07-08 I. E. Bulyzhenkov

We show that there exist asymptotically flat almost-smooth initial data for Einstein-perfect fluid's equation that represent an isolated liquid-type body. By liquid-type body we mean that the fluid energy density has compact support and…

General Relativity and Quantum Cosmology · Physics 2011-04-21 Sergio Dain , Gabriel Nagy

Light waves carry along their own gravitational field; for simple plain electromagnetic waves the gravitational field takes the form of a pp-wave. I present the corresponding exact solution of the Einstein-Maxwell equations and discuss the…

General Relativity and Quantum Cosmology · Physics 2018-09-19 Jan Willem van Holten

In contemporary physics space and time are intertwined entities so that kinematical and dynamical quantities are expressed in the four-dimensional space-time. This formulation seems to contradict our every-day experience and perception…

General Physics · Physics 2023-05-23 Orfeu Bertolami

After a brief summary of the foundations of general relativity, we will concentrate on the stationary exact solutions of the Einstein and Einstein-Maxwell equations. A number of these solutions can be interpreted as black holes,…

General Relativity and Quantum Cosmology · Physics 2011-09-06 Gérard Clément

The lack of a well-established solution for the gravitational energy problem might be one of the reasons why a clear road to quantum gravity does not exist. In this paper, the gravitational energy is studied in detail with the help of the…

General Relativity and Quantum Cosmology · Physics 2023-08-25 J. B. Formiga , João Duarte