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21 June, 2001 che suryagrahan

(Marathi Vidnyan Parishad Patrika, 2015-04-10) Narlikar, J. V.

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3C 273 : A gravitationally lensed quasar?

(EDP Sciences, 1984-05-30) Chitre, S. M.; Narasimha, D.; Narlikar, J. V.; et al.

It is suggested that the abnormal brightness of the quasar 3C 273, coupled with the observations of superluminal motions in its radio core B as well as the misalignment of its VLBI jet with the optical jet, can be understood by postulating a faint spheroidal lensing galaxy located about halfway along the line of sight to the quasar. The lens model also helps to understand why the quasar is found slightly off-centre with respect to its nebulosity. The probability for such a lens system to arise for 3C 273 by chance is shown to be no less than that computed on the basis of the relativistic beaming hypothesis. Further tests of the lens model are discussed.

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400 years of astronomical discoveries

(Financial chronicle, 2009-11-02) Narlikar, J. V.

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Aakashatale dole

(Saptahik sihasan, 2000-08-02) Narlikar, J. V.

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Aakashvani aani me

(2015-04-10) Narlikar, J. V.

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Abbe' Georges Lamaitree:Father of the Primeval Atom

(Current science, 1994-01-01) Naralikar, J.V.

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Abhyaranya

(Chhatra prabodhan, 2000-02-01) Narlikar, J. V.

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Absorber theory of radiation in expanding universe

(Kluwer Academic Publishers, 2002-10-28) Narlikar, J. V.

The Wheeler-Feynman absorber theory of radiation of the symmetric combination of retarded and advanced potentials, originally developed in a static universe model, is applied to asymptotic boundary conditions for an action-at-a-distance electro dynamic framework of a Quasi-Steady State Universe; which as discussed is in opposition to the broad class of Big bang cosmologies.

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Absorber theory of radiation in expanding universes

(Astronomical Society of India, 1995-04-14) Narlikar, J. V.

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Academy fellowship problem

(Indian Academy of Sciences, 1995-12-25) Narlikar, J. V.

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Action and reaction in the theories of direct interparticle action

(Elsevier Science Publishers, 1975-08-12) Narlikar, J. V.

Newton’s third law of motion is examined in the context of the theories of direct interparticle action. In such theories, interactions between particles travel backward and forward in time at speeds not exceeding the speed of light. It is shown that while in the flat spacetime the equality of action and reaction can be clearly demonstrated, the situation is considerably more complicated in the curved spacetime. The phenomenon of gravitational scattering intervenes to destroy the equality of action and reaction. Nevertheless, when gravitation is taken into account, there is no violation of the con- servation law of energy and momentum. These results are discussed in the framework of general relativity for the case of the electromagnetic interaction.

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Action at a distance and cosmology : A historical perspective

(Annual Reviews Inc., 2003-06-04) Narlikar, J. V.

The first law of theoretical physics, the Newtonian law of gravitation, relies on the concept of action at a distance. The success of this law led to the concept being applied to electricity and magnetism, which were next to be explored in depth. Here the action at a distance had a limited success and ultimately had to be abandoned in favor of the increasingly more popular field theory. Nevertheless, in the 1940s, an attempt was made to revive the concept of action at a distance in a relativistically in-variant way by Wheeler & Feynman (1945, 1949). It inspired a series of investigations in both electrodynamics and gravity in which the field concept was not used but the interaction was described as taking place directly between particles. As it impinged very intimately on cosmology, Hoyle was keenly interested in it. This review discusses the work by Hoyle, the author, and others on the development of electrodynamics and gravitation as direct particle theories. In this review, the author discusses how the work was started and went through stages of increasing sophistication, e.g., extending the Wheeler-Feynman electrodynamics to curved spacetime, its consequences in different cosmologies, and the issues arising from its quantization. The resolution of ultraviolet divergences in quantum electrodynamics is also briefly discussed. The parallel development of a Machian theory of gravitation followed the lead from electrodynamics. In both theories one sees a strong link between the large-scale structure of the universe and local physics, as might be expected from an action-at-a-distance framework.

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Action at a distance electromagnetism

(Science today, 1974-01-01) Narlikar, J. V.

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Action at a distance in electrodynamics and inertia

(Nova Science Publishers, 2001-03-14) Narlikar, J. V.

This paper reviews the parallel development of electrodynamics and gravitation as direct particle theories, echoing the ideals of Ernst Mach. It is shown that a synthesisj of Mach's ideas with these two interactions leads to their better conceptual understanding, Both interactions, however, show that the resulting framework is relativistically invariant and thus precludes instantaneous action at a distance. At the same time, they establish a strong link between the large scale structure of the universe and local phys.cs, as might be expected from an action at a distance framework.