Research Papers (JVN)
Permanent URI for this collectionhttp://localhost:4000/handle/11007/400
Browse
18 results
Search Results
Item Critical reactions to the hot big bang interpretation(Cambridge University Press, 2009-09-14) Burbidge, G.Item Astronomy at the millennium(2002-03-27) Narlikar, J. V.This paper will highlight the important developments in astronomy in the last decade of the twentieth century and in the opening years of the twenty-first, On the observational front, the discovery of extra-solar planets, the detection of gamma- ray bursts and studies of the distances of extragalactic supernovae with implications for the expansion of the universe are the major developments highlighted here. On the theoretical front, the paper reports on the speculations in very high energy physics that have implications for cosmology, the role of the cosmological constant and the quasi-steady state cosmology proposed as an alternative to the big bang.Item Interpretations of the accelerating universe(Astronomical Society of the Pacific, 2002-10-26) Narlikar, J. V.; Vishwakarma, R. G.; Burbidge, G.It is generally argued that the present cosmological observations support the accelerating models of the universe, as driven by the cosmological constant or `dark energy'. We argue here that an alternative model of the universe is possible which explains the current observations of the universe. We demonstrate this with a reinterpretation of the magnitude-redshift relation for Type Ia supernovae, since this was the test that gave a spurt to the current trend in favour of the cosmological constant.Item 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.Item Stochastic creation process and large scale structure in cosmology(International Indian Statistical Association, 2000-03-20) Narlikar, J. V.Item Counting of radio sources: A personal perspective(Kluwer, Dordrecht, 2000-03-25) Narlikar, J. V.This article gives the author's personal perspective on the continuing efforts by radio astronomers to determine the nature of the cosmological model by counting radio sources in the universe out to different levels of faintness. Although initially the source counts were expected to reveal the underlying geometry of space and time, subsequent experience showed that the issue is mixed up with the physical properties of the sources and their evolution with epoch. It is shown, how the earlier claims of disproof of the steady state model through source sounts, turned out to rest on very uncertain evidence.Item Alternative cosmology: The QSSC(International Astronomical Union, 1999-03-24) Narlikar, J. V.This review begins with a brief survey of the observational constraints on the standard big bang cosmology, pointing out that the various limits leave a very narrow window in the parameter space of plausible models. There is thus a strong case for alternative cosmologies. The rest of the review concentrates on one alternative, the quasi steady state cosmology (QSSC) and summaries the recent work on this model. The includes the theoretical formulation and simple exact solution of the basic equations, their relationship to observations, the stability of solutions and the toy model for understanding the growth of structures in the universe.Item Relativistic cosmology(Kluwer, Dordrecht, 1997-09-22) Narlikar, J. V.The subject of cosmology is an admixture of imaginative ideas, intuitive predictions and hard scientific facts. This has made cosmology a case of three distinct cultures; that of astronomers, who look at the universe and find hard data, relativists - who build models of universe that range from simple to esoteric ones, and the particle physicists who can test their the- ories of very high energy physics only in the cosmic laboratory that was there at the very onset of the universe. This culture can well be compared with the British culture, where one has three classes: the working class, the professionals and the aristrocrats. This course will try to give certain glimpses of cosmology in these three fields.Item How universal is Hubble's law?(Indian Mathematical Society, 1995-05-18) Narlikar, J. V.Item Cosmology and action at a distance electrodynamics(American Physical Society, 1995-04-24) Hoyle, F.; Narlikar, J. V.This article reviews the developments in the electrodynamics of direct interparticle action, em-phasizing the achievements in quantum as well as classical electrodynamics. It is shown that the application of the Wheeler-Feynman absorber theory of radiation places stringent requirements on the asymptotic future and past light cones of the universe. All Friedmann cosmologies fail to meet these requirements, but the steady-state and the quasi-steady-state models have the right kind of structure to make the theory work. Further, it is shown that the working theory is free from the problems of divergence that trouble the classical and quantum field theory. In particular, no renormalization is needed: The bare mass and bare charge of an electron are finite. A few ideas relating to the response of the universe to a local microscopic experiment are presented as well as on possible clues to the outstanding issues of foundations of quantum theory