Research Publications

Permanent URI for this communityhttp://localhost:4000/handle/11007/1

Browse

Start date: 1990Subject: search.filters.subject.Cosmology

Search Results

Now showing 1 - 10 of 58
  • No Thumbnail Available
    Item
    Gelya sahasrakatil vishwasankalpanecha vikas
    (2015-04-10) Narlikar, J. V.
  • No Thumbnail Available
    Item
    Gelya sahasrakatil vishwasankalpanancha vikas
    (2015-04-10) Narlikar, J. V.
  • No Thumbnail Available
    Item
    What is India’s role in the study of the cosmos ?
    (The Times of India, 2015-04-10) Narlikar, J. V.
  • No Thumbnail Available
    Item
    Holy grail of cosmology
    (DNa, 2009-04-01) Naralikar, J.V.
  • No Thumbnail Available
    Item
    Science and speculation: Behind the veil of cosmology
    (The Times of India, 2003-02-01) Naralikar, J.V.
  • No Thumbnail Available
    Item
    Different approach to cosmology
    (Physics today, 1999-10-01) Naralikar, J.V.
  • No Thumbnail Available
    Item
    Cosmology and local environment
    (Indian institute of advanced study, 1990-01-02) Naralikar, J.V.
  • No Thumbnail Available
    Item
    Crisis in cosmology: Observational constraints on Omega and H
    (Overseas Publishers Association, 1996-03-18) Bagla, J. S.; Padmanabhan, T.; Narlikar, J. V.
    This review of recent observations of cosmological interest seeks to take stock of how they constrain the standard hot big bang models with or without inflation. We look at two specific series indicative of this class of models. In one series the flatness condition of inflation requires that the density parameter shall be unity. Of late this statement has been relaxed somewhat to include the cosmological constant also as a contributor to the density parameter. Hence we ha»e used this "generalised" flatness condition. The other series of models does not need (be cosmological constant but assumes that the curvature parameter k = -1. Both these models are currently being pushed as "the" models of the universe. The observational constraints used by us are the measurements of the Hubble constant and the deceleration parameter, the ages of globular clusters, the abundance of primordial deuterium, the abundance of rich clusters, the baryon content of galaxy clusters and the abundance of high rsdshift objects. These constraints essentially limit the allowed values of the cosmological parameters. Our findings are that with measurements within their quoted error bars, the available parameter space has shrunk to negligible proportions. For survival of the standard models, therefore, one needs to take recourse to two normally unpalatable steps: (i) to doubt the existing error bars and hope to expand them and (ii) to fine-tone the theoretical parameters so that they fall within the available space. This is the essence of our perception of the crisis in cosmology.
  • No Thumbnail Available
    Item
    Mach’s principle
    (2011-04-10) Narlikar, J. V.
    The underlying idea in Mach's principle is that the origin of inertia or mass of a particle is a dynamical quantity determined by the environment, in particular the rest of the matter in the universe. In this article, we discuss the role of this idea in the Brans {Dicke theory of gravitation and the Hoyle {Narlikar cosmology.
  • No Thumbnail Available
    Item
    Cosmology and the origin of nuclei
    (2010-04-06) Narlikar, J. V.
    The problem of explaining the origin of all the chemical elements found in the universe is a central problem in astrophysics. In the 1940s Fred Hoyle suggested that they were cooked inside stars, starting with nucleosynthesis of neutrons and protons. In the same decade George Gamow argued that in a hot big bang universe in the first few minutes, the ambient conditions were suitable for formation of nuclei. This paper will review the progress of both these ideas and show that a reasonable compromise between these ideas can be found today.