{
  "id": "1205.4055",
  "version": "v2",
  "published": "2012-05-17T22:48:47.000Z",
  "updated": "2015-04-10T16:14:52.000Z",
  "title": "Machian gravity and a cosmology without dark matter and dark energy",
  "authors": [
    "Santanu Das"
  ],
  "comment": "12 pages",
  "categories": [
    "gr-qc",
    "astro-ph.CO"
  ],
  "abstract": "The standard model of cosmology is based on the general theory of relativity and demands more than 95\\% of the universe to consist of dark matter and dark energy that has no direct observational evidence till date. The foundation of the concept these dark components are based on a fixed relation between the strength of the gravitational field and the matter density. Alternate models are put forward in past to explain the observations without dark components in the universe. Though they have their own merits and draw backs. In this paper we propose a new cosmological model based on Mach's principle. It provides a similar cosmology as that of the standard cosmological model without any ad-hoc dark matter or dark energy. We show that the theory naturally provides some geometric terms that behave like dark mater and dark energy and dark radiation. The presence of dark radiation provides new observational features in cosmology. We show that the theory is supported by observational data from Big Bang Nucleosynthesis and Cosmic Microwave Background, and provides an explanations for excess number of effective neutrino species and higher Helium mass fraction in the universe. We also calculate the best fit cosmological parameters for our model using Planck+WP data.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2012-05-17T22:48:47.000Z",
      "title": "Cosmological solution of Machian gravity",
      "abstract": "The standard model of cosmology predicts that more than 95% matter in the universe consists of dark components namely dark matter and dark energy. In spite of several attempts to measure these components, there is not a single direct observational evidence for these components till date. Hence, different alternate models of cosmology have been put forward by different authors. However, most of these models have their own problems. Therefore, in this paper, a new cosmological model has been proposed. This model is based on the Machian gravity model, which will be discussed in detail in a later paper. The model can provide an exactly similar cosmology as that of the standard cosmological model without demanding any ad-hoc dark matter or dark energy components. The paper shows that when the field equations from Machian gravity (a 5 dimensional model) are projected to the 4-dimensional space-time, some new mathematical terms arise in the equations that behave exactly like dark matter and dark energy. These mathematical terms come completely from the geometry of the universe and therefore these do not have any connection with the real matter. As the General theory of Relativity does not follow Mach's principle, the FLRW model that is based on GR, cannot provide the correct solution to the cosmological model and demands extra forms of matter and energy to give any predictions consistent with the observations.",
      "comment": "9 pages",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2015-04-10T16:14:52.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cosmological solution",
      "cosmological model",
      "single direct observational evidence",
      "components till date",
      "demands extra forms"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1115268,
      "adsabs": "2012arXiv1205.4055D"
    }
  }
}