Dark Energy Theory And Observations Pdf

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The visible universe — including Earth, the sun, other stars , and galaxies — is made of protons, neutrons, and electrons bundled together into atoms. Perhaps one of the most surprising discoveries of the 20th century was that this ordinary, or baryonic, matter makes up less than 5 percent of the mass of the universe.

Dandala R. Reddy, Sergei D. Presently we are witnessing a period of rapid and intense change in our understanding of the gravitational force, at a rate that is quickly increasing since the important observational discoveries of the late s.

The Mystery of Dark Energy and Some Revelations

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[Luca Amendola, Shinji Tsujikawa] Dark Energy theory and observations.pdf

Dark energy and some alternatives: a brief overview. The high-quality cosmological data, which became available in the last decade, have thrusted upon us a rather preposterous composition for the universe which poses one of the greatest challenges theoretical physics has ever faced: the so-called dark energy. By focusing our attention on specific examples of dark energy scenarios, we discuss three different candidates for this dark component, namely, a decaying vacuum energy or time-varying cosmological constant [ L t ], a rolling homogeneous quintessence field F , and modifications in gravity due to extra spatial dimensions. As discussed, all these candidates [along with the vacuum energy or cosmological constant L ] seem somewhat to be able to explain the current observational results, which hampers any definitive conclusion on the actual nature of the dark energy. Keywords: Dark energy; Cosmological constant; Extra dimensions. According to Einstein's general theory of relativity, the dynamic properties of a given space-time are fully determined by its total energy content. In the cosmological context, for instance, this amounts to saying that in order to understand the space-time structure of the Universe one needs to identify the relevant sources of energy as well as their contributions to the total energy momentum tensor T m n.

PDF | This work provides the current theory and observations behind the cosmological phenomenon of dark energy. The approach is.

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Here, we consider the modified holographic Ricci dark energy defined by Chen and Jing [21] as the suitable condition of dark energy. We have solved field equations of Brans-Dicke theory of gravitation with the help of an axially symmetric anisotropic Bianchi-type space-time. Here the various phenomena like the expanding universe, and shift from anisotropy to isotropy are observed in this model.

Skip to search form Skip to main content You are currently offline. Some features of the site may not work correctly. Amendola and S. Amendola , S.

Dark Energy: Theory and Observations

Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. What is the universe made of? The answer to this very simple question is not so simple. Baryons, the familiar neutrons and protons of which we, Earth, and the stars are made of, do not account for most of the mass in the universe. Instead, we appear to live in a universe composed primarily of new, unfamiliar, and unidentified forms of matter and energy.

Observational data has lead us to believe that the Universe is undergoing an accelerated expansion. Understanding the nature of dark energy is the focus of many current studies, and its origin being unknown, these studies are largely focused on model building and constraining its parameters. In this article, we discuss how the accelerated expansion of the Universe is driven by dark energy and how dark energy parameters are constrained by observations. This is a preview of subscription content, access via your institution. Rent this article via DeepDyve. Google Scholar.

In physical cosmology and astronomy , dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovae, which showed that the universe does not expand at a constant rate; rather, the expansion of the universe is accelerating. Prior to these observations, the only forms of matter-energy known to exist were ordinary matter , antimatter , dark matter , and radiation. Measurements of the cosmic microwave background suggest the universe began in a hot Big Bang , from which general relativity explains its evolution and the subsequent large-scale motion. Without introducing a new form of energy, there was no way to explain how an accelerating universe could be measured. Since the s, dark energy has been the most accepted premise to account for the accelerated expansion. As of , there are active areas of cosmology research aimed at understanding the fundamental nature of dark energy.

PDF | On Jun 28, , Alicia Bueno Belloso published The Nature of Dark Energy: Theory and Observations | Find, read and cite all the research you need on.

5 Response
  1. Edaldasad

    [Luca Amendola, Shinji Tsujikawa] Dark Energy theory and biblebelieverspentecostal.org Ghazaly Yunus. ContentsPreface page ix List of frequently used symbols xiii 1.

  2. Juliette D.

    The visible universe — including Earth, the sun, other stars , and galaxies — is made of protons, neutrons, and electrons bundled together into atoms.

  3. StГ©phane R.

    It has made a huge impact on cosmology, prompting theoreticians to explain the observations and introducing the concept of dark energy into modern physics. A.

  4. George F.

    Invisible dark matter makes up most of the universe — but we can only detect it from its gravitational effects.

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