Do We Really Understand the Cosmos?

Abstract

Our knowledge about the universe has increased tremendously in the last three decades or so --- thanks to the progress in observations --- but our understanding has improved very little. There are several fundamental questions about our universe for which we have no answers within the current, operationally very successful, approach to cosmology. Worse still, we do not even know how to address some of these issues within the conventional approach to cosmology. This fact suggests that we are missing some important theoretical ingredients in the overall description of the cosmos. I will argue that these issues --- some of which are not fully appreciated or emphasized in the literature --- demand a paradigm shift: We should not think of the universe as described by a specific solution to the gravitational field equations; instead, it should be treated as a special physical system governed by a different mathematical description, rooted in the quantum description of spacetime. I will outline how this can possibly be done.

Invited Review; 28 pages; 1 figure

References in corpus (6)

• The Atoms Of Space, Gravity and the Cosmological Constant
• Vacuum Fluctuations and the Small Scale Structure of Spacetime
• Cosmological Constant from the Emergent Gravity Perspective
• Particle creation, classicality and related issues in quantum field theory: I. Formalism and toy models
• The origin of dark matter, matter-anti-matter asymmetry, and inflation
• Quantum Evolution Leading to Classicality: A Concrete Example

Cited by in corpus (18)

• Does information entropy play a role in the expansion and acceleration of the Universe?
• Cosmic Information, the Cosmological Constant and the Amplitude of primordial perturbations
• Gravity and Quantum Theory: Domains of Conflict and Contact
• Accelerated Expansion of the Universe based on Emergence of Space and Thermodynamics of the Horizon
• Quantum Correlators in Friedmann Spacetimes -The omnipresent de Sitter and the invariant vacuum noise
• The atoms of spacetime and the cosmological constant
• Configuration entropy of the Cosmic Web: Can voids mimic the dark energy?
• Thermodynamics in the universe described by the emergence of the space and the energy balance relation
• First Law of Thermodynamics and Emergence of Cosmic Space in a Non-Flat Universe
• Configuration entropy in the $\Lambda$CDM and the dynamical dark energy models: Can we distinguish one from the other?
• Varying fundamental constants: a full covariant approach and cosmological applications
• Horizon thermodynamics and cosmological equations: A holographic-like connection between thermostatistical quantities on a cosmological horizon and in the bulk
• A study of holographic dark energy models using configuration entropy
• Cosmological model based on both holographic-like connection and Padmanabhan's holographic equipartition law
• Can we constrain the dark energy equation of state parameters using configuration entropy?
• Holographic thermodynamic relation for dissipative and non-dissipative universes in a flat FLRW cosmology
• On cosmological expansion and local physics
• Cosmological scenario based on the first and second laws of thermodynamics: Thermodynamic constraints on a generalized cosmological model