Principles of Physical Cosmology

2020 ◽  
Author(s):  
P. J. E. Peebles
Keyword(s):  
General Relativity ◽  
Large Scale ◽  
Large Scale Structure ◽  
Critical Area ◽  
Nobel Lecture ◽  
Modern Physics ◽  
History Of ◽  
Cosmological Tests ◽  
Physical Cosmology ◽  
The Universe

This book is the essential introduction to this critical area of modern physics, written by a leading pioneer who has shaped the course of the field for decades. The book provides an authoritative overview of the field, showing how observation has combined with theory to establish the science of physical cosmology. The book presents the elements of physical cosmology, including the history of the discovery of the expanding universe; surveys the cosmological tests that measure the geometry of space-time, with a discussion of general relativity as the basis for these tests; and reviews the origin of galaxies and the large-scale structure of the universe. Now featuring the author's 2019 Nobel lecture, the book remains an indispensable reference for students and researchers alike.

Homogeneity and Clustering

2020 ◽  
pp. 3-36
Author(s):  
P. J. E. Peebles
Keyword(s):  
General Relativity ◽  
Large Scale ◽  
Albert Einstein ◽  
Large Scale Structure ◽  
Relativity Theory ◽  
Expanding Universe ◽  
History Of ◽  
Edwin Hubble ◽  
The Universe ◽  
Georges Lemaître

This chapter traces the history of the development of ideas on the large-scale structure of the universe. Modern discussions of the nature of the large-scale matter distribution can be traced back to three central ideas. In 1917, Albert Einstein argued that a closed homogeneous world model fits very well into general relativity theory and the requirements of Mach's principle. In 1926, Edwin Hubble showed that the large-scale distribution of galaxies is close to uniform with no indication of an edge or boundary. In 1927, Georges Lemaître showed that the uniform distribution of galaxies fits very well with the pattern of galaxy redshifts. The chapter then assesses several questions. The first is whether the universe really is homogeneous. Could the homogeneity of the universe have been deduced ahead of time from general principles? Or might it be a useful guide to new principles? It also asks how clustering evolves in an expanding universe, what its origin is, and what this reveals about the nature of the universe.

Philosophy of Cosmology

Philosophy ◽  
2019 ◽  
Author(s):  
Craig Fox ◽  
Marie Gueguen ◽  
Adam Koberinski ◽  
Chris Smeenk
Keyword(s):  
Large Scale ◽  
Central Area ◽  
Fundamental Physics ◽  
Philosophy Of Cosmology ◽  
History Of ◽  
Physical Cosmology ◽  
The Universe ◽  
Scientific Debates ◽  
Scientific Fields ◽  
General Philosophy Of Science

Physical cosmology, the study of the large-scale structure of the universe and its evolution, has become a central area of research in fundamental physics. Theoretical and observational developments have led to acceptance of a “standard model” describing the history of the universe in impressive detail. These developments raise a number of challenging foundational questions that have stimulated the emerging field of philosophy of cosmology. Many of these questions are closely tied to discussions in general philosophy of science and philosophy of physics, whereas others are distinctive to the field. This bibliography aims to provide an orientation for both kinds of questions. As philosophy of cosmology is an emerging field, the literature in this area is sparse. Hence this bibliography includes two kinds of references that do not explicitly address philosophy of cosmology. First, it identifies several philosophical papers regarding other scientific fields, with the thought that these will inform discussions of parallel issues in cosmology. Second, it includes several references to the scientific literature, to provide philosophers with a useful orientation to contemporary scientific debates.

scholarly journals Cosmological Tests of Gravity

2019 ◽  
Vol 57 (1) ◽  
pp. 335-374 ◽  
Author(s):  
Pedro G. Ferreira
Keyword(s):  
General Relativity ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Alternative Theories Of Gravity ◽  
Systematic Uncertainties ◽  
Cosmological Observations ◽  
Theories Of Gravity ◽  
Tests Of Gravity ◽  
The Universe

Cosmological observations are beginning to reach a level of precision that allows us to test some of the most fundamental assumptions in our working model of the Universe. One such assumption is that gravity is governed by the theory of general relativity. In this review, we discuss how one might go about extending general relativity and how such extensions can be described in a unified way on large scales. This allows us to describe the phenomenology of modified gravity in the growth and morphology of the large-scale structure of the Universe. On smaller scales, we explore the physics of gravitational screening and how it might manifest itself in galaxies, clusters, and, more generally, in the cosmic web. We then analyze the current constraints from large-scale structure and conclude by discussing the future prospects of the field in light of the plethora of surveys currently being planned. Key results include the following: ▪ There are a plethora of alternative theories of gravity that are restricted by fundamental physics considerations. ▪ There is now a well-established formalism for describing cosmological perturbations in the linear regime for general theories of gravity. ▪ Gravitational screening can mask modifications to general relativity on small scales but may, itself, lead to distinctive signatures in the large-scale structure of the Universe. ▪ Current constraints on both linear and nonlinear scales may be affected by systematic uncertainties that limit our ability to rule out alternatives to general relativity. ▪ The next generation of cosmological surveys will dramatically improve constraints on general relativity, by up to two orders of magnitude.

scholarly journals A new golden age: testing general relativity with cosmology

2011 ◽  
Vol 369 (1957) ◽  
pp. 4941-4946
Author(s):  
Rachel Bean ◽  
Pedro G. Ferreira ◽  
Andy Taylor
Keyword(s):  
General Relativity ◽  
Large Scale ◽  
Large Scale Structure ◽  
Einstein Gravity ◽  
Field Equations ◽  
The Past ◽  
Cosmological Observations ◽  
Wide Range ◽  
Theories Of Gravity ◽  
The Universe

Gravity drives the evolution of the Universe and is at the heart of its complexity. Einstein's field equations can be used to work out the detailed dynamics of space and time and to calculate the emergence of large-scale structure in the distribution of galaxies and radiation. Over the past few years, it has become clear that cosmological observations can be used not only to constrain different world models within the context of Einstein gravity but also to constrain the theory of gravity itself. In this article, we look at different aspects of this new field in which cosmology is used to test theories of gravity with a wide range of observations.

scholarly journals Using the morphology and magnetic fields of tailed radio galaxies as environmental probes

2014 ◽  
Vol 10 (S313) ◽  
pp. 321-326
Author(s):  
M. Johnston-Hollitt ◽  
S. Dehghan ◽  
L. Pratley
Keyword(s):  
Magnetic Fields ◽  
Large Scale ◽  
Large Population ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Local Conditions ◽  
History Of ◽  
Unique Source ◽  
The Universe ◽  
The Magnetic Field

AbstractBent-tailed (BT) radio sources have long been known to trace over densities in the Universe up to z ~ 1 and there is increasing evidence this association persists out to redshifts of 2. The morphology of the jets in BT galaxies is primarily a function of the environment that they have resided in and so BTs provide invaluable clues as to their local conditions. Thus, not only can samples of BT galaxies be used as signposts of large-scale structure, but are also valuable for obtaining a statistical measurement of properties of the intra-cluster medium including the presence of cluster accretion shocks & winds, and as historical anemometers, preserving the dynamical history of their surroundings in their jets. We discuss the use of BTs to unveil large-scale structure and provide an example in which a BT was used to unlock the dynamical history of its host cluster. In addition to their use as density and dynamical indicators, BTs are useful probes of the magnetic field on their environment on scales which are inaccessible to other methods. Here we discuss a novel way in which a particular sub-class of BTs, the so-called ‘corkscrew’ galaxies might further elucidate the coherence lengths of the magnetic fields in their vicinity. Given that BTs are estimated to make up a large population in next generation surveys we posit that the use of jets in this way could provide a unique source of environmental information for clusters and groups up to z = 2.

scholarly journals Testing general relativity: from local to cosmological scales

2011 ◽  
Vol 369 (1957) ◽  
pp. 5042-5057 ◽  
Author(s):  
Jean-Philippe Uzan
Keyword(s):  
General Relativity ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Geometric Structures ◽  
Tests Of General Relativity ◽  
The Universe

I summarize various tests of general relativity on astrophysical scales, based on the large-scale structure of the universe but also on other systems, in particular the constants of physics. I emphasize the importance of hypotheses on the geometric structures of our universe while performing such tests and discuss their complementarity as well as their possible extensions.

scholarly journals Stephen William Hawking CH CBE. 8 January 1942—14 March 2018

2019 ◽  
Vol 66 ◽  
pp. 267-308
Author(s):  
Bernard J. Carr ◽  
George F. R. Ellis ◽  
Gary W. Gibbons ◽  
James B. Hartle ◽  
Thomas Hertog ◽  
...  
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Quantum Mechanics ◽  
Large Scale ◽  
Early Years ◽  
Singularity Theorems ◽  
Post Graduate Student ◽  
History Of ◽  
The 1960S ◽  
The Universe

Stephen Hawking's contributions to the understanding of gravity, black holes and cosmology were truly immense. They began with the singularity theorems in the 1960s followed by his discovery that black holes have an entropy and consequently a finite temperature. Black holes were predicted to emit thermal radiation, what is now called Hawking radiation. He pioneered the study of primordial black holes and their potential role in cosmology. His organization of and contributions to the Nuffield Workshop in 1982 consolidated the picture that the large-scale structure of the universe originated as quantum fluctuations during the inflationary era. Work on the interplay between quantum mechanics and general relativity resulted in his formulation of the concept of the wavefunction of the universe. The tension between quantum mechanics and general relativity led to his struggles with the information paradox concerning deep connections between these fundamental areas of physics. These achievements were all accomplished following the diagnosis during the early years of Stephen's studies as a post-graduate student in Cambridge that he had incurable motor neuron disease—he was given two years to live. Against all the odds, he lived a further 55 years. The distinction of his work led to many honours and he became a major public figure, promoting with passion the needs of disabled people. His popular best-selling book, A brief history of time , made cosmology and his own work known to the general public world-wide. He became an icon for science and an inspiration to all.

scholarly journals Magnetic Fields in Galaxy Clusters and in the Large-Scale Structure of the Universe

Galaxies ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 142 ◽  
Author(s):  
Valentina Vacca ◽  
Matteo Murgia ◽  
Federica Govoni ◽  
Torsten Enßlin ◽  
Niels Oppermann ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Galaxy Clusters ◽  
Large Scale ◽  
Large Scale Structure ◽  
Scale Structure ◽  
Quality Data ◽  
High Quality Data ◽  
History Of ◽  
The Universe ◽  
Detailed Picture

The formation and history of cosmic magnetism is still widely unknown. Significant progress can be made through the study of magnetic fields properties in the large-scale structure of the Universe: galaxy clusters, filaments, and voids of the cosmic web. A powerful tool to study magnetization of these environments is represented by radio observations of diffuse synchrotron sources and background or embedded radio galaxies. To draw a detailed picture of cosmic magnetism, high-quality data of these sources need to be used in conjunction with sophisticated tools of analysis.

Inflationary models of the primordial universe

2018 ◽  
Author(s):  
Nathalie Deruelle ◽  
Jean-Philippe Uzan
Keyword(s):  
Large Scale ◽  
Initial Conditions ◽  
Large Scale Structure ◽  
Big Bang ◽  
Scale Structure ◽  
Fine Tuning ◽  
Accelerated Expansion ◽  
History Of ◽  
Big Bang Model ◽  
The Universe

This chapter addresses the problem of fine-tuning the initial conditions of the previous chapter’s hot Big Bang model, so that the universe has the observed properties, as well as the problem of the origin of large-scale structure. It shows that these problems are related to each other, and can be solved by assuming a period of accelerated expansion in the earliest history of the universe. Since the 1980s, the general acceptance of this idea of a primordial inflationary phase can be considered as the third phase in the history of the development of relativistic cosmology. The chapter first outlines the issues with the hot Big Bang model: the flatness problem; the Big Bang horizon, and monopole problems; and the problem of the origin of the large-scale structure. It then provides a solution in the form of inflation, and goes on to discuss ‘chaotic’ inflation.

scholarly journals Model-independent tests of cosmic gravity

2011 ◽  
Vol 369 (1957) ◽  
pp. 4985-4997 ◽  
Author(s):  
Eric V. Linder
Keyword(s):  
General Relativity ◽  
Phase Space ◽  
Large Scale ◽  
Classification Scheme ◽  
Large Scale Structure ◽  
Gravity Models ◽  
Model Independent ◽  
Space Dynamics ◽  
Absolute Criterion ◽  
The Universe

Gravitation governs the expansion and fate of the universe, and the growth of large-scale structure within it, but has not been tested in detail on these cosmic scales. The observed acceleration of the expansion may provide signs of gravitational laws beyond general relativity (GR). Since the form of any such extension is not clear, from either theory or data, we adopt a model-independent approach to parametrizing deviations to the Einstein framework. We explore the phase space dynamics of two key post-GR functions and derive a classification scheme, and an absolute criterion on accuracy necessary for distinguishing classes of gravity models. Future surveys will be able to constrain the post-GR functions' amplitudes and forms to the required precision, and hence reveal new aspects of gravitation.

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