Charles D. Bailyn
- Published in print:
- 2014
- Published Online:
- October 2017
- ISBN:
- 9780691148823
- eISBN:
- 9781400850563
- Item type:
- book
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691148823.001.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
Emitting no radiation or any other kind of information, black holes mark the edge of the universe—both physically and in our scientific understanding. Yet astronomers have found clear evidence for ...
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Emitting no radiation or any other kind of information, black holes mark the edge of the universe—both physically and in our scientific understanding. Yet astronomers have found clear evidence for the existence of black holes, employing the same tools and techniques used to explore other celestial objects. This book goes behind the theory and physics of black holes to describe how astronomers are observing these enigmatic objects and developing a remarkably detailed picture of what they look like and how they interact with their surroundings. Accessible to undergraduates and others with some knowledge of introductory college-level physics, this book presents the techniques used to identify and measure the mass and spin of celestial black holes. These key measurements demonstrate the existence of two kinds of black holes, those with masses a few times that of a typical star, and those with masses comparable to whole galaxies—supermassive black holes. The book provides a detailed account of the nature, formation, and growth of both kinds of black holes. The book also describes the possibility of observing theoretically predicted phenomena such as gravitational waves, wormholes, and Hawking radiation. A cutting-edge introduction to a subject that was once on the border between physics and science fiction, this book shows how black holes are becoming routine objects of empirical scientific study.Less
Emitting no radiation or any other kind of information, black holes mark the edge of the universe—both physically and in our scientific understanding. Yet astronomers have found clear evidence for the existence of black holes, employing the same tools and techniques used to explore other celestial objects. This book goes behind the theory and physics of black holes to describe how astronomers are observing these enigmatic objects and developing a remarkably detailed picture of what they look like and how they interact with their surroundings. Accessible to undergraduates and others with some knowledge of introductory college-level physics, this book presents the techniques used to identify and measure the mass and spin of celestial black holes. These key measurements demonstrate the existence of two kinds of black holes, those with masses a few times that of a typical star, and those with masses comparable to whole galaxies—supermassive black holes. The book provides a detailed account of the nature, formation, and growth of both kinds of black holes. The book also describes the possibility of observing theoretically predicted phenomena such as gravitational waves, wormholes, and Hawking radiation. A cutting-edge introduction to a subject that was once on the border between physics and science fiction, this book shows how black holes are becoming routine objects of empirical scientific study.
Joshua S. Bloom
- Published in print:
- 2011
- Published Online:
- October 2017
- ISBN:
- 9780691145570
- eISBN:
- 9781400837007
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691145570.003.0006
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter focuses on how gamma-ray bursts (GRBs) are emerging as unique tools in the study of broad areas of astronomy and physics by virtue of their special properties. The unassailable fact ...
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This chapter focuses on how gamma-ray bursts (GRBs) are emerging as unique tools in the study of broad areas of astronomy and physics by virtue of their special properties. The unassailable fact about GRBs that makes them such great probes is that they are fantastically bright and so can be seen to the farthest reaches of the observable Universe. In parallel with the ongoing study of GRB events and progenitors, new lines of inquiry have burgeoned: using GRBs as unique probes of the Universe in ways that are almost completely divorced from the nature of GRBs themselves. Topics discussed include studies of gas, dust, and galaxies; the history of star formation; measuring reionization and the first objects in the universe; neutrinos, gravitational waves, and cosmic rays; quantum gravity and the expansion of the universe; and the future of GRBs.Less
This chapter focuses on how gamma-ray bursts (GRBs) are emerging as unique tools in the study of broad areas of astronomy and physics by virtue of their special properties. The unassailable fact about GRBs that makes them such great probes is that they are fantastically bright and so can be seen to the farthest reaches of the observable Universe. In parallel with the ongoing study of GRB events and progenitors, new lines of inquiry have burgeoned: using GRBs as unique probes of the Universe in ways that are almost completely divorced from the nature of GRBs themselves. Topics discussed include studies of gas, dust, and galaxies; the history of star formation; measuring reionization and the first objects in the universe; neutrinos, gravitational waves, and cosmic rays; quantum gravity and the expansion of the universe; and the future of GRBs.
I.S. GLASS
- Published in print:
- 2008
- Published Online:
- January 2010
- ISBN:
- 9780199550258
- eISBN:
- 9780191718700
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199550258.003.0008
- Subject:
- Physics, History of Physics
This chapter begins by providing a brief description of Harlow Shapley's biography and early life. It then discusses Harlow's life as a student of the University of Missouri and Princeton. It ...
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This chapter begins by providing a brief description of Harlow Shapley's biography and early life. It then discusses Harlow's life as a student of the University of Missouri and Princeton. It narrates his study with Henry Norris Russell about the discovery of approximate mathematical methods for analysing the behaviour of binary stars. It tells of Shapley's efforts to make himself known in other places. It mentions Shapley's other important works such as his guess that RR Lyrae variables might also be standard candles, the distances of the globular clusters, the discovery of the centre of the Milky Way, and finding the Sculptor and Fornax dwarf galaxies. It also tells of the criticisms and oppositions that he encountered.Less
This chapter begins by providing a brief description of Harlow Shapley's biography and early life. It then discusses Harlow's life as a student of the University of Missouri and Princeton. It narrates his study with Henry Norris Russell about the discovery of approximate mathematical methods for analysing the behaviour of binary stars. It tells of Shapley's efforts to make himself known in other places. It mentions Shapley's other important works such as his guess that RR Lyrae variables might also be standard candles, the distances of the globular clusters, the discovery of the centre of the Milky Way, and finding the Sculptor and Fornax dwarf galaxies. It also tells of the criticisms and oppositions that he encountered.
Abraham Loeb and Steven R. Furlanetto
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691144917
- eISBN:
- 9781400845606
- Item type:
- book
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691144917.001.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our ...
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This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies. The book starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more.Less
This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies. The book starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more.
Abraham Loeb and Steven R. Furlanetto
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691144917
- eISBN:
- 9781400845606
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691144917.003.0008
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter examines galaxies in some detail from a largely theoretical perspective. Along the way, one must bear in mind that, although the described progression of events in this chapter is ...
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This chapter examines galaxies in some detail from a largely theoretical perspective. Along the way, one must bear in mind that, although the described progression of events in this chapter is plausible, at this time it is only a conjecture in the minds of theorists that has not yet been confirmed by observational data. This chapter therefore focuses only on the physics that drive these interstellar objects, showing how the earliest dwarf galaxies eventually merged and made bigger galaxies. A present-day galaxy like our own Milky Way was constructed over cosmic history by the assembly of a million building blocks in the form of the first dwarf galaxies.Less
This chapter examines galaxies in some detail from a largely theoretical perspective. Along the way, one must bear in mind that, although the described progression of events in this chapter is plausible, at this time it is only a conjecture in the minds of theorists that has not yet been confirmed by observational data. This chapter therefore focuses only on the physics that drive these interstellar objects, showing how the earliest dwarf galaxies eventually merged and made bigger galaxies. A present-day galaxy like our own Milky Way was constructed over cosmic history by the assembly of a million building blocks in the form of the first dwarf galaxies.
Adolfo Plasencia
- Published in print:
- 2017
- Published Online:
- January 2018
- ISBN:
- 9780262036016
- eISBN:
- 9780262339308
- Item type:
- book
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262036016.001.0001
- Subject:
- Society and Culture, Technology and Society
The place of discovery and generation of human knowledge has become a somewhat fuzzy area, and it is at the crossroads of equally blurred disciplines where new glimpses of the future occur. This book ...
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The place of discovery and generation of human knowledge has become a somewhat fuzzy area, and it is at the crossroads of equally blurred disciplines where new glimpses of the future occur. This book looks at these issues through a series of interconnected and heterodox reflections. It is much more a book of non-linear questions than one of answers, where the index consists of a list of questions with those who address the issues linked to them. In 33 dialogues, the author attempts to draw the participants, researchers and creators—each specialists—out of their “intellectual comfort zones”, and get them to delve into areas of disciplines not considered part of their usual activities, thus enabling different concepts to be discussed. For example, “intelligence”, viewed simultaneously from the perspective of neuroscience, computer science, philosophy, and Artificial Intelligence, or whether quantum physics allows for freewill. The diversity and interconnecting ideas in these conversations is wide ranging and intense. The dialogues, preceded by a foreword from Tim O’Reilly, are arranged in four blocks: I, The Physical World; II, Information, and III, Intelligence; the fourth block is a dialogue-epilogue with the artist and painter J. M. Yturralde, closing the book with a critical foray into the overlap between Art and Science, with tantalizing questions, with an artistic slant, such as the validity of the equation “Beauty ≠ Truth,” or whether we can go back in time to the past and change it.Less
The place of discovery and generation of human knowledge has become a somewhat fuzzy area, and it is at the crossroads of equally blurred disciplines where new glimpses of the future occur. This book looks at these issues through a series of interconnected and heterodox reflections. It is much more a book of non-linear questions than one of answers, where the index consists of a list of questions with those who address the issues linked to them. In 33 dialogues, the author attempts to draw the participants, researchers and creators—each specialists—out of their “intellectual comfort zones”, and get them to delve into areas of disciplines not considered part of their usual activities, thus enabling different concepts to be discussed. For example, “intelligence”, viewed simultaneously from the perspective of neuroscience, computer science, philosophy, and Artificial Intelligence, or whether quantum physics allows for freewill. The diversity and interconnecting ideas in these conversations is wide ranging and intense. The dialogues, preceded by a foreword from Tim O’Reilly, are arranged in four blocks: I, The Physical World; II, Information, and III, Intelligence; the fourth block is a dialogue-epilogue with the artist and painter J. M. Yturralde, closing the book with a critical foray into the overlap between Art and Science, with tantalizing questions, with an artistic slant, such as the validity of the equation “Beauty ≠ Truth,” or whether we can go back in time to the past and change it.
John Bolender
- Published in print:
- 2010
- Published Online:
- August 2013
- ISBN:
- 9780262014441
- eISBN:
- 9780262289238
- Item type:
- book
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262014441.001.0001
- Subject:
- Neuroscience, Research and Theory
This book proposes a new explanation for the forms of social relations. It argues that the core of social-relational cognition exhibits beauty—in the physicist’s sense of the word, associated with ...
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This book proposes a new explanation for the forms of social relations. It argues that the core of social-relational cognition exhibits beauty—in the physicist’s sense of the word, associated with symmetry. The book describes a fundamental set of patterns in interpersonal cognition that account for the resulting structures of social life in terms of their symmetries and the breaking of those symmetries. It further describes the symmetries of the four fundamental social relations as ordered in a nested series akin to what one finds in the formation of a snowflake or spiral galaxy. Symmetry breaking organizes the neural activity generating the cognitive models which structure our social relationships. The book’s primary claim is that there exists a social pattern generator analogous to the central pattern generators associated with locomotion in many animal species. Spontaneous symmetry breaking structures the activity of the social pattern generator just as it does in central pattern generators. The book’s hypothesis that relational cognition results from self-organization is entirely novel, distinct from other theories, which describe sociality in terms of evolution or environment. It presents a picture of social-relational cognition as resembling something inorganic. In doing so, the hypothesis reveals deep connections among cognition, biology, and the inorganic world. One can go too far, the book acknowledges, in taking a solely dynamical view of the mind; the mind’s innate functional complexity must be due to natural selection. But this does not mean that every simple mental feature is the result of natural selection.Less
This book proposes a new explanation for the forms of social relations. It argues that the core of social-relational cognition exhibits beauty—in the physicist’s sense of the word, associated with symmetry. The book describes a fundamental set of patterns in interpersonal cognition that account for the resulting structures of social life in terms of their symmetries and the breaking of those symmetries. It further describes the symmetries of the four fundamental social relations as ordered in a nested series akin to what one finds in the formation of a snowflake or spiral galaxy. Symmetry breaking organizes the neural activity generating the cognitive models which structure our social relationships. The book’s primary claim is that there exists a social pattern generator analogous to the central pattern generators associated with locomotion in many animal species. Spontaneous symmetry breaking structures the activity of the social pattern generator just as it does in central pattern generators. The book’s hypothesis that relational cognition results from self-organization is entirely novel, distinct from other theories, which describe sociality in terms of evolution or environment. It presents a picture of social-relational cognition as resembling something inorganic. In doing so, the hypothesis reveals deep connections among cognition, biology, and the inorganic world. One can go too far, the book acknowledges, in taking a solely dynamical view of the mind; the mind’s innate functional complexity must be due to natural selection. But this does not mean that every simple mental feature is the result of natural selection.
Michael Goldstein
- Published in print:
- 2011
- Published Online:
- January 2012
- ISBN:
- 9780199694587
- eISBN:
- 9780191731921
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199694587.003.0007
- Subject:
- Mathematics, Probability / Statistics
Computer simulators offer a powerful approach for studying complex physical systems. We consider their use in current practice and the role of external uncertainty in bridging the gap between the ...
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Computer simulators offer a powerful approach for studying complex physical systems. We consider their use in current practice and the role of external uncertainty in bridging the gap between the properties of the model and of the system. The interpretation of this uncertainty analysis raises questions about the role and meaning of the Bayesian approach. We summarize some theory which is helpful to clarify and amplify the role of external specifications of uncertainty, and illustrate some of the types of calculation suggested by this approach.Less
Computer simulators offer a powerful approach for studying complex physical systems. We consider their use in current practice and the role of external uncertainty in bridging the gap between the properties of the model and of the system. The interpretation of this uncertainty analysis raises questions about the role and meaning of the Bayesian approach. We summarize some theory which is helpful to clarify and amplify the role of external specifications of uncertainty, and illustrate some of the types of calculation suggested by this approach.
Gian Francesco Giudice
- Published in print:
- 2009
- Published Online:
- February 2010
- ISBN:
- 9780199581917
- eISBN:
- 9780191723001
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199581917.003.0012
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
Results from the LHC can expand our knowledge of the early stages of the universe. The connection between the world of particle physics and the structure of our universe is probably one of the most ...
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Results from the LHC can expand our knowledge of the early stages of the universe. The connection between the world of particle physics and the structure of our universe is probably one of the most profound results of modern science, which captivates the imagination of anyone who is confronted with its wonders. This chapter describes this connection, explaining how the process of inflation could be at the origin of the cosmological properties we observe today. The empirical evidence in favour of dark matter is by now overwhelming. This still unknown form of matter could be made of some new kind of particle that can be produced at the LHC. This chapter presents the case of dark matter at the LHC and the ways in which the new form of matter could be discovered. It explains what dark energy is and its potential impact on the naturalness problem.Less
Results from the LHC can expand our knowledge of the early stages of the universe. The connection between the world of particle physics and the structure of our universe is probably one of the most profound results of modern science, which captivates the imagination of anyone who is confronted with its wonders. This chapter describes this connection, explaining how the process of inflation could be at the origin of the cosmological properties we observe today. The empirical evidence in favour of dark matter is by now overwhelming. This still unknown form of matter could be made of some new kind of particle that can be produced at the LHC. This chapter presents the case of dark matter at the LHC and the ways in which the new form of matter could be discovered. It explains what dark energy is and its potential impact on the naturalness problem.
della Porta and Caiani Wagemann
- Published in print:
- 2012
- Published Online:
- May 2012
- ISBN:
- 9780199641260
- eISBN:
- 9780191738654
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199641260.003.0003
- Subject:
- Political Science, Comparative Politics
Chapter 3 introduces to the political, social and cultural opportunities for the extreme right in Germany, Italy and the United States, pointing at the mix of similarities and differences between the ...
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Chapter 3 introduces to the political, social and cultural opportunities for the extreme right in Germany, Italy and the United States, pointing at the mix of similarities and differences between the three countries. As the authors explain, Germany and Italy were chosen within a ‘most similar’ logic, where the cases under examination share similarities in most of their characteristics, but some differences in our set of dependent variables (the frames, networks and actions of the extremist right), which are then explained by some contextual differences. The addition of the rather different case of the US extreme right aimed at testing the generalizability of some descriptive and causal inferences that emerged in the previous comparison.Less
Chapter 3 introduces to the political, social and cultural opportunities for the extreme right in Germany, Italy and the United States, pointing at the mix of similarities and differences between the three countries. As the authors explain, Germany and Italy were chosen within a ‘most similar’ logic, where the cases under examination share similarities in most of their characteristics, but some differences in our set of dependent variables (the frames, networks and actions of the extremist right), which are then explained by some contextual differences. The addition of the rather different case of the US extreme right aimed at testing the generalizability of some descriptive and causal inferences that emerged in the previous comparison.
Mike Ashley
- Published in print:
- 2001
- Published Online:
- May 2014
- ISBN:
- 9780853238553
- eISBN:
- 9781781380826
- Item type:
- chapter
- Publisher:
- Liverpool University Press
- DOI:
- 10.5949/liverpool/9780853238553.003.0006
- Subject:
- Literature, Criticism/Theory
This chapter reflects on the fate of the science fiction magazines during the 1950s nuclear age, by which time most science fiction magazines in pulp science fiction formats had disappeared. It notes ...
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This chapter reflects on the fate of the science fiction magazines during the 1950s nuclear age, by which time most science fiction magazines in pulp science fiction formats had disappeared. It notes that with the appearance of new titles such as Galaxy and Magazine of Fantasy in 1950, science fiction had matured to such a point that it expanded to wider audiences. The chapter then discusses the evolution of science fiction magazines from its gadget science fiction phase up to the nuclear science fiction phase.Less
This chapter reflects on the fate of the science fiction magazines during the 1950s nuclear age, by which time most science fiction magazines in pulp science fiction formats had disappeared. It notes that with the appearance of new titles such as Galaxy and Magazine of Fantasy in 1950, science fiction had matured to such a point that it expanded to wider audiences. The chapter then discusses the evolution of science fiction magazines from its gadget science fiction phase up to the nuclear science fiction phase.
Abraham Loeb and Steven R. Furlanetto
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691144917
- eISBN:
- 9781400845606
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691144917.003.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter describes the essential aspects of the modern cosmological paradigm for understanding the formation of the first galaxies in the Universe. The basic question that cosmology attempts to ...
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This chapter describes the essential aspects of the modern cosmological paradigm for understanding the formation of the first galaxies in the Universe. The basic question that cosmology attempts to answer is: What is the composition of the Universe and what initial conditions generated the observed structures in it? The first galaxies were shaped, more than any other class of astrophysical objects, by the pristine initial conditions and basic constituents of the Universe. This chapter shows how studying the formation process of the first galaxies could reveal unique evidence for new physics that has so far remained veiled in older galaxies by complex astrophysical processes.Less
This chapter describes the essential aspects of the modern cosmological paradigm for understanding the formation of the first galaxies in the Universe. The basic question that cosmology attempts to answer is: What is the composition of the Universe and what initial conditions generated the observed structures in it? The first galaxies were shaped, more than any other class of astrophysical objects, by the pristine initial conditions and basic constituents of the Universe. This chapter shows how studying the formation process of the first galaxies could reveal unique evidence for new physics that has so far remained veiled in older galaxies by complex astrophysical processes.
Abraham Loeb and Steven R. Furlanetto
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691144917
- eISBN:
- 9781400845606
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691144917.003.0004
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter examines the intergalactic medium (IGM). Although much of astronomy focuses on the luminous material inside galaxies, the majority of matter today—and the vast majority at z > 6—actually ...
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This chapter examines the intergalactic medium (IGM). Although much of astronomy focuses on the luminous material inside galaxies, the majority of matter today—and the vast majority at z > 6—actually lies outside these structures, in the IGM. This material ultimately provides the fuel for galaxy and cluster formation and—because it is much less affected by the complex physics of galaxies—offers a cleaner view of the underlying physical processes of structure formation and of fundamental cosmology. The chapter thus takes up the study on the properties of the IGM, especially during the era of the first galaxies (when the IGM underwent major changes).Less
This chapter examines the intergalactic medium (IGM). Although much of astronomy focuses on the luminous material inside galaxies, the majority of matter today—and the vast majority at z > 6—actually lies outside these structures, in the IGM. This material ultimately provides the fuel for galaxy and cluster formation and—because it is much less affected by the complex physics of galaxies—offers a cleaner view of the underlying physical processes of structure formation and of fundamental cosmology. The chapter thus takes up the study on the properties of the IGM, especially during the era of the first galaxies (when the IGM underwent major changes).
Abraham Loeb and Steven R. Furlanetto
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691144917
- eISBN:
- 9781400845606
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691144917.003.0011
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter investigates a number of specific observational probes of the high-redshift Universe. It examines the Lyman-α line, an extraordinarily rich and useful—albeit complex—probe of both ...
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This chapter investigates a number of specific observational probes of the high-redshift Universe. It examines the Lyman-α line, an extraordinarily rich and useful—albeit complex—probe of both galaxies and the intergalactic medium (IGM). As established in the previous chapter, young star-forming galaxies can produce very bright Lyman-α emissions. Although the radiative transfer of these photons through their host galaxies is typically very complex, a good starting point is a simple model in which a fraction of stellar ionizing photons are absorbed within their source galaxy, forming embedded H II regions. The resulting protons and electrons then recombine, producing Lyman-α photons. Assuming ionization equilibrium, the rate of these recombinations must equal the rate at which ionizing photons are produced.Less
This chapter investigates a number of specific observational probes of the high-redshift Universe. It examines the Lyman-α line, an extraordinarily rich and useful—albeit complex—probe of both galaxies and the intergalactic medium (IGM). As established in the previous chapter, young star-forming galaxies can produce very bright Lyman-α emissions. Although the radiative transfer of these photons through their host galaxies is typically very complex, a good starting point is a simple model in which a fraction of stellar ionizing photons are absorbed within their source galaxy, forming embedded H II regions. The resulting protons and electrons then recombine, producing Lyman-α photons. Assuming ionization equilibrium, the rate of these recombinations must equal the rate at which ionizing photons are produced.
Abraham Loeb and Steven R. Furlanetto
- Published in print:
- 2013
- Published Online:
- October 2017
- ISBN:
- 9780691144917
- eISBN:
- 9781400845606
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691144917.003.0013
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter discusses several other ways to probe structures during the cosmic dawn. It first turns to secondary anisotropies of the cosmic microwave background, which are generated as the photons ...
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This chapter discusses several other ways to probe structures during the cosmic dawn. It first turns to secondary anisotropies of the cosmic microwave background, which are generated as the photons passed through gas during the cosmic dawn. Next, the chapter turns to diffuse backgrounds from the cosmic dawn, which typically include galactic emission lines, ranging from CO lines in the radio to the Lyman-α line itself. Finally, the chapter observes that fossil structure from early galaxies remains in (or can be deduced from) the Milky Way or other nearby entities in the Local Group. This fossil structure includes the residual effects of feedback on the small satellite galaxies or globular clusters of the Milky Way, old low-mass stars that may have formed during the cosmic dawn and survive inside the Milky Way (or its halo), and remnant signatures of the early merger history of the Milky Way.Less
This chapter discusses several other ways to probe structures during the cosmic dawn. It first turns to secondary anisotropies of the cosmic microwave background, which are generated as the photons passed through gas during the cosmic dawn. Next, the chapter turns to diffuse backgrounds from the cosmic dawn, which typically include galactic emission lines, ranging from CO lines in the radio to the Lyman-α line itself. Finally, the chapter observes that fossil structure from early galaxies remains in (or can be deduced from) the Milky Way or other nearby entities in the Local Group. This fossil structure includes the residual effects of feedback on the small satellite galaxies or globular clusters of the Milky Way, old low-mass stars that may have formed during the cosmic dawn and survive inside the Milky Way (or its halo), and remnant signatures of the early merger history of the Milky Way.
Karel Schrijver and Iris Schrijver
- Published in print:
- 2015
- Published Online:
- April 2015
- ISBN:
- 9780198727439
- eISBN:
- 9780191793615
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198727439.001.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This book tells the fascinating story of what truly makes the human body. The body that is with us all our lives is always changing. We are quite literally not who we were years, weeks, or even days ...
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This book tells the fascinating story of what truly makes the human body. The body that is with us all our lives is always changing. We are quite literally not who we were years, weeks, or even days ago: our cells die and are replaced by new ones at an astonishing pace. The entire body continually rebuilds itself, time and again, using the food and water that flow through us as fuel and as construction material. What persists over time is not fixed but merely a pattern in flux. We rebuild using elements captured from our surroundings, and are thereby connected to animals and plants around us, to the bacteria within us that help digest them, and to geological processes such as continental drift and volcanism here on the Earth. We are also intimately linked to the Sun’s nuclear furnace and to the solar wind, to collisions with asteroids, and to the cycles of the birth of stars and their deaths in cataclysmic supernovae. Ultimately, we are connected to the beginning of the universe. Our bodies are made of stardust, the burned out embers of stars that were released into the galaxy in massive explosions billions of years ago, mixed with atoms that formed only recently as ultrafast cosmic rays slammed into the Earth’s atmosphere. All of that is not just remote history but part of us now: our human body is inseparable from nature all around us, and is intertwined with the history of the universe.Less
This book tells the fascinating story of what truly makes the human body. The body that is with us all our lives is always changing. We are quite literally not who we were years, weeks, or even days ago: our cells die and are replaced by new ones at an astonishing pace. The entire body continually rebuilds itself, time and again, using the food and water that flow through us as fuel and as construction material. What persists over time is not fixed but merely a pattern in flux. We rebuild using elements captured from our surroundings, and are thereby connected to animals and plants around us, to the bacteria within us that help digest them, and to geological processes such as continental drift and volcanism here on the Earth. We are also intimately linked to the Sun’s nuclear furnace and to the solar wind, to collisions with asteroids, and to the cycles of the birth of stars and their deaths in cataclysmic supernovae. Ultimately, we are connected to the beginning of the universe. Our bodies are made of stardust, the burned out embers of stars that were released into the galaxy in massive explosions billions of years ago, mixed with atoms that formed only recently as ultrafast cosmic rays slammed into the Earth’s atmosphere. All of that is not just remote history but part of us now: our human body is inseparable from nature all around us, and is intertwined with the history of the universe.
Nicholas Mee
- Published in print:
- 2020
- Published Online:
- September 2020
- ISBN:
- 9780198851950
- eISBN:
- 9780191886690
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198851950.003.0027
- Subject:
- Physics, History of Physics
There is no way to transcribe the features of the Earth’s spherical surface onto a flat map without some distortion. All maps distort the geography of the sphere. The familiar Mercator maps inflate ...
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There is no way to transcribe the features of the Earth’s spherical surface onto a flat map without some distortion. All maps distort the geography of the sphere. The familiar Mercator maps inflate regions close to the poles compared to regions in the tropics. In 1973, Arno Peters promoted the Gall–Peters projection that compensates for the expansion of polar regions compared to the tropics. Buckminster Fuller invented a map called the Dymaxion in which the globe is projected onto an icosahedron, which is then unfolded into an icosahedral net. Another interesting projection is the Pierce Quincuncial projection invented by Charles Sanders Pierce. The Milky Way galaxy was recently mapped using data from NASA’s Wide-field Infra-red Survey Explorer (WISE) and shown to be a barred spiral galaxy. Pablo Carlos Budassi has created a map of the entire visible universe using NASA images by representing radial distances on a logarithmic scale.Less
There is no way to transcribe the features of the Earth’s spherical surface onto a flat map without some distortion. All maps distort the geography of the sphere. The familiar Mercator maps inflate regions close to the poles compared to regions in the tropics. In 1973, Arno Peters promoted the Gall–Peters projection that compensates for the expansion of polar regions compared to the tropics. Buckminster Fuller invented a map called the Dymaxion in which the globe is projected onto an icosahedron, which is then unfolded into an icosahedral net. Another interesting projection is the Pierce Quincuncial projection invented by Charles Sanders Pierce. The Milky Way galaxy was recently mapped using data from NASA’s Wide-field Infra-red Survey Explorer (WISE) and shown to be a barred spiral galaxy. Pablo Carlos Budassi has created a map of the entire visible universe using NASA images by representing radial distances on a logarithmic scale.
Daniel R. Altschuler and Fernando J. Ballesteros
- Published in print:
- 2019
- Published Online:
- July 2019
- ISBN:
- 9780198844419
- eISBN:
- 9780191879951
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198844419.003.0013
- Subject:
- Physics, History of Physics, Particle Physics / Astrophysics / Cosmology
This chapter is about the Irish scientific writer Agnes Clerke and her work for the popularization of science and astronomy.
This chapter is about the Irish scientific writer Agnes Clerke and her work for the popularization of science and astronomy.
Malcolm Longair
- Published in print:
- 2003
- Published Online:
- May 2013
- ISBN:
- 9780226284132
- eISBN:
- 9780226284163
- Item type:
- chapter
- Publisher:
- University of Chicago Press
- DOI:
- 10.7208/chicago/9780226284163.003.0009
- Subject:
- History, History of Science, Technology, and Medicine
The quasar story goes back to May 1933, when radio astronomy was born. Surveys of the radio sky had revealed a population of extragalactic radio sources, and a few of them were associated with nearby ...
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The quasar story goes back to May 1933, when radio astronomy was born. Surveys of the radio sky had revealed a population of extragalactic radio sources, and a few of them were associated with nearby galaxies that were abnormal in some way. Various discoveries stimulated significant investment in the construction of radio telescopes, leading to the discovery of many more radio sources outside the galaxy. By determining accurate positions for the radio sources, their optical counterparts could be identified. The nature of the quasars remained a mystery. The similarity between quasars and the nuclei of Seyfert galaxies was reinforced by the discovery in 1968 that the continuum emission of the latter is variable, like that of quasars.Less
The quasar story goes back to May 1933, when radio astronomy was born. Surveys of the radio sky had revealed a population of extragalactic radio sources, and a few of them were associated with nearby galaxies that were abnormal in some way. Various discoveries stimulated significant investment in the construction of radio telescopes, leading to the discovery of many more radio sources outside the galaxy. By determining accurate positions for the radio sources, their optical counterparts could be identified. The nature of the quasars remained a mystery. The similarity between quasars and the nuclei of Seyfert galaxies was reinforced by the discovery in 1968 that the continuum emission of the latter is variable, like that of quasars.
Alvaro De Rújula
- Published in print:
- 2018
- Published Online:
- February 2020
- ISBN:
- 9780198817802
- eISBN:
- 9780191859366
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198817802.003.0032
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
What we know or do not know about dark matter. The evidence for its existence, first found by Fritz Zwicky. The “virial theorem” and the Coma cluster. The rotation curves of galaxies. Galactic ...
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What we know or do not know about dark matter. The evidence for its existence, first found by Fritz Zwicky. The “virial theorem” and the Coma cluster. The rotation curves of galaxies. Galactic dark-matter halos. Gravitational lensing and the May 1919 solar eclipse, a thiumph of General Relativity that propelled Einstein to his fame. The deflection of starlight by the eclipsed Sun. Gravitational lenses, Einstein rings, and Smilie. Gravitational-lensing and evidence for dark matter in the Bullet cluster of galaxies.Less
What we know or do not know about dark matter. The evidence for its existence, first found by Fritz Zwicky. The “virial theorem” and the Coma cluster. The rotation curves of galaxies. Galactic dark-matter halos. Gravitational lensing and the May 1919 solar eclipse, a thiumph of General Relativity that propelled Einstein to his fame. The deflection of starlight by the eclipsed Sun. Gravitational lenses, Einstein rings, and Smilie. Gravitational-lensing and evidence for dark matter in the Bullet cluster of galaxies.
