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Books > Science & Mathematics > Astronomy, space & time
"Quantum Gravitation" approaches the subject from the point of view of Feynman path integrals, which provide a manifestly covariant approach in which fundamental quantum aspects of the theory such as radiative corrections and the renormalization group can be systematically and consistently addressed. It is shown that the path integral method is suitable for both perturbative as well as non-perturbative studies, and is already known to offer a framework for the theoretical investigation of non-Abelian gauge theories, the basis for three of the four known fundamental forces in nature. The book thus provides a coherent outline of the present status of the theory gravity based on Feynman s formulation, with an emphasis on quantitative results. Topics are organized in such a way that the correspondence to similar methods and results in modern gauge theories becomes apparent. Covariant perturbation theory are developed using the full machinery of Feynman rules, gauge fixing, background methods and ghosts. The renormalization group for gravity and the existence of non-trivial ultraviolet fixed points are investigated, stressing a close correspondence with well understood statistical field theory models. The final chapter addresses contemporary issues in quantum cosmology such as scale dependent gravitational constants and quantum effects in the early universe."
This book provides an introduction to the physics of interstellar gas in the Galaxy. It deals with the diffuse interstellar medium which supplies a complex environment for exploring the neutral gas content of a galaxy like the Milky Way and the techniques necessary for studying this non-stellar component. After an initial exposition of the phases of the interstellar medium and the role of gas in a spiral galaxy, the authors discuss the transition from atomic to molecular gas. They then consider basic radiative transfer and molecular spectroscopy with particular emphasis on the molecules useful for studying low-density molecular gas. Observational techniques for investigating the gas and the dust component of the diffuse interstellar medium throughout the electromagnetic spectrum are explored emphasizing results from the recent Herschel and Planck missions. A brief exposition on dust in the diffuse interstellar medium is followed by a discussion of molecular clouds in general and high-latitude molecular clouds in particular. Ways of calibrating CO observations with the molecular hydrogen content of a cloud are examined along with the dark molecular gas controversy. High-latitude molecular clouds are considered in detail as vehicles for applying the techniques developed in the book. Given the transient nature of diffuse and translucent molecular clouds, the role of turbulence in the origin and dynamics of these objects is examined in some detail. The book is targeted at graduate students or postdocs who are entering the field of interstellar medium studies.
This book aims at giving the basis of primordial cosmology. The book is self-contained in the sense that all the elements for the derivations of the presented results are given. It can be used as a textbook to study cosmology. It is divided into 3 parts. Part 1 summarizes the fundamentals in theoretical physics needed in cosmology (general relativity, field theory, particle physics). Part 2 describes the standard model of cosmology and includes cosmological solutions of Einstein equations, hot big bang model, cosmological perturbation theory, cosmic microwave background anisotropies, lensing and evidences for dark matter, and inflation. Part 3 describes extensions of this model and opens up to today's research in the field: scalar-tensor theories, supersymetry, the cosmological constant problem and acceleration of the universe, topology of the universe, grand unification and baryogenesis, topological defects and phase transitions, string inspired cosmology including branes and latest developments. The book provides details of all derivations and leads the student up to the level of research articles.
The Sun is nowadays observed using di?erent techniques that provide an almost instantaneous 3-D map of its structure. Of particular interest is the studyofthevariabilityinthesolaroutputproducedbythedissipationofm- netic energy on di?erent spatial and temporal scales - the so-called magnetic activity. The 11-year cycle is the main feature describing this phenomenon. Apart from its intrinsic scienti?c interest, this topic is worth studying because of the interaction of such processes with the terrestrial environment. A ?eet of space and ground-based observatories are currently monitoring the behaviour of our star on a daily basis. However, solar activity varies not only on this decadal time-scale, as has been attested mainly through two methods: (a) records of the number of sunspots observed on the solar surface from 1610, and (b) the records of 14 10 cosmogenic isotopes, such as Cand Be, measured in tree-rings and i- cores, respectively. The study of the long-term behaviour of solar activity may be comp- mented by the study of historical accounts describing phenomena directly or indirectly related to solar activity. Numerous scienti?c and non-scienti?c d- uments have reported these events and we can make use of them as a proxy of solar activity in past times.
This outstanding thesis by Dominic Bowman provides a thorough investigation of long-standing questions as to whether amplitude modulation is astrophysical, whether it offers insights into pulsating stars, and whether simple beating of modes with stable amplitudes is unrecognised because of a lack of frequency resolution. In this thesis, the author studied a uniform sample of 983 delta Scuti stars-the most common type of main-sequence heat engine pulsator-that were observed nearly continuously for 4 years at stunning photometric precision of only a few parts per million by the Kepler space mission. With no mission planned to supersede the Kepler 4-year data set, this thesis will stand as the definitive study of these questions for many years. With revolutionary photometric data from the planet-hunting Kepler space mission, asteroseismic studies have been carried out on many hundreds of main-sequence solar-type stars and about 10,000 red giants. It is easy to understand why those stochastically driven stars have highly variable amplitudes. Over much of the rest of the Hertzsprung-Russell (HR) diagram, stellar pulsations are driven by heat mechanisms, which are much more regular than the stochastic driving in solar-like pulsators. Yet for decades, amplitude and frequency modulation of pulsation modes have been observed in almost all types of heat-driven pulsating stars. The author shows that the amplitude and frequency modulation are astrophysical, and he has investigated their implications and prospects to provide new insights into the delta Scuti stars and the many other types of heat-engine pulsators across the HR diagram.
This volume aims to make Stephen of Pisa and Antioch's work on the celestial sciences accessible to a wider readership, providing not just the text but a translation and introduction as well. The edition is based on the only known manuscript of the Liber Mamonis, MS Cambrai, Mediatheque d'Agglomeration, A 930. It is split into two parts: the first provides an extensive introduction to Stephen and his work, while the second features the edition and translation. A comprehensive glossary and collection of photographs of plates are also included.
In The Earth as a Distant Planet, the authors become external observers of our solar system from a distance and try to determine how one can understand how Earth, the third in distance to the central star, is essentially unique and capable of sustaining life. The knowledge gained from this original perspective is then applied to the search for other planets outside the solar system, or exoplanets. Since the discovery in 1992 of the first exoplanet, the number of planet detections has increased exponentially and ambitious missions are already being planned for the future. The exploration of Earth and the rest of the rocky planets are Rosetta stones in classifying and understanding the multiplicity of planetary systems that exist in our galaxy. In time, statistics on the formation and evolution of exoplanets will be available and will provide vital information for solving some of the unanswered questions about the formation, as well as evolution of our own world and solar system. Special attention is paid to the biosignatures (signs of life) detectable in the Earth's reflected spectra and the search for life in the universe. The authors are experts on the subject of extrasolar planets. They provide an introductory but also very much up-to-date text, making this book suitable for researchers and for advanced students in astronomy and astrophysics.
The Workshop "Science with the VLT in the ELT Era" held in Garching from 8th to 12th October 2007 was organised by ESO, with support from its Scienti c and Technical Committee, to provide a forum for the astronomical community to debate the long term future of ESO's Very Large Telescope (VLT) and its interferometric mode (VLTI). In particular it was considered useful for future planning to evaluate how its science use may evolve over the next decade due to competition and/or synergy with new facilities such as ALMA, JWST and, hopefully, at least one next generation 30-40 m extremely large telescope whose acronym appears in the title to symbolise this wider context. These discussions were also held in the fresh light of the Science Vision recently developed within ASTRONET as the rst step towards a 20 year plan for implementing astronomical facilities-the rst such attempt within Europe. Speci c ideas and proposals for new, second generation VLT/I instruments were also solicited following a tradition set by several earlier Workshops held since the start of the VLT development. The programme consisted of invited talks and reviews and contributed talks and posters. Almost all those given are included here although, unfortunately not the several lively but constructive discussion sessions.
This prize-winning Ph.D. thesis by Chris Harrison adopts a multi-faceted approach to address the lack of decisive observational evidence, utilising large observational data sets from several world-leading telescopes. Developing several novel observational techniques, Harrison demonstrated that energetic winds driven by Active Galactic Nuclei (AGN) are found in a large number of galaxies, with properties in agreement with model predictions. One of the key unsolved problems in astrophysics is understanding the influence of AGN, the sites of growing supermassive black holes, on the evolution of galaxies. Leading theoretical models predict that AGN drive energetic winds into galaxies, regulating the formation of stars. However, until now, we have lacked the decisive observational evidence to confirm or refute these key predictions. Careful selection of targets allowed Harrison, to reliably place these detailed observations into the context of the overall galaxy population. However, in disagreement with the model predictions, Harrison showed that AGN have little global effect on star formation in galaxies. Theoretical models are now left with the challenge of explaining these results.
Humans evolved when the Sun was in the great void of the Local Bubble. The Sun entered the present environment of interstellar clouds only during the late Quaternary. Astronomical data reveal these long and short term changes in our galactic environment. Theoretical models then tell us how these changes affect interplanetary particles, planetary magnetospheres, and the Earth itself. Cosmic rays leave an isotopic signature in the paleoclimate record that helps trace the solar journey through space. This volume lays the foundation for an interdisciplinary study of the influence of interstellar material on the solar system and Earth as we travel through the Milky Way Galaxy.
Cosmology and theology share a long held relationship with one another, explaining as they do the constitution of the World and the interaction of forces. The author explores the history of this relationship, from ancient pre-scientific and theological, explanations through to contemporary science and philosophy. In this history, a particular problem is highlighted by the author: the prevalence of dualism; from Aristotelian philosophy to modern mechanistic conceptions, many of these accounts presume a sharp, absolute dichotomy between matter and spirit, and the material world and the divine. Increasingly, dualistic conceptions are called into question by contemporary science, theology, and philosophy. The author argues that a particular trajectory stemming from Greek Heraclitian and Platonic philosophy to non-orthodox and early Christian theologies provides a fruitful resource for contemporary discussions. This is the Logos theology and its attendant language of light. The author brings this tradition into dialogue with contemporary science and theology to construct an integrative account.
In this book, the author leads the reader, step by step and without any advanced mathematics, to a clear understanding of the foundations of modern elementary particle physics and cosmology. He also addresses current and controversial questions on topics such as string theory. The book contains gentle introductions to the theories of special and general relativity, and also classical and quantum field theory. The essential aspects of these concepts are understood with the help of simple calculations; for example, the force of gravity as a consequence of the curvature of the space-time. Also treated are the Big Bang, dark matter and dark energy, as well as the presently known interactions of elementary particles: electrodynamics, the strong and the weak interactions including the Higgs boson. Finally, the book sketches as yet speculative theories: Grand Unification theories, supersymmetry, string theory and the idea of additional dimensions of space-time. Since no higher mathematical or physics expertise is required, the book is also suitable for college and university students at the beginning of their studies. Hobby astronomers and other science enthusiasts seeking a deeper insight than can be found in popular treatments will also appreciate this unique book.
This groundbreaking volume provides an up-to-date, accessible guide to Sanskrit astronomical tables and their analysis. It begins with an overview of Indian mathematical astronomy and its literature, including table texts, in the context of history of pre-modern astronomy. It then discusses the primary mathematical astronomy content of table texts and the attempted taxonomy of this genre before diving into the broad outlines of their representation in the Sanskrit scientific manuscript corpus. Finally, the authors survey the major categories of individual tables compiled in these texts, complete with brief analyses of some of the methods for constructing and using them, and then chronicle the evolution of the table-text genre and the impacts of its changing role on the discipline of Sanskrit jyotisa. There are also three appendices: one inventories all the identified individual works in the genre currently known to the authors; one provides reference information about the details of all the notational, calendric, astronomical, and other classification systems invoked in the study; and one serves as a glossary of the relevant Sanskrit terms.
In 1942, the logician Kurt Godel and Albert Einstein became close friends; they walked to and from their offices every day, exchanging ideas about science, philosophy, politics, and the lost world of German science. By 1949, Godel had produced a remarkable proof: "In any universe described by the Theory of Relativity, time cannot exist," Einstein endorsed this result reluctantly but he could find no way to refute it, since then, neither has anyone else. Yet cosmologists and philosophers alike have proceeded as if this discovery was never made. In "A World Without Time," Palle Yourgrau sets out to restore Godel to his rightful place in history, telling the story of two magnificent minds put on the shelf by the scientific fashions of their day, and attempts to rescue the brilliant work they did together.
Meteorites are natural objects that have fallen from space to the Earth's surface. Once considered bad omens, they are now recognised as a unique window onto the processes that forged the formation of the solar system 4,570 million years ago. They reveal how impacts have shaped and modified planets, asteroids and moons; and they even contain evidence of astrophysical phenomena that occurred long before our solar system was born. In Meteorites, leading experts from the Natural History Museum, London provide a compelling and cutting edge introduction to the evolving science of meteoritics. They reveal what meteorites are, where they are most likely to be found, and the type of celestial bodies that they hail from. The book contains all the latest information on key meteorite falls and considers some of the big questions that still remain - such as whether our solar system is unusual in creating a planet that supports life, and if it is likely we will find complex life elsewhere. With a mix of photographs, diagrams and maps, Meteorites is essential reading for all those with an interest in the nature of our solar system.
Based on material delivered at several summer schools, this book is the first comprehensive textbook at the graduate level encompassing all aspects associated with the emerging field of astrobiology. Volume II gathers another set of extensive lectures covering
topics so diverse as the formation and the distribution of elements
in the universe, the concept of habitability from both the
planetologists' and the biologists' point of view and artificial
life. The contributions are held together by the common goal to
understand better the origin of life, its evolution and possible
existence outside the Earth's realm.
This volume shows how collective magnetic excitations determine most of the magnetic properties of itinerant electron magnets. Previous theories were mainly restricted to the Curie-Weiss law temperature dependence of magnetic susceptibilities. Based on the spin amplitude conservation idea including the zero-point fluctuation amplitude, this book shows that the entire temperature and magnetic field dependence of magnetization curves, even in the ground state, is determined by the effect of spin fluctuations. It also shows that the theoretical consequences are largely in agreement with many experimental observations. The readers will therefore gain a new comprehensive perspective of their unified understanding of itinerant electron magnetism.
This is the largest and most comprehensive atlas of the universe ever created for amateur astronomers. With finder charts of unprecedented detail, in both normal and mirror-image views, and an extensive list of 14,000 objects, it provides a detailed observing guide for almost any practical amateur astronomer, up to the most advanced. Spanning some 3,000 pages, this is a project that is possible only on CD-ROM. The CD-R pages are extensively indexed and referenced for quick location of objects. The accompanying book gives an introduction to the Atlas, showcases the maps, describes the CD-R content and organization, and includes various appendices.
This volume contains the proceedings of possibly the last conference ever on integral-field spectroscopy. The contributors, noted authorities in the field, focus on the scientific questions that can be answered with integral-field spectroscopy, ranging from solar system studies all the way to high redshift surveys. Overall readers get a state-of-the-science review of astronomical 3D spectroscopy.
The central aim of the "Sunrise "project is to understand the structure and dynamics of the magnetic field in the solar atmosphere. The magnetic field is the source of solar activity, controls the space environment of the Earth and causes the variability of solar irradiance, which may be a significant driver of long-term changes of the terrestrial climate. Interacting with the convective plasma flow, the magnetic field in the solar photosphere develops intense field concentrations on scales below 100 km, which are crucial for the dynamics and energetics of the whole solar atmosphere. These spatial scales cannot be studied systematically from the ground because of image distortions due to atmospheric turbulence. The balloon-borne "Sunrise" telescope has, for the first time, provided measurements of the magnetic structure of the solar atmosphere on its intrinsic spatial and temporal scales. The book gives an overview about the instrumentation and the successful flight in 2009.
Awarded the American Astronomical Society (AAS) Rodger Doxsey Travel Prize, and with a foreword by thesis supervisor Professor Shardha Jogee at the University of Texas at Austin, this thesis discusses one of the primary outstanding problems in extragalactic astronomy: how galaxies form and evolve. Galaxies consist of two fundamental kinds of structure: rotationally supported disks and spheroidal/triaxial structures supported by random stellar motions. Understanding the balance between these galaxy components is vital to comprehending the relative importance of the different mechanisms (galaxy collisions, gas accretion and internal secular processes) that assemble and shape galaxies. Using panchromatic imaging from some of the largest and deepest space-based galaxy surveys, an empirical census of galaxy structure is made for galaxies at different cosmic epochs and in environments spanning low to extremely high galaxy number densities. An important result of this work is that disk structures are far more prevalent in massive galaxies than previously thought. The associated challenges raised for contemporary theoretical models of galaxy formation are discussed. The method of galaxy structural decomposition is treated thoroughly since it is relevant for future studies of galaxy structure using next-generation facilities, like the James Webb Space Telescope and the ground-based Giant Magellan Telescope with adaptive optics.
The Square Kilometre Array (SKA) Project is a global project to design and c- struct a revolutionary new radio telescope with of order 1 million square meters of collecting area in the wavelength range from3mto1cm.It will have two - ders of magnitude greater sensitivity than current telescopes and an unprecedented large instantaneous ?eld-of-view. These capabilities will ensure the SKA will play a leading role in solving the major astrophysical and cosmological questions of the day (see the science case at www.skatelescope.org/pages/page astronom.htm). The SKA will complement major ground- and space-based astronomical facilities under construction or planned in other parts of the electromagnetic spectrum (e.g. ALMA, JWST, ELT, XEUS,...). The current schedule for the SKA foresees a decision on the SKA site in 2006, a decisiononthedesignconceptin2009,constructionofthe?rstphase(international path?nder)from2010to2013,andconstructionofthefullarrayfrom2014to2020. The cost is estimated to be about 1000 M . TheSKAProjectcurrentlyinvolves45institutesin17countries,manyofwhich are involved in nationally- or regionally-funded state-of-the-art technical devel- ments being pursued ahead of the 2009 selection of design concept. This Special Issue of Experimental Astronomy provides a snapshot of SKA engineering act- ity around the world, and is based on presentations made at the SKA meeting in Penticton,BC,CanadainJuly2004.Topicscoveredincludeantennaconcepts,so- ware, signal transport and processing, radio frequency interference mitigation, and reports on related technologies in other radio telescopes now under construction. Further information on the project can be found at www.skatelescope.org.
Based on extensive primary sources, many never previously translated into English, this is the definitive account of the discovery of Pallas as it went from being classified as a new planet to reclassification as the second of a previously unknown group of celestial objects. Cunningham, a dedicated scholar of asteroids, includes a large set of newly translated correspondence as well as the many scientific papers about Pallas in addition to sections of Schroeter's 1805 book on the subject. It was Olbers who discovered Pallas, in 1802, the second of many asteroids that would be officially identified as such. From the Gold Medal offered by the Paris Academy to solve the mystery of Pallas' gravitational perturbations to Gauss' Pallas Anagram, the asteroid remained a lingering mystery to leading thinkers of the time. Representing an intersection of science, mathematics, and philosophy, the puzzle of Pallas occupied the thoughts of an amazing panorama of intellectual giants in Europe in the early 1800s. |
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