As the structures in our Universe are mapped out on ever larger scales, and with increasing detail, the use of inhomogeneous models is becoming an essential tool for analyzing and understanding them. This book reviews a number of important developments in the application of inhomogeneous solutions of Einstein's field equations to cosmology. It shows how inhomogeneous models can be employed to study the evolution of structures such as galaxy clusters and galaxies with central black holes, and to account for cosmological observations like supernovae dimming, the cosmic microwave background, baryon acoustic oscillations or the dependence of the Hubble parameter on redshift within classical general relativity. Whatever `dark matter' and `dark energy' turn out to be, inhomogeneities exist on many scales and need to be investigated with all appropriate methods. This book is of great value to all astrophysicists and researchers working in cosmology, from graduate students to academic researchers.

Based on lectures given in honour of Stephen Hawking's sixtieth birthday, this book comprises contributions from some of the world's leading theoretical physicists. It begins with a section containing chapters by successful scientific popularisers, bringing to life both Hawking's work and other exciting developments in physics. The book then goes on to provide a critical evaluation of advanced subjects in modern cosmology and theoretical physics. Topics covered include the origin of the universe, warped spacetime, cosmological singularities, quantum gravity, black holes, string theory, quantum cosmology and inflation. As well as providing a fascinating overview of the wide variety of subject areas to which Stephen Hawking has contributed, this book represents an important assessment of prospects for the future of fundamental physics and cosmology.

"If you buy just one guide...you won't do better than this" BBC Sky at Night Magazine "I will continue to enjoy 'Philip's Stargazing' as the months go by" Helen Sharman, Astronaut "Very useful indeed" Chris Lintott, Sky at Night presenter Now including the top astronomical places to visit, star festivals and the latest on star parties in Britain and Ireland, the new 2023 edition is totally up-to-date for exploring the wonder of the night skies, month-by-month and day-by-day. Whether you're a seasoned astronomer or just starting out, Philip's Stargazing 2023 is the only book you'll need. Compiled by experts and specially designed for easy and daily use, Stargazing 2023 acts as a handily illustrated and comprehensive companion. - 12 updated sky charts for year-round astronomical discovery - Month-to-Month information. Daily Moon Phase Calendar, highlighting special lunar events throughout the year - Planet Watch for ideal viewing days in 2023 - The best places to experience Dark Skies, along with the latest on Star Festivals and Star Parties - Top places to visit for astronomical insights - Expert advice and insight throughout from internationally renowned Prof Nigel Henbest - The latest on electronic telescopes from expert Robin Scagell - Complete calendar of major astronomical events, including the Top 20 Sky Sights of 2023 - Jargon Buster, explaining common or confusing terms - The planets' movements explained from solar and lunar eclipses to meteor showers and comets

This book describes what will ultimately happen to the contents of the universe. To understand the universe in the far future, we must first describe its present state and structure on the grand scale, and how its present properties arose. Dr Islam explains these topics in an accessible way in the first part of the book. From this background he speculates about the future evolution of the universe and predicts the major changes that will occur. The author has largely avoided mathematical formalism and therefore the book is well suited to general readers with a modest background knowledge of physics and astronomy.

From a planet with a hexagonal storm to the home of the Solar System's largest volcano, our neighbouring bodies are unique and fascinating places. Where else would you find somewhere with days longer than its years? Humanity's understanding of planets has changed drastically since ancient times when early astronomers mistook the lights they saw in the sky for wandering stars. We've come a long way since then, but there's still so much we don't know. Could there be life on Mars? How many planets exist outside the Solar System? Is there another 'Earth' out there? And why can't we call Pluto a planet anymore? Discover more in this essential guide to planets in the Solar System and beyond by astronomer Dr Emily Drabek-Maunder of Royal Observatory Greenwich.

This book explains hyperspace and multidimensional geometries in an effort to help readers to manipulate, visualize, and think about the higher spatial dimensions that all serious physical theories since relativity have required. This book alternates sections explaining the science with a fictional story line that exemplifies, comments on, and helps to clarify the science. The book also features a number of appendices, including annotated guides to the literature and to relevant science fiction, further commentary on the mathematics of hyperspace, questions and puzzles, and source code for modeling hyperspace. The book has the goal to explain the science of hyperspace accurately, but it is light and playful in its approach.

Cosmology, the study of the universe as a whole, has become a precise physical science, the foundation of which is our understanding of the cosmic microwave background radiation (CMBR) left from the big bang. The story of the discovery and exploration of the CMBR in the 1960s is recalled for the first time in this collection of 44 essays by eminent scientists who pioneered the work. Two introductory chapters put the essays in context, explaining the general ideas behind the expanding universe and fossil remnants from the early stages of the expanding universe. The last chapter describes how the confusion of ideas and measurements in the 1960s grew into the present tight network of tests that demonstrate the accuracy of the big bang theory. This book is valuable to anyone interested in how science is done, and what it has taught us about the large-scale nature of the physical universe.

There's a whole universe out there... Imagine you had a spacecraft capable of travelling through interstellar space. You climb in, blast into orbit, fly out of the solar system and keep going. Where do you end up, and what do you see along the way? The answer is: mostly nothing. Space is astonishingly, mind-blowingly empty. As you travel through the void between galaxies your spaceship encounters nothing more exciting than the odd hydrogen molecule. But when it does come across something more exotic: wow! First and most obviously, stars and planets. Some are familiar from our own backyard: yellow suns, rocky planets like Mars, gas and ice giants like Jupiter and Neptune. But there are many more: giant stars, red and white dwarfs, super-earths and hot Jupiters. Elsewhere are swirling clouds of dust giving birth to stars, and infinitely dense regions of space-time called black holes. These clump together in the star clusters we call galaxies, and the clusters of galaxies we call... galaxy clusters. And that is just the start. As we travel further we encounter ever more weird, wonderful and dangerous entities: supernovas, supermassive black holes, quasars, pulsars, neutron stars, black dwarfs, quark stars, gamma ray bursts and cosmic strings. A Journey Through The Universe is a grand tour of the most amazing celestial objects and how they fit together to build the cosmos. As for the end of the journey - nobody knows. But getting there will be fun. ABOUT THE SERIES New Scientist Instant Expert books are definitive and accessible entry points to the most important subjects in science; subjects that challenge, attract debate, invite controversy and engage the most enquiring minds. Designed for curious readers who want to know how things work and why, the Instant Expert series explores the topics that really matter and their impact on individuals, society, and the planet, translating the scientific complexities around us into language that's open to everyone, and putting new ideas and discoveries into perspective and context.

In the years between 1900 and 1931 astronomers witnessed three startling changes in their view of the Universe. First, the accepted value of the size of the star system, which increased by a factor of ten; secondly, evidence forced the acceptance of the fact that there are other star systems beyond our own Galaxy; and lastly, that observation of these external galaxies disclosed the expansion of the Universe. This book, originally published in 1982, describes and explains in detail these shifts in opinion, considering them in the light of theories and ideas on the nature of the Universe, were current at the beginning of the twentieth century. Archive material is used to provide major interpretations of several of the processes and events associated with these shifts such as the 'Great Debate' between Harlow Shapley and H. D. Curtis in 1920 on 'The scale of the Universe'. This book with be of interest to professional and amateur astronomers as well as historians of science.

Manolis Plionis & Spiros Cotsakis plionis@sapfo. astro. noa. gr skot@aegean. gr Since the dawn of human civilisation natural phenomena have been subject to observation and investigation by the humans who initially ascribed to them 'divine' powers. Gods of 'good' and 'evil' werecreatedaccording to the useful- ness or notofsuch unexplained, atthetime, phenomena. Astheir understanding of the world developed and deepened, the divine powers, religious beliefs, su- perstitions and mysticism gave their place to the knowledge, limited that it may be, of physical reality. However, many issues have been and still are out of grasp of human understanding. These issues have always been at the center of philosophical, theological, and more recently, scientific debate. It is to us incredible that many of the conclusions concerning the true scientific explanation of the external world, to which the ancient Greeks arrived purely on the basis of abstract thought, came so near to modem scientific ideas and also form the basis of modem science. We cannot but stand with amazement at the original thoughts of Archimedes who, among his many extraordinary achieve- ments in mathematics and physics, calculated (cf. TheSandReckoner) the mass density of the observable universe and came up with a figure that is in complete agreement with current estimates coming from observational cosmology.

Modern physics rests on two fundamental building blocks: general relativity and quantum theory. General relativity is a geometric interpretation of gravity while quantum theory governs the microscopic behaviour of matter. Since matter is described by quantum theory which in turn couples to geometry, we need a quantum theory of gravity. In order to construct quantum gravity one must reformulate quantum theory on a background independent way. Modern Canonical Quantum General Relativity provides a complete treatise of the canonical quantisation of general relativity. The focus is on detailing the conceptual and mathematical framework, on describing physical applications and on summarising the status of this programme in its most popular incarnation, called loop quantum gravity. Mathematical concepts and their relevance to physics are provided within this book, which therefore can be read by graduate students with basic knowledge of quantum field theory or general relativity.

The immensity of the cosmos, the richness of the Universe, the limits of space and time: these are the themes of Cosmic Odyssey, which takes the reader on imaginary journeys through the past, present and future of our universe.

What are you? Obviously, you are a person with human ancestors that can be plotted on a family tree, but you have other identities as well. According to evolutionary biologists, for example, you are a member of the species Homo sapiens. To a microbiologist, though, you are a collection of cells, each of which has its own cellular ancestry. A geneticist might point out that besides these identities, you can be understood as a gene-replication machine, which can be plotted on a "genetic tree." Finally a physicist will give a rather different answer to the identity question: you can be understood as a collection of atoms, each of which has a very long history. Some have been around since the Big Bang, and others are the result of nuclear fusion that took place within a star. Not only that, but most of your atoms belonged to other living things before joining you. From your atoms' point of view, then, you are just a way station on a multibillion-year-long journey. You: A Natural History offers a multi-disciplinary investigation of your hyper-extended family tree, going all the way back to the Big Bang. And while your family tree may contain surprises, your hyper-extended history contains some truly amazing stories. As the result of learning more about who and what you are, and about how you came to be here, you will likely see the world around you with fresh eyes. You will also become aware of all the one-off events that had to take place for your existence to be possible: stars had to explode, the earth had to be hit 4.5 billion years ago by a planetesimal and 65 million years ago by an asteroid, microbes had to engulf microbes, the African savanna had to undergo climate change, and of course, any number of your direct ancestors had to meet and mate. It is difficult, on becoming aware of just how contingent your own existence is, not to feel very lucky to be part of our universe.

Cosmic Perspectives is a collection of essays that details modern cosmology and its relationship to the development of human civilization. Written by leading astronomers, cosmologists and historians, these fourteen essays cover a wide range of subjects. These include the place of astronomy in China, frontiers in cosmology, the dark matter problem and the origin of life. This is an engaging collection of facts, written in nontechnical language, which encourages the reader to explore the scientific heritage of various cultures, the current problems of observational astronomy, the unsolved mysteries of evolution and the use of astronomy in fiction.

Simple chemistry governs a host of the exotic objects that populate our cosmos. For example, molecules in the early Universe acted as natural temperature regulators, keeping the primordial gas cool and, in turn, allowing galaxies and stars to form. What are the tools of the trade for the cosmic chemist and what can they teach us about the Universe we live in? These are the questions answered in this engaging and informative guide--the first book for nonspecialists on molecular astrophysics. In clear, nontechnical terms, and without formal mathematics, Hartquist and Williams show how to study and understand the behavior of molecules in a host of astronomical situations. Readers will learn about the secretive formation of stars deep within interstellar clouds; the origin of our own solar system; the cataclysmic deaths of many massive stars that explode as supernovae; and the hearts of active galactic nuclei, the most powerful objects in the universe. This book provides an accessible introduction to a wealth of astrophysics, and an understanding of how cosmic chemistry allows the investigation of many of the most exciting questions concerning astronomy today.

What are the mysterious numbers that unlock the secrets of the universe? In Fantastic Numbers and Where to Find Them, leading theoretical physicist and YouTube star Antonio Padilla takes us on an irreverent cosmic tour of nine of the most extraordinary numbers in physics. These include Graham's number, which is so large that if you thought about it in the wrong way, your head would collapse into a singularity; TREE(3), whose finite value could never be reached before the universe reset itself; and 10^{-120}, which measures the desperately unlikely balance of energy the universe needs to exist. . . Leading us down the rabbit hole to the inner workings of reality, Padilla demonstrates how these unusual numbers are the key to unlocking such mind-bending phenomena as black holes, entropy and the problem of the cosmological constant, which shows that our two best ways of understanding the universe contradict one another. Combining cutting-edge science with an entertaining cosmic quest, Fantastic Numbers and Where to Find Them is an electrifying, head-twisting guide to the most fundamental truths of the universe.

Physical phenomena in astrophysics and cosmology involve gravitational collapse in a fundamental way. The final fate of a massive star when it collapses under its own gravity at the end of its life cycle is one of the most important questions in gravitation theory and relativistic astrophysics, and is the foundation of black hole physics. General relativity predicts that continual gravitational collapse gives rise to a space-time singularity. Quantum gravity may take over in such regimes to resolve the classical space-time singularity. This book investigates these issues, and shows how the visible ultra-dense regions arise naturally and generically as an outcome of dynamical gravitational collapse. It will be of interest to graduate students and academic researchers in gravitation physics, fundamental physics, astrophysics, and cosmology. It includes a detailed review of recent research into gravitational collapse, and several examples of collapse models are investigated in detail.

This highly interdisciplinary 2007 book highlights many of the ways in which chemistry plays a crucial role in making life an evolutionary possibility in the universe. Cosmologists and particle physicists have often explored how the observed laws and constants of nature lie within a narrow range that allows complexity and life to evolve and adapt. Here, these anthropic considerations are diversified in a host of new ways to identify the most sensitive features of biochemistry and astrobiology. Celebrating the classic 1913 work of Lawrence J. Henderson, The Fitness of the Environment for Life, this book looks at the delicate balance between chemistry and the ambient conditions in the universe that permit complex chemical networks and structures to exist. It will appeal to a broad range of scientists, academics, and others interested in the origin and existence of life in our universe.

The standard cosmological picture of our Universe emerging from a 'big bang' leaves open many fundamental questions which string theory, a unified theory of all forces of nature, should be able to answer. This 2007 text was the first dedicated to string cosmology, and contains a pedagogical introduction to the basic notions of the subject. It describes the possible scenarios suggested by string theory for the primordial evolution of our Universe. It discusses the main phenomenological consequences of these scenarios, stresses their differences from each other, and compares them to the more conventional models of inflation. The book summarises over 15 years of research in this field and introduces advances. It is self-contained, so it can be read by astrophysicists with no knowledge of string theory, and high-energy physicists with little understanding of cosmology. Detailed and explicit derivations of all the results presented provide a deeper appreciation of the subject.

The lectures that four authors present in this volume investigate core topics related to the accelerated expansion of the Universe. Accelerated expansion occured in the ?36 very early Universe - an exponential expansion in the in ationary period 10 s after the Big Bang. This well-established theoretical concept had rst been p- posed in 1980 by Alan Guth to account for the homogeneity and isotropy of the observable universe, and simultaneously by Alexei Starobinski, and has since then been developed by many authors in great theoretical detail. An accelerated expansion of the late Universe at redshifts z< 1 has been disc- ered in 1998; the expansion is not slowing down under the in uence of gravity, but is instead accelerating due to some uniformly distributed, gravitationally repulsive substance accounting for more than 70% of the mass-energy content of the U- verse, which is now known as dark energy. Its most common interpretation today is given in terms of the so-called CDM model with a cosmological constant .

What will happen to the near-Earth space environment? How can we ensure the survival of future scientific, commercial and military satellites and space stations? This book addresses the questions that must be asked as debris in space around the Earth--from dust particles to rocket casings, and even radioactive materials--becomes a critical problem. In this volume, many specialists from around the world address the issues, problems, and policies concerned with the preservation of near-Earth space. Their articles cover the technical aspects, and the economic and legal issues concerned, including the enforcement and monitoring of international agreements and the resolution of disputes. This clearly written and well illustrated survey offers the professional and concerned nonspecialist an authoritative and comprehensive review of the problems with and solutions to space debris.

From a physicist at the top of his field comes this rigorous yet accessible book that takes us back in time to before the birth of the universe.

Between the years 1890 and 1924, the dominant view of the universe suggested a cosmology largely foreign to contemporary ideas. First, astronomers believed they had confirmed that the sun was roughly in the centre of the Milky Way galaxy. Second, considerable evidence indicated that the size of the galaxy was only about one-third the value now accepted by today's astronomers. Third, it was thought that interstellar space was completely transparent, that there was no absorbing material between the stars. Fourth, astronomers believed that the universe was composed of numerous star systems comparable to the Milky Way galaxy. The method that provided this picture and came to dominate cosmology was 'statistical' in nature, because it was based on the counts of stars and their positions, motions, brightnesses and stellar spectra. Professor Paul describes the rise of this statistical cosmology in light of developments in nineteenth-century astronomy and explains how this cosmology set the stage for many of the most significant developments of twentieth-century astronomy.

Right now, you are orbiting a black hole. The Earth orbits the Sun, and the Sun orbits the centre of the Milky Way: a supermassive black hole, the strangest and most misunderstood phenomenon in the galaxy. In A Brief History of Black Holes, the award-winning University of Oxford researcher Dr Becky Smethurst charts five hundred years of scientific breakthroughs in astronomy and astrophysics. She takes us from the earliest observations of the universe and the collapse of massive stars, to the iconic first photographs of a black hole and her own published findings. A cosmic tale of discovery, Becky explains why black holes aren't really 'black', that you never ever want to be 'spaghettified', how black holes are more like sofa cushions than hoovers and why, beyond the event horizon, the future is a direction in space rather than in time. Told with humour and wisdom, this captivating book describes the secrets behind the most profound questions about our universe, all hidden inside black holes. 'A jaunt through space history . . . with charming wit and many pop-culture references' - BBC Sky At Night Magazine