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

An advanced text for senior undergraduates, graduate students and physical scientists in fields outside cosmology. This is a self-contained book focusing on the linear theory of the evolution of density perturbations in the universe, and the anisotropiesin the cosmic microwave background.

The Extravagant Universe tells the story of a remarkable adventure of scientific discovery. One of the world's leading astronomers, Robert Kirshner, takes readers inside a lively research team on the quest that led them to an extraordinary cosmological discovery: the expansion of the universe is accelerating under the influence of a dark energy that makes space itself expand. In addition to sharing the story of this exciting discovery, Kirshner also brings the science up-to-date in a new epilogue. He explains how the idea of an accelerating universe--once a daring interpretation of sketchy data--is now the standard assumption in cosmology today. This measurement of dark energy--a quality of space itself that causes cosmic acceleration--points to a gaping hole in our understanding of fundamental physics. In 1917, Einstein proposed the "cosmological constant" to explain a static universe. When observations proved that the universe was expanding, he cast this early form of dark energy aside. But recent observations described first-hand in this book show that the cosmological constant--or something just like it--dominates the universe's mass and energy budget and determines its fate and shape. Warned by Einstein's blunder, and contradicted by the initial results of a competing research team, Kirshner and his colleagues were reluctant to accept their own result. But, convinced by evidence built on their hard-earned understanding of exploding stars, they announced their conclusion that the universe is accelerating in February 1998. Other lines of inquiry and parallel supernova research now support a new synthesis of a cosmos dominated by dark energy but also containing several forms of dark matter. We live in an extravagant universe with a surprising number of essential ingredients: the real universe we measure is not the simplest one we could imagine.

Dark Matter, Dark Energy and Dark Gravity make life possible!This book for the lay reader provides a summary of the latest astrophysical observational results and theoretical insights into what we know and what we hope to learn about dark matter, dark energy, and dark gravity.How did the profound beauty of our Earth, our Solar System, our Milky Way galaxy and indeed our universe unfold? Dark matter, dark energy, and dark gravity have made all the difference in how the universe has developed, and have been key to creating the overall environment that makes life possible. We have only recently developed the ability to begin unlocking their secrets, thus providing a deeper insight into how a universe of our type is possible. It seems that because of dark matter, dark energy and dark (weak) gravity, our universe has the right attributes for the development of complex structure and the evolution of intelligent life that can engage in the quest to understand our world. These "dark" or more hidden attributes of the cosmos have very good outcomes.In particular, the existence of dark matter makes it easier to form complex structures, including galaxies, stars and planets through gravitational collapse of denser regions of the universe. Planets are the most suitable abodes for the development of life. Dark energy acts to extend the lifetime of the universe by counteracting gravity and driving continued expansion of the universe.Even as far back as the 1930s there has been evidence that most of the matter in the universe was not visible via electromagnetic radiation (optical light, radio waves, etc.). By the last few decades of the 20th century, the case for a considerable amount of this dark matter was very strong. It is the second largest contributor to the total mass-energy of the universe. We don't know what it is and there are various candidates to explain it; nevertheless we see the gravitational effects of dark matter everywhere on the largest scales. Recent observational results indicate that dark matter dominates by a factor of 6 relative to the ordinary matter that makes up stars, planets, and living things.We now know that the major contributor to the mass-energy of the universe is not the substantial dark matter, but the 'newer' so-called dark energy. Dark energy acts to some extent as a negative gravity, and for the last several billion years has driven the expansion of the universe to a faster and faster pace, overcoming even the gravitational effect of dark matter. We have a general idea that it is the irreducible energy found in every volume of space, even in the absence of matter - in the vacuum. We don't understand why it takes the value that it does, one that is small in quantum particle physics terms, but nevertheless is of great significance on the large cosmological scale of the universe. The third important aspect to consider is not a mass-energy component, but the nature of gravity and space-time. The big question here is - why is gravity so relatively weak, as compared to the other 3 forces of nature? These 3 forces are the electromagnetic force, the strong nuclear force, and the weak nuclear force. Gravity is different - it has a dark or hidden side. It may very well operate in extra dimensions beyond the normal 4 dimensions of space-time that we can observe. This is what we mean in this book by "dark gravity".

Beginning with basic facts about the observable universe, this book reviews the complete range of topics that make up a degree course in cosmology and particle astrophysics. The book is self-contained - no specialised knowledge is required on the part of the reader, apart from undergraduate math and physics. This paperback edition targets students of physics, astrophysics and cosmology from advanced undergraduate to early graduate level.

This book brings together reviews from leading international authorities on the developments in the study of dark matter and dark energy, as seen from both their cosmological and particle physics side. Studying the physical and astrophysical properties of the dark components of our Universe is a crucial step towards the ultimate goal of unveiling their nature. The work developed from a doctoral school sponsored by the Italian Society of General Relativity and Gravitation. The book starts with a concise introduction to the standard cosmological model, as well as with a presentation of the theory of linear perturbations around a homogeneous and isotropic background. It covers the particle physics and cosmological aspects of dark matter and (dynamical) dark energy, including a discussion of how modified theories of gravity could provide a possible candidate for dark energy. A detailed presentation is also given of the possible ways of testing the theory in terms of cosmic microwave background, galaxy redshift surveys and weak gravitational lensing observations. Included is a chapter reviewing extensively the direct and indirect methods of detection of the hypothetical dark matter particles. Also included is a self-contained introduction to the techniques and most important results of numerical (e.g. N-body) simulations in cosmology. " This volume will be useful to researchers, PhD and graduate students in Astrophysics, Cosmology Physics and Mathematics, who are interested in cosmology, dark matter and dark energy.

Thoroughly revised and updated introduction to past and present cosmological theory.