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".

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.

The nature and essence of Dark Matter and Dark Energy have become the central issue in modern cosmology over the past years. This extensive volume, an outgrowth of a topical and tutorial summer school, has been set up with the aim of constituting an advanced-level, multi-authored textbook which meets the needs of both postgraduate students and young researchers in the fields of modern cosmology and astrophysics.

Advances made by physicists in understanding matter, space, and time and by astronomers in understanding the universe as a whole have closely intertwined the question being asked about the universe at its two extremesâ€"the very large and the very small. This report identifies 11 key questions that have a good chance to be answered in the next decade. It urges that a new research strategy be created that brings to bear the techniques of both astronomy and sub-atomic physics in a cross-disciplinary way to address these questions. The report presents seven recommendations to facilitate the necessary research and development coordination. These recommendations identify key priorities for future scientific projects critical for realizing these scientific opportunities.

'Clear and compact ... It's hard to fault as a brief, easily digestible introduction to some of the biggest questions in the Universe' Giles Sparrow, BBC Four's The Sky at Night , Best astronomy and space books of 2019: 5/5 All the matter and light we can see in the universe makes up a trivial 5 per cent of everything. The rest is hidden. This could be the biggest puzzle that science has ever faced. Since the 1970s, astronomers have been aware that galaxies have far too little matter in them to account for the way they spin around: they should fly apart, but something concealed holds them together. That 'something' is dark matter - invisible material in five times the quantity of the familiar stuff of stars and planets. By the 1990s we also knew that the expansion of the universe was accelerating. Something, named dark energy, is pushing it to expand faster and faster. Across the universe, this requires enough energy that the equivalent mass would be nearly fourteen times greater than all the visible material in existence. Brian Clegg explains this major conundrum in modern science and looks at how scientists are beginning to find solutions to it.

What’s in the dark? Countless generations have gazed up at the night sky and asked this question—the same question that cosmologists ask themselves as they study the universe. The answer turns out to be surprising and rich. The space between stars is filled with an exotic substance called “dark matter” that exerts gravity but does not emit, absorb, or reflect light. The space between galaxies is rife with “dark energy” that creates a sort of cosmic antigravity causing the expansion of the universe to accelerate. Together, dark matter and dark energy account for 95 percent of the content of the universe. News reporters and science journalists routinely talk about these findings using terms that they assume we have a working knowledge of, but do you really understand how astronomers arrive at their findings or what it all means? Cosmologists face a conundrum: how can we study substances we cannot see, let alone manipulate? A powerful approach is to observe objects whose motion is influenced by gravity. Einstein predicted that gravity can act like a lens to bend light. Today we see hundreds of cases of this—instances where the gravity of a distant galaxy distorts our view of a more distant object, creating multiple images or spectacular arcs on the sky. Gravitational lensing is now a key part of the international quest to understand the invisible substance that surrounds us, penetrates us, and binds the universe together. A Ray of Light in a Sea of Dark Matter offers readers a concise, accessible explanation of how astronomers probe dark matter. Readers quickly gain an understanding of what might be out there, how scientists arrive at their findings, and why this research is important to us. Engaging and insightful, Charles Keeton gives everyone an opportunity to be an active learner and listener in our ever-expanding universe. Watch a video with Charles Keeton: Watch video now. (http://www.youtube.com/watch?v=Uc3byXNS1G0).

Introducing the theoretical ideas, observational methods and results in dark energy, this textbook is a thorough introduction to dark energy for graduate courses.