The Shadow Of Black Holes

This book introduces an analytic method to describe the shadow of black holes. As an introduction, it presents a survey of the attempts to observe the shadow of galactic black holes. Based on a detailed discussion of the Plebański–Demiański class of space-times, the book derives analytical formulas for the photon regions and for the boundary curve of the shadow as seen by an observer in the domain of outer communication. It also analyzes how the shadow depends on the motion of the observer. For all cases, the photon regions and shadows are visualized for various values of the parameters. Finally, it considers how the analytical formulas can be used for calculating the horizontal and vertical angular diameters of the shadow, and estimates values for the black holes at the centers of our Galaxy near Sgr A* and of the neighboring galaxy M87.

Einstein’s Shadow follows a team of elite scientists on their historic mission to take the first picture of a black hole, putting Einstein’s theory of relativity to its ultimate test and helping to answer our deepest questions about space, time, the origins of the universe, and the nature of reality Photographing a black hole sounds impossible, a contradiction in terms. But Shep Doeleman and a global coalition of scientists are on the cusp of doing just that. With exclusive access to the team, journalist Seth Fletcher spent five years following Shep and an extraordinary cast of characters as they assembled the Event Horizon Telescope, a worldwide network of radio telescopes created to study black holes. He witnessed the team’s struggles, setbacks, and breakthroughs, and, along the way, Fletcher explored the latest thinking on the most profound questions about black holes: Do they represent a limit to our ability to understand reality? Or will they reveal the clues that lead to the long-sought theory of everything? Fletcher transforms astrophysics into something exciting, accessible, and immediate, taking us on an incredible adventure to better understand the complexity of our galaxy, the boundaries of human perception and knowledge, and how the messy endeavor of science really works. Weaving a compelling narrative account of human ingenuity with excursions into cutting-edge science, Einstein’s Shadow is a tale of great minds on a mission to change the way we understand our universe—and our place in it.

"Black holes are one of the extraordinary phenomena in the universe whose existence was surmised not by observations, but by theory. The black hole is a prediction of Einstein's 1915-1916 gravitational theory, general relativity, which replaced Sir Isaac Newton's gravity theory, published in his famous treatise Principia in 1687. In 1784, Reverend John Michell, a fellow of Queens' College and Professor of Geology at Cambridge University, had already envisioned what we now call black holes. He asked what would happen if a star's gravity were so strong that its escape velocity - the speed at which a rocket, for example, would have to travel to leave the star - exceeded the speed of light? Michell realized that any light emanating from the star would have to fall back to its surface. He speculated that the escape velocity would exceed the speed of light for a very massive star, making the star invisible to an observer"--

Black holes entered the world of science fiction and films in the 1960s, and their popularity in our culture remains today. The buzz surrounding black holes was and is due, in large part, to their speculative nature. It is still difficult for the general public to determine fact versus fiction as it pertains to this terrifying idea: something big enough to swallow anything and everything in close proximity, with a gravitational force so strong that nothing, including light, can escape. In the fall of 2015, scientists at the Laser Interferometry Gravitational-Wave Observatory (LIGO) detected the first sounds from black holes, brought to earth by the gravitational waves that emitted from the merging of two black holes 1.4 billion light years away in space. This confirmed the existence of gravitational waves, which Albert Einstein predicted in 1916. In the spring of 2017, physicists and astronomers who were working on the Event Horizon Telescope (EHT) project captured the first image of a black hole. This was the supermassive black hole hosted by the galaxy M87 in the constellation Virgo, 53 million light years away, and the image shows the shadow the black hole casts upon the bright light surrounding it. In this book, John Moffat shares the history of black holes and presents the latest research into these mysterious celestial objects, including the astounding results from gravitational wave detection and the shadow of the black hole.

From the acclaimed author of Black Hole Blues and Other Songs from Outer Space—an authoritative and accessible guide to the most alluring and challenging phenomena of contemporary science. "[Levin will] take you on a safe black hole trip, an exciting travel story enjoyed from your chair’s event horizon.” —Boston Globe Through her writing, astrophysicist Janna Levin has focused on making the science she studies not just comprehensible but also, and perhaps more important, intriguing to the nonscientist. In this book, she helps us to understand and find delight in the black hole—perhaps the most opaque theoretical construct ever imagined by physicists—illustrated with original artwork by American painter and photographer Lia Halloran. Levin takes us on an evocative exploration of black holes, provoking us to imagine the visceral experience of a black hole encounter. She reveals the influence of black holes as they populate the universe, sculpt galaxies, and even infuse the whole expanse of reality that we inhabit. Lively, engaging, and utterly unique, Black Hole Survival Guide is not just informative—it is, as well, a wonderful read from first to last.

A NEW YORK TIMES EDITOR'S CHOICE Einstein’s Shadow follows a team of elite scientists on their historic mission to take the first picture of a black hole, putting Einstein’s theory of relativity to its ultimate test and helping to answer our deepest questions about space, time, the origins of the universe, and the nature of reality Photographing a black hole sounds impossible, a contradiction in terms. But Shep Doeleman and a global coalition of scientists are on the cusp of doing just that. With exclusive access to the team, journalist Seth Fletcher spent five years following Shep and an extraordinary cast of characters as they assembled the Event Horizon Telescope, a virtual radio observatory the size of the Earth. He witnessed their struggles, setbacks, and breakthroughs, and along the way, he explored the latest thinking on the most profound questions about black holes. Do they represent a limit to our ability to understand reality? Or will they reveal the clues that lead to the long-sought Theory of Everything? Fletcher transforms astrophysics into something exciting, accessible, and immediate, taking us on an incredible adventure to better understand the complexity of our galaxy, the boundaries of human perception and knowledge, and how the messy human endeavor of science really works. Weaving a compelling narrative account of human ingenuity with excursions into cutting-edge science, Einstein’s Shadow is a tale of great minds on a mission to change the way we understand our universe—and our place in it.

A sci-fi thrill ride—incredible action, inventive world-building, deadly humor, and more—for fans of movie classics such as Blade Runner and Mad Max! This is the companion to Invisible Sun and Black Hole Sun, which Suzanne Collins, the author of The Hunger Games, called "imaginative and action-packed." Characters return, new characters are introduced, and the action never stops. Readers embraced the first two books in acclaimed author David Macinnis Gill's trilogy about Durango, Mimi (his nano-implant with a biting wit), and Vienne (his second-in-command), calling the books non-put-downable, thrilling, funny, and totally satisfying. A surefire bet for fans of dystopian sci-fi, from The Hunger Games to Battlestar Galactica. Cinematic action, rapid-fire dialogue, a futuristic setting on a terraformed Mars, and tragic romance—Shadow on the Sun is an unstoppable adrenaline rush!

Proceedings of IAU Symposium No. 64, Warsaw, Poland, September 5-8, 1973