Gravity


Book Description




The Meaning of Quantum Gravity


Book Description

In discussing the question of whether General Relativity Theory really needs to be quantized, a simply negative answer cannot be accepted, of course. Such an answer is not satisfying because, first, Einstein's gravitational equations connect gravity and non-gravitational matter and because, second, it can be taken for granted that non-gravitational matter has an atomic or quantum structure such that its energy-momentum tensor standing on the right-hand side of Einstein's equations is formed out of quantum operators. These two facts make it impossible to read the left-hand side of Einstein's equations as an ordinary classical function. This does not necessarily mean, however, that we must draw the conclusion that General Relativity Theory, similar to electrodynamics, could or should be quantized in a rigorous manner and that this quantization has similar consequences to quantum electrodynamics. In other words, when for reasons of consistency quantization is tried, then one has to ask whether and where the quantization procedure has a physical meaning, i.e., whether there exist measurable effects of quantum gravity. IQ accordance with these questions, we are mainly dealing with the discus sion of the principles of quantized General Relativity Theory and with the estimation of quantum effects including the question of their measurability. This analysis proves that it is impossible to distinguish between classical and quantum General Relativity Theory for the extreme case of Planck's orders of magnitude. In other words, there does not exist a physically meaningful rigorous quantization conception for Einstein's theory.




The Biggest Ideas in the Universe


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INSTANT NEW YORK TIMES BESTSELLER “Most appealing... technical accuracy and lightness of tone... Impeccable.”—Wall Street Journal “A porthole into another world.”—Scientific American “Brings science dissemination to a new level.”—Science The most trusted explainer of the most mind-boggling concepts pulls back the veil of mystery that has too long cloaked the most valuable building blocks of modern science. Sean Carroll, with his genius for making complex notions entertaining, presents in his uniquely lucid voice the fundamental ideas informing the modern physics of reality. Physics offers deep insights into the workings of the universe but those insights come in the form of equations that often look like gobbledygook. Sean Carroll shows that they are really like meaningful poems that can help us fly over sierras to discover a miraculous multidimensional landscape alive with radiant giants, warped space-time, and bewilderingly powerful forces. High school calculus is itself a centuries-old marvel as worthy of our gaze as the Mona Lisa. And it may come as a surprise the extent to which all our most cutting-edge ideas about black holes are built on the math calculus enables. No one else could so smoothly guide readers toward grasping the very equation Einstein used to describe his theory of general relativity. In the tradition of the legendary Richard Feynman lectures presented sixty years ago, this book is an inspiring, dazzling introduction to a way of seeing that will resonate across cultural and generational boundaries for many years to come.




Sir Isaac Newton's Mathematical Principles of Natural Philosophy and His System of the World


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This title is part of UC Press's Voices Revived program, which commemorates University of California Press’s mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1934.




Gravity Is the Thing


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One of Real Simple’s Best Books of the Year “I loved this book. . . . Funny, heartbreaking and clever with a mystery at its heart.” —Jojo Moyes “With an eye as keen for human idiosyncrasies as Miranda July’s, and a sense of humor as bright and surprising as Maria Semple’s, this is a novel of pure velocity.” —Publishers Weekly (starred review) Twenty years ago, Abigail Sorenson’s brother Robert went missing one day before her sixteenth birthday, never to be seen again. That same year, she began receiving scattered chapters in the mail of a self-help manual, the Guidebook, whose anonymous author promised to make her life soar to heights beyond her wildest dreams. The Guidebook’s missives have remained a constant in Abi’s life—a befuddling yet oddly comforting voice through her family’s grief over her brother’s disappearance, a move across continents, the devastating dissolution of her marriage, and the new beginning as a single mother and café owner in Sydney. Now, two decades after receiving those first pages, Abi is invited to an all-expenses paid weekend retreat to learn “the truth” about the Guidebook. It’s an opportunity too intriguing to refuse. If Everything is Connected, then surely the twin mysteries of the Guidebook and a missing brother must be linked? What follows is completely the opposite of what Abi expected––but it will lead her on a journey of discovery that will change her life––and enchant readers. Gravity Is the Thing is a smart, unusual, wickedly funny novel about the search for happiness that will break your heart into a million pieces and put it back together, bigger and better than before.




Gravity's Shadow


Book Description

According to the theory of relativity, we are constantly bathed in gravitational radiation. When stars explode or collide, a portion of their mass becomes energy that disturbs the very fabric of the space-time continuum like ripples in a pond. But proving the existence of these waves has been difficult; the cosmic shudders are so weak that only the most sensitive instruments can be expected to observe them directly. Fifteen times during the last thirty years scientists have claimed to have detected gravitational waves, but so far none of those claims have survived the scrutiny of the scientific community. Gravity's Shadow chronicles the forty-year effort to detect gravitational waves, while exploring the meaning of scientific knowledge and the nature of expertise. Gravitational wave detection involves recording the collisions, explosions, and trembling of stars and black holes by evaluating the smallest changes ever measured. Because gravitational waves are so faint, their detection will come not in an exuberant moment of discovery but through a chain of inference; for forty years, scientists have debated whether there is anything to detect and whether it has yet been detected. Sociologist Harry Collins has been tracking the progress of this research since 1972, interviewing key scientists and delineating the social process of the science of gravitational waves. Engagingly written and authoritatively comprehensive, Gravity's Shadow explores the people, institutions, and government organizations involved in the detection of gravitational waves. This sociological history will prove essential not only to sociologists and historians of science but to scientists themselves.




Science in Our World


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A Question of Gravity and Light


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It is rare to find contemporary American poetry that speaks to readers with engaging directness, free of pretense or posturing. That is exactly the kind of poetry that Blas Falconer writes. In his first collection, Falconer presents 46 poems that are emotionally forthright and linguistically evocative but written without affectation or subterfuge. Although Falconer is formally trained and is aware of the structures and potential of both free verse and traditional poetic forms, he crafts exquisite, heartfelt poems that surprise us with their simple intensity. Whether writing about the mysteries of childhood or the pleasures of cruising for gay sex in a metropolitan airport, he surprises us with the delicacy of his touch, never obvious or heavy-handed. As a gay man who embraces his Puerto Rican heritage, Falconer stands at an edge of American society, and there is the tension of borders in his work: borders between peoples and nations as well as the less visible, more porous and deceptive borders between family members and lovers. There is not one point of view in these poems but many. It is the quality of their observational power that binds them together. Whether the setting is the hospital room of his dying grandfather or his own backyard teeming with garrulous tree frogs, Falconer transports us to the scene. It is easy for us to imagine what he sees. And we care, deeply, just as he does.




The Meaning of Quantum Gravity


Book Description

In discussing the question of whether General Relativity Theory really needs to be quantized, a simply negative answer cannot be accepted, of course. Such an answer is not satisfying because, first, Einstein's gravitational equations connect gravity and non-gravitational matter and because, second, it can be taken for granted that non-gravitational matter has an atomic or quantum structure such that its energy-momentum tensor standing on the right-hand side of Einstein's equations is formed out of quantum operators. These two facts make it impossible to read the left-hand side of Einstein's equations as an ordinary classical function. This does not necessarily mean, however, that we must draw the conclusion that General Relativity Theory, similar to electrodynamics, could or should be quantized in a rigorous manner and that this quantization has similar consequences to quantum electrodynamics. In other words, when for reasons of consistency quantization is tried, then one has to ask whether and where the quantization procedure has a physical meaning, i.e., whether there exist measurable effects of quantum gravity. IQ accordance with these questions, we are mainly dealing with the discus sion of the principles of quantized General Relativity Theory and with the estimation of quantum effects including the question of their measurability. This analysis proves that it is impossible to distinguish between classical and quantum General Relativity Theory for the extreme case of Planck's orders of magnitude. In other words, there does not exist a physically meaningful rigorous quantization conception for Einstein's theory.




On Gravity


Book Description

"Of the four fundamental forces of nature, gravity might be the least understood and yet the one with which we are most intimate. From the months each of us spent suspended in the womb anticipating birth to the moments when we wait for sleep to transport us to other realities, we are always aware of gravity. In On Gravity, physicist A. Zee combines profound depth with incisive accessibility to take us on an original and compelling tour of Einstein's general theory of relativity. Inspired by Einstein's audacious suggestion that spacetime could ripple, Zee begins with the stunning discovery of gravity waves. He goes on to explain how gravity can be understood in comparison to other classical field theories, presents the idea of curved spacetime and the action principle, and explores cutting-edge topics, including black holes and Hawking radiation. Zee travels as far as the theory reaches, leaving us with tantalizing hints of the utterly unknown, from the intransigence of quantum gravity to the mysteries of dark matter and energy. Concise and precise, and infused with Zee's signature warmth and freshness of style, On Gravity opens a unique pathway to comprehending relativity and gaining deep insight into gravity, spacetime, and the workings of the universe"--Publisher's website.