Relativitetsfysik

Tidsrummet mellem to begivenheder er afhængigt af, hvor hurtigt en observatør bevæger sig. Det er en af de besynderlige konsekvenser af Albert Einsteins specielle relativitetsteori fra 1905, der er en grundsten i den moderne fysik. I Speciel Relativitetsteori forklarer Ulrik Uggerhøj tid og rum. Han udleder bl.a. fundamentet for fænomener som tidsforlængelse, længdeforkortning og Lorentz-transformationerne, undersøger tyngdens indflydelse på tidens gang, sorte huller og gravitationsbølger og præsenterer løsninger på flere af teoriens tilsyneladende paradokser. Bogen indeholder forslag til læseforløb fra gymnasiale studieretningsprojekter til det avancerede universitetsniveau.

"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 to 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"--

Endeavors to explain Einstein's general theory of relativity, beginning with the equivalence principle and covering the necessary mathematics of Riemannian spaces and tensor calculus, offering readers a deeper understanding of the universe's real structure.

This graduate textbook covers the basic formalism of supergravity, as well as its modern applications, suitable for a focused first course. Assuming a working knowledge of quantum field theory, Part I gives the basic formalism, including on- and off-shell supergravity, the covariant formulation, superspace and coset formulations, coupling to matter, higher dimensions and extended supersymmetry. A wide range of modern applications are introduced in Part II, including string theoretical (T- and U-duality, AdS/CFT, susy and sugra on the worldsheet, superembeddings), gravitational (p-brane solutions and their susy, attractor mechanism, Witten's positive energy theorem) and phenomenological (inflation in supergravity, supergravity no-go theorems, string theory constructions at low energies, minimal supergravity and its susy-breaking). The broader emphasis on applications than competing texts gives Ph.D. students the tools they need to do research that uses supergravity and benefits researchers already working in areas related to supergravity.

By the star physicist and author of multiple #1 Sunday Times bestsellers, a major and definitive narrative work on black holes and how they can help us understand the universe. At the heart of our galaxy lies a monster so deadly it can bend space, throwing vast jets of radiation millions of light years out into the cosmos. Its kind were the very first inhabitants of the universe, the black holes.Today, across the universe, at the heart of every galaxy, and dotted throughout, mature black holes are creating chaos. And in a quiet part of the universe, the Swift satellite has picked up evidence of a gruesome death caused by one of these dark powers. High energy X-ray flares shooting out from deep within the Draco constellation are thought to be the dying cries of a white dwarf star being ripped apart by the intense tides of a supermassive black hole ? heating it to millions of degrees as it is shredded at the event horizon.They have the power to wipe out any of the universe's other inhabitants, but no one has ever seen a black hole itself die. But 1.8 billion light years away, the LIGO instruments have recently detected something that could be the closest a black hole gets to death. Gravitational waves given off as two enormous black holes merge together. And now scientists think that these gravitational waves could be evidence of two black holes connecting to form a wormhole ? a link through space and time. It seems outlandish, but today's physicists are daring to think the unthinkable ? that black holes could connect us to another universe.At their very heart, black holes are also where Einstein's Theory of General Relativity is stretched in almost unimaginable ways, revealing black holes as the key to our understanding of the fundamentals of our universe and perhaps all other universes.Join Professors Brian Cox and Jeff Forshaw in exploring our universe's most mysterious inhabitants, how they are formed, why they are essential components of every galaxy, including our own, and what secrets they still hold, waiting to be discovered.

A simple green combustion synthesis route was used to synthesize the CeO2 NPs using T. I. fruit extract as fuel. The structural, optical and catalytic properties of as-formed as well as calcined CeO2 NPs were studied in detail. From PXRD patterns confirmed the cubic phase of prepared CeO2 NPs. The effect of fuel on the crystallite size, energy band gap and PL properties were studied in detail. The prepared CeO2 NPs were agglomerated in nature with large number of surface voids were observed from the scanning electron microscope. The particle size was estimate from TEM results and found to be in the range of 5- 40 nm which was in good agreement with the PXRD results. From the chromaticity diagrams it was noticed that a blue color emission from the prepared samples. Further, modified electrodes by CeO2 NPs exhibits enhanced electrochemical sensing properties and hence can be used to fabricate the electrochemical sensing devices. The CeO2 NPs also showed good photocatalytic activity with respect to variation in pH and catalytic load. The above all results of CeO2 were fruitful in the fabrication of display devices, electrochemical sensing devices as well as a good Photocatalyst.

One of the effective instruments for examining atomic and molecular structures and widely used to examine a wide variety of chemicals is spectroscopy. The goal of the current book is to investigate several pharmacological substances utilizing theoretical calculation methods and spectroscopic approaches. It has also made it possible to use a commercial FT-IR spectrometer's extensive data handling capabilities. These techniques are used to measure the vibrational energy levels in a sample. Its applications are basic drug research and structural elucidation, formulation development and validation, quality control processes for incoming and outgoing materials, and packaging testing. The goal of obtaining an accurate understanding of the molecules' vibrational spectra is currently the focus of extensive research. The study of molecular dynamics has greatly been benefited from the density functional theory approach of examining molecular vibrations. This work has determined the vibrational frequencies and various properties of certain prominent natural particles using the Gaussian program, which is developed for performing DFT estimations.

Concise, undergraduate-level treatment covers time dilation, the twin paradox, momentum and energy, particles of zero mass, and many other elements of crucial theory. Replete with examples, ideal for self-study. 70 illustrations. 1965 edition.

This volume provides annotated translations of the primary sources, which were largely in German, leading up to Einstein's theory of general relativity, in which Einstein attempted to extend his theory of special relativity beyond space and time, to include matter and gravitational fields, by introducing gravity through his "equivalence principle" - the equivalence of gravity and acceleration. This resulted in Einstein rejecting the second postulate of his theory of special relativity - the postulate on the constancy of the speed of light - in the presence of a gravitational field. This review reveals that Einstein's theory of general relativity it is not a theory of gravity; it is a relativistic theory about the effects of gravitation, or more strictly, of a uniformly accelerated reference frame. There is nothing in any version of this theory that represents or explains or provides any connection to the weak attractive gravitational force between matter. In order to make calculations with his theory, Einstein had to import Newton's empirical law of gravitation. Consequently, the only evidence that Einstein could provide for his theory of general relativity was effectively Newtonian. Part I reviews Newton's laws of motion and of gravitation, his definitions of inertial and gravitational mass, and his equivalence principle, which provide the background to Einstein's theory. Part II provides a detailed analysis of the development of Einstein's theory of general relativity. Part III provides a postscript on subsequent developments, and the Conclusion. In the light of the continued failure of Einstein's efforts to overcome the main objections to his theory of special relativity - the Ehrenfest paradox, and its failure to explain the observed Doppler redshift and blueshift of light - or to provide any evidence for it, and in the absence of any supportive evidence for his theory of general relativity, both theories must be rejected until such objections are overcome and such evidence is provided.

In recent decades, twistor theory has grown into an irreplaceable tool for the study of scattering amplitudes in gauge theory and gravity. This book introduces the reader to cutting-edge advances in twistor theory and its applications to general relativity. The problem of graviton scattering in four dimensions is shown to be dual to dramatically simpler computations in a two-dimensional CFT known as a twistor sigma model. Twistor sigma models are the first step toward a holographic description of gravity in asymptotically flat space-times. They underpin the infinitely many asymptotic symmetries of flat space physics discovered in celestial holography, and extend them to exciting new arenas like curved space-times. They also yield intrinsically mathematical results in the field of hyperkähler manifolds. This volume will be of broad interest to students and researchers looking for an accessible entry point into twistor geometry, scattering amplitudes, and celestial holography. It will also provide an invaluable reference for specialists by bringing together results from a host of different disciplines.

Dimension Six offers a fresh perspective on the enigmatic relationship between the physical world and consciousness.

OSAU-3 Presents What, When, Where, Why, How and Who Is Us? an AWTbook(TM).

We know that matter exists in any one of the three states namely solid, liquid and gas. At the atomic level, these states of matter are distinguished from each other in terms of the nature of bonding among their atoms or molecules. Due to the unique nature of their atomic or molecular bonding, solids, liquids and gases possess characteristics macroscopic properties. In this book, we will study some of these properties of matter such as surface tension, viscosity, and elasticity. These properties have wide-ranging applications in engineering, industry, and even in our day-to-day lives such as twisting couples, cantilevers, the flow of liquid, the law of hydrostatic pressure, filter pump, surface tension, etc. This book also helps to create interest among the readers to know the magic of matter.

In this meticulously researched and beautifully crafted biography, you'll walk in the footsteps of a young einstein, whose insatiable curiosity led him from the unassuming town of ulm, germany, to the pinnacle of scientific achievement. Discover the genius behind the theory of relativity, the revolutionary equation e=mc², and his audacious challenges to the conventions of physics.But this biography goes beyond science. You'll uncover the human side of einstein, the advocate for peace and civil rights, and the man whose wisdom and wit continue to inspire. Inside you will read about...A genius shows up with a deformed headThe odd shaped head starts to readEinstein had a "miracle year"Einstein finds he has enemiesAlbert had his problems tooDid einstein have a 3rd son? You decideThe end is soon to comeIn his later years albert einstein was known as a gentle and lovable man who forgot his socks and rarely combed his hair. But he was much more than an absent-minded genius. He was a fierce individualist, who, as a teenager, renounced his german citizenship rather than serve in the army. As a rebel against every form of authority, an outspoken enemy of anti-semitism and fascism, and a socialist with an enduring commitment to social justice, you will learn in this book that even as einstein was setting newtonian physics on its ear, he considered his most important work to be about something very different: the bettering of humanity.

In the Collection ¿Quantum Gravity¿ the first article presents a new method for constructing quantum gravity, based on the equations of Einstein¿s general theory of relativity. It is shown that the natural space-time boundary is the Planck length. A new uncertainty relation between the gravitational radius of a particle and its position has been found. The basic equation of quantum gravity has been established. The inevitable nature of the three-dimensionality of space is shown. A hypothesis has been put forward about the nature of the singularities of black holes and the Metagalaxy. The second article establishes Bohr¿s general principle of complementarity, its extension to other areas of reality and its philosophical significance. The last article builds a visual model of special relativity and shows its role in scientific knowledge.

The purpose of this monograph is to present and systematize the theoretical and practical concepts of the physical principles of operation, design principles and methods for calculating and analyzing the parameters and modes of operation of individual functional elements (working bodies) of technological schemes (including elements of the main and auxiliary equipment) of turbines of thermal and nuclear power plants. The methodology of theoretical analysis of the thermodynamic cycles of the working substance in the flow path of the turbines of TPPs and NPPs implies an in-depth understanding of the laws of thermal-mechanical and heat exchange processes occurring on the elements of the blade apparatus (including nozzle and rotor blades) of the turbine stage. The methodology of this monograph is based on the basic laws and methods of technical thermodynamics, the theory of heat exchange processes and mass transfer processes. Methods of continuum mechanics hydrodynamics and gas.The manual is intended for students of the specialty "Heat power engineering" and also can be used by undergraduates of the specialty "Heat power engineering".

This study concludes that, quite apart from enormity of the consequences of the two postulates of Albert Einstein's theory of special relativity, taken together, including length contraction, time dilation, and the requirement to assume a point electron in the unsuccessful attempt to introduce special relativity into quantum electrodynamics, the evidence in support of Einstein's second postulate on the constancy of the speed of light is far outweighed by the evidence against it. For this reason, until more satisfactory evidence in support of Einstein's second postulate, a refutation of the Ehrenfest paradox, and an explanation for the observed Doppler red shift and blue shift consistent with Einstein's two postulates, is provided, under any normal measure of a theory in physics, Einstein's second postulate, and consequently his theory of special relativity, must be rejected. Part I provides annotated extracts and translations of the original papers leading up to the establishment of Einstein's theory of special relativity and Walter Ritz's competing emission theory of electromagnetic radiation. Part II examines the evidence in support of special relativity between 1905 and 2017. Part III addresses evidence against special relativity, reviews measurements of the speed of light, and provides the Conclusion.

This book focuses more on the lower dimension of the Cosmological model of the universe through the General Theory of Relativity. In this book, we have to drive and solve the different line elements with different equations of state in the (2+1)-Dimensional model. This book is more precise for lower-dimensional problems. We have solved cosmological modal in the modified theory of relativity as well as in another alternative theories of relativities.

One of the main unanswered question of modern Physics is "How does gravity behave at small scales?". The aim of this thesis is to illustrate in a comprehensive but accessible way how to look for deviations from Einstein's theory of General Relativity in this regime, looking at the simplest celestial bodies: static and spherically symmetric ones.With a conservative and bottom-up approach, at smaller scales the first corrections to the action of General Relativity are generally considered to be terms quadratic in the curvature tensors; while these modifications do not cure the inconsistency between gravity and quantum mechanics, the solutions of this theory are plausible candidates to be the first-order corrections of the classical ones.Even with such simple modifications, a striking picture emerges from the study of isolated objects: the unique Schwarzschild solution of General Relativity is only a rare bird in the set of solutions, with non-Schwarzschild black holes, wormholes and naked singularities appearing as possible substitutes.Tailored to graduate students and researchers entering this field, this thesis shows how to construct these new solutions from action principles, how to characterize their metric, how to study their physical properties, such as their stability or Thermodynamics, and how to look for phenomenological signatures.

This monograph delves into the subjects of braneworld cosmology and string theory phenomenology. Various supergravity inflationary models are discussed in the 5-dimensional braneworld scenario, and their predictions are compared to observations. Special emphasis is put on the gauge dependence of scalar-induced gravitational waves (SIGWs), focusing on the radiation domination (RD) and matter domination (MD) eras.In the second part, we present our modern understanding of gravity and the standard model of particle physics in the context of string theory phenomenology. Specifically, a supersymmetric Pati-Salam model with a wrapping number equal to 5 has been constructed from intersecting D6-branes on a Type IIA toroidal orientifold. Approximate string-scale gauge coupling unification is achieved. Remarkably, not only are the soft terms from supersymmetry breaking calculated, but we can also exactly accommodate exact fermion masses and mixings from three-point and four-point Yukawa interactions.