Explore chapters and articles related to this topic
Gathering the Team
Published in Volker Knecht, AI for Physics, 2023
In the 20th century, the physical view of the world was turned upside down by two revolutionary theories supported by a wealth of experimental data. The first one is Albert Einstein's theory of relativity transforming our perception of space, time, and matter. Special relativity says the velocity of light in vacuum is the ultimate speed limit in nature and a fundamental constant connecting space and time to a four-dimensional spacetime. General relativity (often termed the most beautiful of all existing physical theories) declares gravity as curvature of spacetime. The second theory is quantum mechanics; it says energy (like light) is transmitted in quanta and microscopic objects have both particle and wave character, with often incredibly bizarre consequences.
Cosmic Microwave Background
Published in Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr, Fundamentals of Radio Astronomy, 2019
Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr
To understand the significance of this discovery, we need to appreciate the state of cosmology in the 1960's, and that requires starting in the early 20th century. Einstein, Albert Shortly after Einstein developed his general theory of relativity, in which gravity is attributed to curvature of space-time, he developed a model of the universe. Following the principles of general relativity, the space-time of the universe may be curved and the amount of curvature depends on the density of both mass and energy. Unaware at the time that the Universe was expanding, he found that the Universe could not be static if it contained mass or energy. Believing that the Universe was ever present and unchanging, Einstein inserted another parameter, which he called the cosmological constant Cosmological constant (Λ) and wrote as Λ, which counteracted gravity. By setting the value of the cosmological constant to the right value its effect could balance the curvature caused by the gravity due to mass, thereby yielding a static model of the Universe. Adding a cosmological constant is a simple modification to general relativity and affects physics on only the largest length scales and so did not conflict with measurements on the scales of galaxies and smaller. Einstein, Albert
Waves
Published in Daniel H. Nichols, Physics for Technology, 2019
Gravitational waves are ripples in space-time that travel at the speed of light caused by some violent and energetic event such as the merger of two black holes. Albert Einstein predicted such waves in 1916, in his theory of gravity, General Relativity. In 2015, approximately 100 years after Einstein’s prediction, these waves were first detected. The source of this detection turned out to be two black holes spiraling into one another. General Relativity predicts that when a mass is accelerated it will produce waves on the space surrounding it, think of ripples on a pond when a rock is tossed in. These waves are extremely weak and require extremely large accelerated masses, and a very sensitive instrument to measure them. This first detection of gravitational waves took place on twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana and Hanford, Washington, USA (Figure 15.43). The signals measured in these detectors agree with the prediction of the merger of two black holes about 29 and 36 times the mass of the sun 1.3 billion years ago; it took 1.3 billion years traveling at the speed of light to reach us.
Nonlinear streaming instability in viscoelastic quantum dusty plasmas
Published in Waves in Random and Complex Media, 2023
Smriti Roy, Tanushree Bezbaruah, Pralay Kumar Karmakar
It is optimistically believed that the proposed semi-analytic study should be extensively useful to explore varied nonlinear wave spectra and instability saturation mechanisms in plasma media. The nonlinear excitation of the TSI modal structurization is triggered by an initial equilibrium bulk (seed) flow causing a non-equilibrium collective structural pattern formation later amid the long-range gravito-electrostatic interplay. The obtained results seem to be useful to perceive the flow-induced phenomena in different laboratory experiments on laser-produced plasmas [32]. The inclusion of the EiBI gravity could yield interesting results with general relativity corrections in the futuristic relativistic perspective [38]. Finally, one could conclude herein that this seed flow-based multi-fluidic instability analysis could illuminate the basic physics behind mysterious collective non-thermal (anti-equilibrium) behaviors of large-scale correlated plasmas, particularly in different degenerate plasma configurations of more realistic investigative applicability, regardless of spatiotemporal scales.
Metric inertia for eddy densities of nonlocal matter-space
Published in Journal of Turbulence, 2021
Metric functions were introduced to modify the positive 4-interval and the positive kinetic energy of Special Relativity. Therefore, General Relativity introduced metric changes of kinetic energy, but not a new kind of energy in metric terms. The apparent phenomenon of mutual gravitation is the observable consequence of nonlocal eddy organisations, where negative (non-kinetic) energy cannot be the independent notion. The same is true for Coulomb ‘forces-accelerations’, which are merely adaptive consequences of nonlocal organisations. The fictional potentials of Newton and Coulomb (and non-Euclidean corrections to Euclidean 3-geometry of kinetic energies due to non-existing gravitational ‘forces’) have never been confirmed by the quantum measurements of the mechanical fluxoid using SQUIDs. Again, the local existence of adaptive self-accelerations in the monistic theory of metric inertia for eddy densities with correlated stresses does not mean the existence of gravitational energies and relevant forces. The fictional interaction force in non-existing Newtonian gravity do not change the total energy content of moving probe bodies. Local metric pushes or pressure of the ‘superpenetrating matter-liquid’ of Lomonosov is the reason for any local accelerations, while a non-existing distant force-fiction cannot be screened in nonlocal reality.
Geometric theory of topological defects: methodological developments and new trends
Published in Liquid Crystals Reviews, 2021
Sébastien Fumeron, Bertrand Berche, Fernando Moraes
A major contemporary challenge in physics is to find an extension of General Relativity able to describe gravity at all energy scales, in particular at the very beginning of the universe. This is the mission devoted to quantum gravity theories, which have the daunting task of reconciling Einstein's general relativity and quantum field theory. Despite promising attempts, including superstring theories, M-theory or quantum loop gravity, no proposal is entirely satisfactory up to now, and even so, the energy scales required to test these theories are far beyond our current scientific capabilities. A way out of this gridlock is to rely on simpler models that capture the essential features of quantum gravity but remain connected to low-energy-physics systems, i.e. analog gravity. The rare pearl was first introduced in a seminal paper by Deser, Jackiw and 't Hooft [141]: 2 + 1 gravity with point-particle sources.