einstein’s general relativity
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2021 ◽  
Vol 34 (4) ◽  
pp. 464-469
Author(s):  
C. Y. Lo

Simulation shows that general relativity would lead to the existence of black holes if gravitation is always attractive. However, although we observed an invisible and extremely heavy object governs the orbits of stars at the center of our galaxy, we still cannot determine the existence of a black hole. Thus, one may ask whether black holes actually exist. Einstein’s general relativity has been established, because its prediction on the bending of light rays has been confirmed by observation. However, Einstein’s prediction on the increment of weight for a piece of metal as the temperature increases is proven incorrect by experiments, which actually show a reduction of weight. This leads to the necessary existence of repulsive gravitational force, which has been demonstrated by a charged capacitor hovering above the earth. Thus, Einstein, Newton, Galileo, and Maxwell all made the error of overlooking the repulsive gravitational charge-mass interaction. Thus, it is necessary to rejustify the existence of black holes, because gravity is not always attractive. Moreover, repulsive gravitational force makes it necessary to extend general relativity to a five-dimensional theory. Thus, to find out whether black holes exist, it is necessary to investigate the repulsive gravitation and a five-dimensional space.


2021 ◽  
Vol 30 (14) ◽  
Author(s):  
Hamsa Padmanabhan

The epoch of Cosmic Dawn, when the first stars and galaxies were born, is widely considered as the final frontier of observational cosmology today. Mapping the period between Cosmic Dawn and the present-day provides access to more than 90% of the baryonic (normal) matter in the universe, and unlocks several thousand times more Fourier modes of information than available in today’s cosmological surveys. We review the progress in modeling baryonic gas observations as tracers of the cosmological large-scale structure from Cosmic Dawn to the present day. We illustrate how the description of dark matter haloes can be extended to describe baryonic gas abundances and clustering. This innovative approach allows us to fully utilize our current knowledge of astrophysics to constrain cosmological parameters from future observations. Combined with the information content of multi-messenger probes, this will also elucidate the properties of the first supermassive black holes at Cosmic Dawn. We present a host of fascinating implications for constraining physics beyond the [Formula: see text]CDM model, including tests of the theories of inflation and the cosmological principle, the effects of nonstandard dark matter, and possible deviations from Einstein’s general relativity on the largest scales.


2021 ◽  
pp. 146-162
Author(s):  
A. J. Kox ◽  
H. F. Schatz

Chapter 8 describes, in terms that are accessible to a general audience, the development of quantum theory and general relativity in the first decades of the twentieth century and in particular Lorentz’s contributions to these theories. Among other topics, it discusses radiation theory, the work of Max Planck, the work of Einstein, and the work of Niels Bohr. These scientific developments eventually led to the end of classical physics. Special attention is paid to Lorentz’s acceptance of Einstein’s general relativity.


Author(s):  
Yun-Gang Li ◽  
Cheng-Shu Li

Newton's law of universal gravitation does not explain Mercury's orbit anomalous precession, and gravitational constant G values measured by different research teams do not coincide. This paper studied universal gravitation from a physical aesthetics and ideal fluid perspective, derived new formula for calculating the exact G value by using the speed of light in vacuum with formulas for error correction, and verified by experimental results of other scientists. This provides another explanation for Mercury's anomalous precession, which is completely different from Einstein's general relativity. Conclusion is that G equals 1/(16πc) and Mercury's anomalous precession equals 43"/cy should not be the evidence for prove Einstein's general relativity is correct. In addition, an experimental plan is proposed for the space agency to further verify who is right.


2020 ◽  
Vol 35 (36) ◽  
pp. 2044026
Author(s):  
E. V. Arbuzova

The cosmological history of the universe in the [Formula: see text] gravity is studied starting from the “very beginning” up to the present time. The primordial inflationary expansion of the universe is considered and it is shown that the gravitational particle production by the oscillating curvature, [Formula: see text], led to a consistent transition to the Friedmann cosmology, but the cosmological evolution in the early universe strongly differed from the standard one. It is shown that the effects of gravitational production of particles had a significant influence on the evolution of the universe.


2020 ◽  
Vol 3 (2) ◽  
pp. p162
Author(s):  
Niels Lynøe ◽  
Niklas Juth ◽  
Chris B Brook ◽  
Anders Eriksson

We argue that there are similarities between the Vulcan-must-exist-theory, derived from the Original Unrestricted Newtonian Gravitational (OUNG) theory, on the one hand, and on the other hand the infant-must-have-been-shaken-theory, derived from the Original Unrestricted Abusive Head Trauma (OUAHT) theory. Although the Vulcan-must–exist-theory was apparently supported by observations over a period of 50 years, after the introduction of Einstein’s general relativity theory in 1915 and its corroboration in 1919, the alleged planet was subsequently neither observed nor needed. In analogy with the Einstein/Vulcan reasoning, we suggest that the introduction of the non-shaken baby theory by Geddes et al. in 2001-2004 indicates that in cases where an infant displays no external signs of trauma, the infant-must-have-been-shaken-theory is no longer needed. Moreover we argue that the two new theories -Einstein’s and Geddes et al.’s- have relevant similarities in terms of the effect on the respective original, unrestricted theory. Just as acceptance of Einstein’s general relativity theory led to the abandonment of the Vulcan-must-exist-theory, it is reasonable to claim that the infant-must-have-been-shaken-theory should also be abandoned. We finally argue that while the consequences of abandoning the Vulcan-must-exist-theory were restricted to some scientific and astronomical issues, the infant-must-have-been-shaken-theory has not yet been abandoned because of the societal and legal consequences.


Author(s):  
Yun-Gang Li ◽  
Cheng-Shu Li

Newton's law of universal gravitation does not explain the Mercury's orbit anomalous precession, and the gravitational constant G values measured by different research teams do not coincide. This paper studied the two problems from a physical aesthetics and ideal fluid perspective, and derived a new formula for calculating the exact G value by using the speed of light in vacuum, including formulas for error correction, and verified by experimental results of other scientists. After being corrected, the G values measured by some famous surveyors approximately coincide with a specific value. The formulas also verified by the precession of Mercury's orbit and contribute an additional 35.94"/cy to the theoretical calculation value, the Mercury's anomalous precession, calculated by Le Verrier, is then reduced from 38"/cy to about 2"/cy. This provides another explanation for Mercury's anomalous precession which is completely different from that of Einstein's general relativity. Conclusion is that G equals 1/(16πc) when the masses are mass points and the Mercury's orbit anomalous precession equals 43"/cy should not be the evidence for prove Einstein's general relativity is correct. Further, this paper also presented an experimental plan for the space agency to verify who is right.


2020 ◽  
Vol 29 (13) ◽  
pp. 2030008 ◽  
Author(s):  
Tiberiu Harko ◽  
Francisco S. N. Lobo

Einstein’s General Relativity (GR) is possibly one of the greatest intellectual achievements ever conceived by the human mind. In fact, over the last century, GR has proven to be an extremely successful theory, with a well established experimental footing, at least for weak gravitational fields. Its predictions range from the existence of black holes and gravitational radiation (now confirmed) to the cosmological models. Indeed, a central theme in modern Cosmology is the perplexing fact that the Universe is undergoing an accelerating expansion, which represents a new imbalance in the governing gravitational equations. The cause of the late-time cosmic acceleration remains an open and tantalizing question, and has forced theorists and experimentalists to question whether GR is the correct relativistic theory of gravitation. This has spurred much research in modified theories of gravity, where extensions of the Hilbert–Einstein action describe the gravitational field, in particular, [Formula: see text] gravity, where [Formula: see text] is the curvature scalar. In this review, we perform a detailed theoretical and phenomenological analysis of specific modified theories of gravity and investigate their astrophysical and cosmological applications. We present essentially two largely explored extensions of [Formula: see text] gravity, namely: (i) the hybrid metric-Palatini theory; (ii) and modified gravity with curvature-matter couplings. Relative to the former, it has been established that both metric and Palatini versions of [Formula: see text] gravity possess interesting features but also manifest severe drawbacks. A hybrid combination, containing elements from both of these formalisms, turns out to be very successful in accounting for the observed phenomenology and avoids some drawbacks of the original approaches. Relative to the curvature-matter coupling theories, these offer interesting extensions of [Formula: see text] gravity, where the explicit nonminimal couplings between an arbitrary function of the scalar curvature [Formula: see text] and the Lagrangian density of matter, induces a nonvanishing covariant derivative of the energy-momentum tensor, which implies nongeodesic motion and consequently leads to the appearance of an extra force. We extensively explore both theories in a plethora of applications, namely, the weak-field limit, galactic and extragalactic dynamics, cosmology, stellar-type compact objects, irreversible matter creation processes and the quantum cosmology of a specific curvature-matter coupling theory.


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