General Relativity

On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it to vary with regard to a second physical degree of freedom. At a quantum level, this view of change as relative variation leads to a fundamentally timeless formalism for quantum gravity. Here, we will show how one may avoid this acute ‘problem of time’. Under our view, (...) duration is still regarded as relative, but temporal succession is taken to be absolute. Following our approach, which is presented in more formal terms in, it is possible to conceive of a genuinely dynamical theory of quantum gravity within which time, in a substantive sense, remains. 1 Introduction1.1 The problem of time1.2 Our solution2 Understanding Symmetry2.1 Mechanics and representation2.2 Freedom by degrees2.3 Voluntary redundancy3 Understanding Time3.1 Change and order3.2 Quantization and succession4 Time and Gravitation4.1 The two faces of classical gravity4.2 Retaining succession in quantum gravity5 Discussion5.1 Related arguments5.2 Concluding remarks. (shrink)

According to the standard interpretation of Einstein’s field equations, gravity consists of mass-energy curving spacetime, and an additional physical force or entity—denoted by Λ (the ‘cosmological constant’)—is responsible for the Universe’s metric-expansion. Although General Relativity’s direct predictions have been systematically confirmed, the dominant cosmological model thought to follow from it—the ΛCDM (Lambda cold dark matter) model of the Universe’s history and composition—faces considerable challenges, including various observational anomalies and experimental failures to detect dark matter, dark energy, or inflation-field candidates. This (...) paper shows that Einstein’s Equivalence Principle entails two possible physical interpretations of General Relativity’s field equations. Although the field equations facially appear to support the standard interpretation—that gravity consists of mass-energy curving spacetime—the field equations can be equivalently understood as holding that gravitational effects instead result from mass-energy accelerating the metric-expansion of a second-order spacetime fabric superimposed upon an absolute, first-order Euclidean space, resulting in the observational appearance of spacetime curvature. This alternative interpretation of relativity is shown to be empirically equivalent to the standard interpretation of relativity, albeit with a changing value for Λ (which is similar to how Λ is understood in the conception of Λ as ‘quintessence’, but in this case takes Λ to be gravity). The reconceptualization is then shown to potentially resolve major observational anomalies for the ΛCDM model, including recent observations conflicting with ΛCDM predictions, as well as failures to directly detect dark matter, dark energy, and inflation field/particle candidates. (shrink)

In General Relativity, the terms ‘reference frame’ and ‘coordinate system’ must be distinguished. The former refers to physical systems that are dynamically coupled with the gravitational field, aside from possible approximations, while the latter refers to a set of mathematical variables that are representative artefacts. This necessary distinction is lost in pre-general relativistic physics, where we can choose as a reference frame a system of real physical objects that is not affected and cannot affect the physical system under consideration. Therefore, (...) we can make it coincide with a coordinate system without the need for approximations. We propose a a novel three-fold distinction between three types of reference frames, considered as material systems. In particular, we discern between Idealised Reference Frames, Dynamical Reference Frames and Real Reference Frames, depending on their increasing physical role in the total dynamics. Using a Bianchi I model in Minisuperspace, we give a cosmological example of the use of a gravitational Dynamical Reference Frame, namely a reference frame constructed with gravitational degrees of freedom in the standard case where the gravitational stress-energy tensor is not defined in the Einstein field equations. We also analyse the role of active and passive diffeomorphisms in changing a reference frame. (shrink)

This is the table of contents and first chapter of Physics Meets Philosophy at the Planck Scale (Cambridge University Press, 2001), edited by Craig Callender and Nick Huggett. The chapter discusses the question of why there should be a theory of quantum gravity. We tackle arguments that purport to show that the gravitational field *must* be quantized. We then introduce various programs in quantum gravity and discuss areas where quantum gravity and philosophy seem to have something to say to each (...) other. (shrink)

What constitutes a scientific discovery? What role do discoveries play in science, its dynamics and social practices? Must every discovery be attributed to an individual discoverer (or a small number of discoverers)? The paper explores these questions by first critically examining extant philosophical explications of scientific discovery—the models of scientific discovery, propounded by Kuhn, McArthur, Hudson, and Schindler. As a simple, natural and powerful alternative, we proffer the “change-driver model”: in a nutshell, it takes discoveries to be cognitive scientific results (...) that have epistemically advanced science. The model overcomes the shortcomings of its precursors, whilst preserving their insights. We demonstrate its intensional and extensional superiority, especially with respect to the link between scientific discoveries and the dynamics of science, as well as the award system of science. Both as an illustration, and as an application to a recent scientific and political controversy, we apply the considered models of discovery to one of the most momentous discoveries of science: the expansion of the universe. We oppose the 2018 proposal of the International Astronomers’ Union as too simplistic vis-`a-vis the historical complexity of the episode. The change- driver model yields a more nuanced and circumspect verdict: (i) The redshift-distance relation shouldn’t be named the “Hubble-Lemaître Law”, but “Slipher-Lundmark-Hubble-Humason Law”; (ii) Its interpretation in terms of an expanding universe, however, Lemaître ought to be given credit for; but (iii) The establishment of the expansion of the universe, as an evidentially sufficiently warranted result, is a communal achievement, emerging in the 1950s or 1960s. (shrink)

As is well known, Einstein was dissatisfied with the foundation of quantum theory and sought to find a basis for it that would have satisfied his need for a causal explanation. In this paper this abandoned idea is investigated. It is found that it is mathematically not dead at all. More in particular: a quantum mechanical U(1) gauge invariant Dirac equation can be derived from Einstein's gravity field equations. We ask ourselves what it means for physics, the history of physics (...) and for the actual discussion on foundations. (shrink)

The biochemistry of geotropism in plants and gravisensing in e.g. cyanobacteria or paramacia is still not well understood today [1]. Perhaps there are more ways than one for organisms to sense gravity. The two best known relatively old explanations for gravity sensing are sensing through the redistribution of cellular starch statoliths and sensing through redistribution of auxin. The starch containing statoliths in a gravity field produce pressure on the endoplasmic reticulum of the cell. This enables the cell to sense direction. (...) Alternatively, there is the redistribution of auxin under the action of gravity. This is known as the Cholodny-Went hypothesis [2], [3]. The latter redistribution coincides with a redistribution of electrical charge in the cell. With the present study the aim is to add a mathematical unified field explanation to gravisensing. (shrink)

Albert Einstein’s theory of General Relativity was once the leading theory in theoretical physics. Unfortunately the theory describes macroscopic reality without a clear link with the the microcosm in respect to the properties of spacetime. However the theory of General Relativity has proved to predict macroscopic phenomena in a very accurate way. Nowadays most theoretical physicists use the conceptual framework of quantum theory. So it is not surprisingly that the question about the “true nature” of spacetime becomes very intrigue.

We will make a new approach for an effect known as “Dark Energy” by an effect on gravitational field. In an accelerated rocket, the dimensions of space towards movement due to ‘Lorentz Contraction’ are on continuous reduction. Using the equivalence principle, we presume that in the gravitational field, the same thing would happen. In this implicates in ‘dark energy effect’. The calculi show that in a 7%-contraction for each billion years would explain our observation of galaxies in accelerated separation.

The standard model of cosmology is acclaimed in physics as accurate, robust, well-tested, our best scientific theory of the cosmos, but it has had serious anomalies for a while, including the Hubble tension, anomalous galaxies, and the completely unexplained nature of dark energy and dark matter. And lurking behind it all is the lack of a unified theory: General Relativity (GR) and quantum mechanics (QM) are inconsistent. Now startling new observations by the James Webb Space Telescope (JWST) in 2022 of (...) the early universe present the strongest challenge yet to the standard model, and whispers have started that this shows there is something wrong with the fundamental theory, General Relativity itself. This would be a crisis for cosmology. But haven’t they tested this theory already, and shown it is correct? How could it turn out wrong at this late stage? Here we compare the standard cosmology with an alternative fundamental theory, that has a strikingly different overall cosmological behavior: a simple cyclic expansion function. It is simple and deterministic. There are only two or three general parameters. The interesting result is that this alternative cosmology: (A) closely matches the expansion observed and modelled through the CDM standard model, now going back to red-shifts of 5-15; and (B) it also predicts unexpected early galaxy formation now being reported by the JWST. The point here is not to try to prove this alternative theory however, but rather show how it compares to the conventional cosmology. This show us clearly how weak the empirical evidence for the standard model really is against a counterfactual fundamental theory. Some results established in science are robust against theory change, but we find the standard cosmological model and the implications drawn from it are not robust at all. (shrink)

The Schwarzschild solution (Schwarzschild, 1915/16) to Einstein’s General Theory of Relativity (GTR) is accepted in theoretical physics as the unique solution to GTR for a central-mass system. In this paper I propose an alternative solution to GTR, and argue it is both logically consistent and empirically realistic as a theory of gravity. This solution is here called K-gravity. The introduction explains the basic concept. The central sections go through the technical detail, defining the basic solution for the geometric tensor, the (...) Christoffel symbols, Ricci tensor, Ricci scalar, Einstein tensor, stress-energy tensor and density-pressure for the system. The density is integrated, and some consistency properties are demonstrated. A notable feature is the disappearance of the event horizon singularity, i.e. there are no black holes. So far this is for a single central mass. A generalization of the solution for multiple masses is then proposed. This is required to support K-gravity as a viable general interpretation of gravity. Then the question of empirical tests is discussed. It is argued that current observational data is almost but not quite sufficient to verify or falsify K-gravity. The Pioneer spacecraft trajectory data is of particular interest, as this is capable of providing a test; but the data (which originally showed anomalies that match K-gravity) is now uncertain. A new and very practical experiment is proposed to settle the matter. This would provide a novel test of GTR, and a novel test of the cause of the Pioneer anomalies. In conclusion, K-gravity has extensive ramifications for gravitational physics and for the philosophy of GTR and space-time. (shrink)

Introduction to alternative ontology of mind and physics based on the multi-dimensional model of A Geometric Theory of the Universe (Holster).

The Simulation Hypothesis proposes that all of reality is in fact an artificial simulation, analogous to a computer simulation. Outlined here is a method for programming relativistic mass, space and time at the Planck level as applicable for use in Planck Universe-as-a-Simulation Hypothesis. For the virtual universe the model uses a 4-axis hyper-sphere that expands in incremental steps (the simulation clock-rate). Virtual particles that oscillate between an electric wave-state and a mass point-state are mapped within this hyper-sphere, the oscillation driven (...) by this expansion. Particles are assigned an N-S axis which determines the direction in which they are pulled along by the expansion, thus an independent particle motion may be dispensed with. Only in the mass point-state do particles have fixed hyper-sphere co-ordinates. The rate of expansion translates to the speed of light and so in terms of the hyper-sphere co-ordinates all particles (and objects) travel at the speed of light, time (as the clock-rate) and velocity (as the rate of expansion) are therefore constant, however photons, as the means of information exchange, are restricted to lateral movement across the hyper-sphere thus giving the appearance of a 3-D space. Lorentz formulas are used to translate between this 3-D space and the hyper-sphere co-ordinates, relativity resembling the mathematics of perspective. (shrink)

Defined are gravitational formulas in terms of Planck units and units of $\hbar c$. Mass is not assigned as a constant property but is instead treated as a discrete event defined by units of Planck mass with gravity as an interaction between these units, the gravitational orbit as the sum of these mass-mass interactions and the gravitational coupling constant as a measure of the frequency of these interactions and not the magnitude of the gravitational force itself. Each particle that is (...) in the mass-state (defined by a unit of Planck mass) per unit of Planck time is directly linked to every other particle also in the mass-state by a discrete unit of $m_P v^2 r = \hbar c$, the velocity of a gravitational orbit is summed from these individual $v^2$. As this approach presumes a digital time, it is suitable for use in programming Simulation Hypothesis models. As this link is responsible for the particle-particle interaction it is analogous to the graviton. Orbital angular momentum of the planetary orbits derives from the sum of the planet-sun particle-particle orbital angular momentum irrespective of the angular momentum of the sun itself and the rotational angular momentum of a planet includes particle-particle rotational angular momentum. (shrink)

The purpose of this note is to show how an 'AB-series' interpretation of time, given in a companion paper, leads, surprisingly, to AdS_5 geometry. This is not a theory of 2 time dimensions. Rather, it is a theory of 1 time dimension that has both A-series and B-series characteristics.

The purpose of this note is to show how an 'AB-series' interpretation of time leads, surprisingly, apparently, to AdS_5 geometry. This is not a theory of 2 time dimensions. Rather, it is a theory of 1 time dimension that has both A-series and B-series characteristics. To summarize the result, a spacetime in terms of (1) the earlier-to-later aspect of time, and (2) the (related) future-present-past aspect of time, and (3) 3-d space, it would seem, gives us the AdS_5 geometry.

This paper proposes an interpretation of time that is an 'A-theory' in that it incorporates both McTaggart's A-series and his B-series. The A-series characteristics are supposed to be 'ontologically private' analogous to qualia in the Inverted Spectrum thought experiment and is given a definition. It is proposed one may define a 'unit of becoming' that coordinatizes the future/present/past spectrum as well as allowing one to calculate the rates of becoming. We give a picture of this interpretation and discuss how it (...) relates to the Schrodinger's Cat paradox. (shrink)

This paper proposes an interpretation of time that is an 'A-theory' in that it incorporates both McTaggart's A-series and his B-series. The A-series characteristics are supposed to be 'ontologically private' analogous to qualia in the Inverted Spectrum thought experiment and is given a definition. The main idea is that the experimenter and the cat do not share the same A-series characteristics. So there is no single time at which the cat gets ascribed different states. It is proposed one may define (...) a 'unit of becoming' that coordinatizes the future/present/past spectrum as well as allowing one to calculate the rates of becoming. We give a picture of this interpretation and discuss how it relates to the Schrodinger's Cat 'paradox'. Also relativity is briefly considered. (shrink)

This paper proposes an interpretation of time that is an 'A-theory' in that it incorporates both McTaggart's A-series and his B-series. The A-series characteristics are supposed to be 'ontologically private' analogous to qualia in the problem of other minds and is given a definition. The main idea is that the experimenter and the cat do not share the same A-series characteristics, e.g the same 'now'. So there is no single time at which the cat gets ascribed different states. It is (...) proposed one may define a 'unit of becoming' that coordinatizes the future/present/past 'private' spectrum as well as allowing one to calculate the rates of becoming. Relativity is briefly considered. (shrink)

Les scientifiques espèrent qu'à l'avenir ils pourront tester des trous noirs en observant les effets causés par un fort champ gravitationnel à proximité, comme la lentille gravitationnelle. Il existe déjà des observations sur les lentilles gravitationnelles faibles, dans lesquelles les rayons lumineux sont déviés en quelques secondes seulement, mais jamais directement pour un trou noir. Il existe plusieurs candidats à cet effet, en orbite autour du Sagittaire A*. Plusieurs conjectures ad hoc ont été introduites pour mieux expliquer les observations de (...) candidats de trous noirs astronomiques identiques, mais avec des mécanismes de fonctionnement différents : gravastar, étoile noire (gravité semi-classique) , étoile à énergie noire, etc. DOI: 10.13140/RG.2.2.27478.06723. (shrink)

Au fil du temps, la théorie de la relativité générale a accumulé plusieurs anomalies, indiquant la nécessité de meilleures théories sur la gravité ou d'autres approches. Les hypothèses ad hoc introduites en relativité générale pour expliquer les singularités gravitationnelles basées sur les conditions énergétiques ne sont pas très efficaces. Des hypothèses plus détaillées sur le contenu du sujet sont nécessaires . De nombreux scientifiques et philosophes sont parvenus à la conclusion que les singularités doivent être associées à l'atteinte des limites (...) de la validité physique de la relativité générale et qu'une nouvelle théorie, la gravité quantique, doit être développée. DOI: 10.13140/RG.2.2.12877.26085. (shrink)

Gravity remains the most elusive field. Its relationship with the electromagnetic field is poorly understood. Relativity and quantum mechanics describe the aforementioned fields, respectively. Bosons and fermions are often credited with responsibility for the interactions of force and matter. It is shown here that fermions factually determine the gravitational structure of the universe, while bosons are responsible for the three established and described forces. Underlying the relationships of the gravitational and electromagnetic fields is a symmetrical probability distribution of fermions and (...) bosons. Werner Heisenberg's assertion that the Schr\'f6dinger wave function and Heisenberg matrices do not describe one thing is confirmed. It is asserted that the conscious observation of Schr\'f6dinger's wave function never causes its collapse, but invariably produces the classical space described by the Heisenberg picture. As a result, the Heisenberg picture can be explained and substantiated only in terms of conscious observation of the Schr\'f6dinger wave function. Schr\'f6dinger\'92s picture is defined as information space, while Heisenberg\'92s picture is defined as classical space. B-theory postulates that although the Schr\'f6dinger picture and the Heisenberg picture are mathematically connected, the former is eternal while the latter is discrete, existing only as the sequence of discrete conscious moments. Inferences related to information-based congruence between physical and mental phenomena have long been discussed in the literature. Moreover, John Wheeler suggested that information is fundamental to the physics of the universe. However, there is a great deal of uncertainty about how the physical and the mental complement each other. Bishop Berkeley and Ernst Mach, to name two who have addressed the subject, simply reject the concept of the material world altogether. Professor Hardy defined physical reality as 'dubious and elusive'. It is proposed in this paper that physical reality, or physical instantiation in the classical space as described by Heisenberg picture is one thing with the consciousness. (shrink)

It is standardly believed that the generally time-reversal symmetric fundamental laws of physics themselves cannot explain the apparent asymmetry of time. In particular, it is believed that CP violation is of no help. In this paper, I want to push back against a quick dismissal of CP violation as a potential source for the arrow of time and argue that it should be taken more seriously for conceptualising time in physics. I first recall that CP violation is a key feature (...) of our best physical theory which also has large-scale explanatory import regarding the matter-antimatter asymmetry of the universe. I then investigate how CP violation may help to explain the directionality of time. I argue that accounts à la Maudlin that posit an intrinsic fundamental direction of time are not convincing and instead propose to utilise recent results from work on the dynamical approach to relativity theory. (shrink)

Empirismul logic al filosofiei științei a apărut în cea mai mare parte ca urmare a celor două teorii ale relativității lui Einstein, favorizând convenționalismul à la Poincaré față de neo-kantianism și pozitivismul machian. Filosofia empirismului logic al științei în sine se consideră că a fost formată din învățăturile extrase din teoria relativității. Câteva dintre cele mai caracteristice doctrine ale acestei filosofii (interpretarea elementelor a priori în teoriile fizice ca niște convenții, tratarea rolului necesar al convențiilor în dezvoltarea conceptelor teoretice din (...) observare, insistența asupra limbajului observațional în definirea termenilor teoretici) au fost folosite de Einstein în modelarea celor două teorii ale relativității. DOI: 10.13140/RG.2.2.34146.89281. (shrink)

Les premières interprétations philosophiques de la théorie de la relativité générale sont très diverses, chacune essayant d'identifier Einstein comme un adepte de cette philosophie. Les partisans de Mach ont souligné la tentative d'Einstein de mettre en œuvre une « relativisation de l'inertie » dans la théorie générale, et son approche opérationnaliste de la simultanéité. Les kantiens et les néo-kantiens ont montré l'importance des « formes intellectuelles » synthétiques dans la théorie générale, en particulier le principe de covariance générale. Les empiristes (...) logiques ont mis l'accent sur la méthodologie de la théorie, les conventions pour exprimer le contenu empirique. DOI: 10.13140/RG.2.2.15367.42404 . (shrink)

Când densitatea corpului devine suficient de mare, relativitatea generală prezice formarea unei găuri negre. Stelele neutronice de circa 1,4 mase solare și găurile negre sunt starea finală pentru evoluția stelelor masive. De obicei o gaură neagră într-o galaxie a jucat un rol important în formarea acesteia și a structurilor cosmice aferente. Astfel de corpuri oferă un mecanism eficient pentru emisia de radiații electromagnetice și formarea de microquasari. Accreția poate duce la jeturi relativiste. Relativitatea generală permite modelarea acestor fenomene, confirmate prin (...) observații. DOI: 10.13140/RG.2.2.18088.93441. (shrink)

Over time, the general theory of relativity has accumulated several anomalies and discrepancies, indicating the need for a better theory about gravity or other approaches. The ad-hoc hypotheses introduced in general relativity to explain gravitational singularities based on energy conditions are not very efficient. More detailed assumptions on the content of the subject are needed. Many scientists and philosophers have come to the conclusion that singularities must be associated with reaching the limits of the physical validity of general relativity, and (...) a new theory of quantum gravity needs to be developed. DOI: 10.13140/RG.2.2.32579.55848. (shrink)

Les singularités de la relativité générale résultant de la résolution des équations d'Einstein ont été et font encore l'objet de nombreux débats scientifiques : existe-t-il des singularités dans l'espace-temps ou pas ? Big Bang a été une singularité initiale ? Si les singularités existent, quelle est leur ontologie ? La théorie générale de la relativité est-elle une théorie qui a montré ses limites dans ce cas ? Dans cet essai, je soutiens qu'il existe des singularités et que la théorie de (...) la relativité générale, comme toute autre théorie scientifique à l'heure actuelle, n'est pas valable pour les singularités. Toutefois, comme le pensent certains scientifiques, cela ne signifie pas pour autant qu’il doit être considéré comme obsolète. Après une brève présentation des aspects spécifiques de la théorie classique newtonienne et de la théorie de la relativité spéciale et une brève présentation de la théorie de la relativité générale, le chapitre Ontologie de la relativité générale présente les aspects ontologiques de la relativité générale. Le chapitre suivant, Singularités, est consacré à la présentation des singularités aboutissant à la relativité générale, aux aspects spécifiques des trous noirs et de l’horizon des événements, y compris le débat Big Bang en tant que singularité d’origine et aux arguments en faveur de l’existence de ces singularités. Dans l'Ontologie des singularités, je parle des possibilités d'encadrement ontologique des singularités en général et des trous noirs en particulier, de l'argument du trou mis en évidence par Einstein, et des arguments présentés par les scientifiques selon lesquels il n'y a pas de singularités et donc que la théorie générale de la relativité est dans l'impasse. Dans Conclusions, je décris et résume brièvement les arguments qui soutiennent mes vues ci-dessus. -/- TABLE: -/- Abstract Introduction - La théorie classique et la relativité restreinte - La relativité générale 1. Ontologie de la relativité générale 2. Singularités - 2.1 Trous noirs - - 2.1.1 Horizon des événements - 2.2 Big Bang - 2.3 Y a-t-il des singularités ? 3. L'ontologie des singularités - Ontologie des trous noirs - L'argument du trou - Il n'y a pas des singularités Conclusions Notes Bibliographie -/- Mots-clés : relativité générale, théorie de la relativité générale, Albert Einstein, singularités, trou noir, horizon des événements, Big Bang, cosmologie, gravité -/- DOI: 10.13140/RG.2.2.28102.01606 . (shrink)

Principiul esențial de coordonare în teoria generală a relativității este principiul echivalenței, incluzând o euristică negativă în conformitate cu metodologia programelor științifice de cercetare a lui Imre Lakatos. Argumentul ”nu este acela că toate cadrele de referință sunt echivalente, ci că coordonarea clasică a mișcării uniforme în linie dreaptă cu căile particulelor fără forță aplicată nu poate fi realizată fără nicio ambiguitate sau inconssistență.” Principiul echivalenței afirmă că descompunerea mișcării gravitaționale într-o mișcare uniformă și o accelerație gravitațională nu poate fi (...) unică, deoarece căderea liberă nu se distinge la nivel local de mișcarea uniformă. DOI: 10.13140/RG.2.2.26839.62884. (shrink)

Singularitățile la care se ajunge în relativitatea generală prin rezolvarea ecuațiilor lui Einstein au fost și încă mai sunt subiectul a numeroase dezbateri științifice: Există sau nu, singularități? Big Bang a fost o singularitate inițială? Dacă singularitățile există, care este ontologia acestora? Este teoria generală a relativității o teorie care și-a arătat limitele în acest caz? În acest eseu argumentez faptul că există singularități, iar teoria generală a relativității, ca de altfel oricare altă teorie științifică din prezent, nu este valabilă (...) în interiorul orizontului evenimentelor. Dar asta nu presupune, așa cum consideră unii oameni de știință, că ea trebuie considerată ca fiind perimată. După o scurtă prezentare a aspectelor specifice din teoria clasică newtoniană și teoria specială a relativității, și o scurtă prezentare a teoriei generale a relativității, în capitolul Ontologia relativității generale prezint aspectele ontologice specifice relativității generale. Următorul capitol, Singularități, este dedicat prezentării singularităților care rezultă în relativitatea generală, a aspectelor specifice ale găurilor negre și orizontul evenimentelor, inclusiv dezbaterea despre Big Bang ca singularitate inițială, și argumentele în favoarea existenței singularităților. În Ontologia singularităților vorbesc despre posibilitățile de încadrare ontologică a singularităților în general și a găurilor negre în special, despre argumentul găurii pus în evidență de Einstein, și argumentele prezentate de oamenii de știință că nu există singularități și deci că teoria generală a relativității este în impas. Închei cu Concluziile în care expun și reiau pe scurt argumentele care ămi susțin opiniile prezentate mai sus. Aceasta este o traducere din limba engleză a lucrării: Sfetcu, Nicolae, "The singularities as ontological limits of the general relativity". (shrink)

Albert Einstein proposed three tests of general relativity, later named the classic tests of general relativity, in 1916: the precession of the perihelion of Mercury's orbit, sun light deflection, and the gravitational redshift of the light. For gravitational testing, the indirect effects of gravity are always used, usually particles that are influenced by gravity. In the presence of gravity, the particles move along curved geodesic lines. The sources of gravity that cause the curvature of spacetime are material bodies, depending on (...) their mass. But in relativity the mass relates to the energy through the formula E = mc2, and the energy with the momentum, according to the special relativity. DOI: 10.13140/RG.2.2.25608.16648. (shrink)

Dicke and Schiff established a framework for testing general relativity, including through null experiments and using the physics of space exploration, electronics and condensed matter, such as the Pound-Rebka experiment and laser interferometry. The gravitational lens tests and the temporal delay of light are highlighted by parameter γ of the PPN formalism, equal to 1 for general relativity and with different values in other theories. The BepiColombo mission aims to test the general theory of relativity by measuring the gamma and (...) beta parameters of the PPN formalism. DOI: 10.13140/RG.2.2.25673.70240. (shrink)

Cu ajutorul formalismului PPN se confruntă teoriile gravitației cu rezultatele experimentelor din sistemul solar. Parametrul γ din acest formalism evidențiază deformarea luminii și întârzierea luminii. Prin calcule în conformitate cu PPN se obține deformarea luminii în raport cu liniile drepte locale, comparativ cu tije rigide; din cauza curburii spațiului în jurul Soarelui, determinată de parametrul γ, liniile locale drepte sunt îndoite în raport cu liniile drepte asimptotice departe de Soare. Dezvoltarea interferometriei radio de bază foarte lungi (VLBI) a îmbunătățit măsurarea (...) deformării luminii, permițând observații VLBI transcontinentale și intercontinentale ale quasarilor și radio galaxiilor pentru a monitoriza rotația Pământului. DOI: 10.13140/RG.2.2.32362.67520. (shrink)

Gravitația clasică newtoniană admite o descriere geometrică. Împreună cu relativitatea specială, aceasta permite o descriere euristică a teoriei relativității generale. Mișcarea inerțială din mecanica clasică este legată de geometria spațiului și timpului, practic de-a lungul unor geodezice în care liniile de univers sunt linii drepte în spațiu-timpul relativist. Conform relativității generale, forţa de gravitaţie este o manifestare a geometriei locale spaţiu-timp. Relativitatea generală este o teorie metrică a gravitației. La baza ei sunt ecuațiile lui Einstein, care descriu relația dintre geometria (...) unei varietăți patrudimensionale, pseudo-Riemanniene, reprezentând spațiu-timpul și energia-impulsul conținut în acel spațiu-timp. Gravitația corespunde schimbărilor în proprietățile spațiului și timpului, care, la rândul lor, modifică traseele obiectelor. DOI: 10.13140/RG.2.2.36460.41606. (shrink)

When the density of the body becomes large enough, general relativity predicts the formation of a black hole. The neutron stars of about 1.4 solar masses and the black holes are the final stage for the evolution of the massive stars. Usually a black hole in a galaxy has played an important role in its formation and related cosmic structures. Such bodies provide an efficient mechanism for the emission of electromagnetic radiation and the formation of microquasars. Accretion can lead to (...) relativistic jets. General relativity allows the modeling of these phenomena, confirmed by observations. DOI: 10.13140/RG.2.2.33569.15202 . (shrink)

Einstein déclare que les théories évoluent à travers des déclarations basées sur l'observation, sous la forme de lois empiriques, à partir desquelles des lois générales sont obtenues. L'intuition et la pensée déductive jouent un rôle important dans ce processus. Après la phase initiale, l'investigateur développe un système de pensée guidée par des données empiriques, construit logiquement à partir d'hypothèses fondamentales (axiomes). La « vérité » d'une théorie résulte de sa corrélation avec un grand nombre d'observations uniques. Pour les mêmes données (...) empiriques, plusieurs théories peuvent différer. DOI: 10.13140/RG.2.2.36545.79205. (shrink)

The singularities from the general relativity resulting by solving Einstein's equations were and still are the subject of many scientific debates: Are there singularities in spacetime, or not? Big Bang was an initial singularity? If singularities exist, what is their ontology? Is the general theory of relativity a theory that has shown its limits in this case?

Dans la vision classique, l'espace et le temps sont des conteneurs ; la matière est le contenu. La propriété distinctive de la matière est qu'elle transporte de l'énergie et des impulsions, préservée dans le temps, ce qui donne à ces impulsions un caractère ontologique fondamental. La relativité générale a généré diverses interprétations philosophiques anciennes. Ses adhérents ont mis en avant la « relativisation de l'inertie » et le concept de simultanéité, les kantiens et les néo-kantiens ont souligné l'approche de certaines (...) « formes intellectuelles » synthétiques (en particulier le principe de covariance générale), et les empiriques logiques ont souligné la signification philosophique méthodologique de la théorie. DOI: 10.13140/RG.2.2.11533.38886. (shrink)

Au milieu des années 1970, de nombreuses théories alternatives de la gravité ont été confirmées par des expériences au niveau du système solaire, mais pas au niveau cosmologique. En 1974, Joseph Taylor et Russell Hulse ont découvert le pulsar binaire , dont les impulsions extrêmement stables ont été surveillées par radiotélescope, permettant une mesure précise des paramètres astrophysiques. En 1978, le taux de changement de la période orbitale du système a été mesuré, ce qui a été confirmé par la relativité (...) générale mais pas par la plupart des théories alternatives. DOI: 10.13140/RG.2.2.30141.69606. (shrink)

La théorie de la relativité spéciale d'Einstein repose sur deux postulats fondamentaux : le postulat de la lumière (la vitesse de la lumière, dans le « cadre de repos », est indépendante de la vitesse de la source), et le principe de la relativité. Cette dernière a été explicitement adoptée par Einstein comme moyen de restreindre la forme des lois, quelle que soit leur structure détaillée. Ainsi, nous avons la différence entre une théorie « constructive » et une théorie « (...) principale ». DOI: 10.13140/RG.2.2.13383.32166 . (shrink)

Singularitățile gravitaționale în relativitatea generală sunt locații în spațiu-timp unde câmpul gravitațional devine infinit. Curburile invariabile scalare ale spațiu-timpului includ o măsură a densității materiei. Unii fizicieni și filosofi consideră că, deoarece densitatea materiei tinde spre infinit în singularitate, legile spațiu-timpului nu mai sunt valabile acolo. O singularitățile gravitațională aproape unanim acceptată în astrofizică și cosmologie, ca cea mai timpurie stare a universului, este Big Bang. Nici în acest caz legile cunoscute ale fizicii nu mai sunt valabile. DOI: 10.13140/RG.2.2.27271.75681.

The current cosmological models are built based on general relativity. The solutions of the specific equations, Friedmann-Lemaître-Robertson-Walker, allow to model the evolution of the universe starting from the Big Bang. Some of the parameters of the universe have been established by observations. Based on these, and other observational data, the models can be tested. Predictions include the initial abundance of chemical elements formed in a period of nucleosynthesis during the Big Bang period, the subsequent structure of the universe, cosmic background (...) radiation, and so on. DOI: 10.13140/RG.2.2.23725.64485. (shrink)

General relativity allows singularities, and we need to understand the ontology of singularities if we want to understand the nature of space and time in the present universe. Although some physicists believe that singularities indicate a failure of general relativity, others believe that singularities open a new horizon in cosmology, with real physical phenomena that can help deepen our understanding of the world. From the definitions of singularities, most known are the possibility that some spacetimes contain incomplete paths (most accepted), (...) the missing points, and the pathology of curvature. DOI: 10.13140/RG.2.2.31611.46888. (shrink)

Perioada dintre 1960 și 1980 a fost perioada de maturitate a relativității generale: s-au dezvoltat noi metode de testare de mare precizie care au inclus teste noi, precum precesiunea giroscopică, întârzierea luminii și "efectul Nordtvedt" în mișcarea lunară, utilizând inclusiv observații astrofizice și sateliții artificiali. Există diferențe mari de predicții între relativitatea generală și fizica clasică, precum dilatarea timpului gravitațional, lentila gravitațională, deplasarea spre roșu gravitațională a luminii, etc. Și există multe teorii relativiste ale gravitației, bifurcate sau independente, dar teoria (...) generală a relativității lui Einstein a confrmat toate predicțiile și este cea mai simplă dintre astfel de teorii. DOI: 10.13140/RG.2.2.20036.99205. (shrink)

The general theory of relativity was developed using as a nucleus a principle of symmetry: the principle of general covariance. Initially, Einstein saw the principle of general covariance as an extension of the principle of relativity in classical mechanics, and in SR. For Einstein, the principle of general covariance was a crucial postulate in the development of GR. The freedom of the GR diffeomorphism (the invariance of the form of the laws under transformations of the coordinates depending on the arbitrary (...) functions of space and time) is a "local" spacetime symmetry, as opposed to the "global" spacetime symmetries of the SR (which depend instead on the constant parameters ). DOI: 10.13140/RG.2.2.30854.32326. (shrink)

Les singularités gravitationnelles dans la relativité générale sont des emplacements dans l'espace-temps où le champ gravitationnel devient infini. Les courbes scalaires invariantes de l'espace-temps incluent une mesure de la densité de la matière. Certains physiciens et philosophes estiment que, du fait que la densité de la matière tend vers l'infini dans la singularité, les lois de l'espace-temps ne sont plus valables là-bas. Le Big Bang est une singularité gravitationnelle acceptée presque unanimement en astrophysique et en cosmologie, en tant que premier (...) état de l'univers. DOI: 10.13140/RG.2.2.32661.06886. (shrink)

In developing general relativity, Einstein was led by theoretical criteria of elegance and simplicity. His theory initially encountered "three classic tests": perihelion precession of Mercury's orbit, deflection of light by the Sun, and gravitational redshift of light. There are large differences in predictions between general relativity and classical physics, such as gravitational time dilation, gravitational lensing, gravitational redshift of light, and so on. And there are many relativistic theories of gravity, bifurcated or independent, but Einstein's general theory of relativity has (...) upheld all predictions and is the simplest of such theories. DOI: 10.13140/RG.2.2.13503.66723. (shrink)

For Einstein, simplicity is the main criterion in the theoretical choice when the experiments and observations do not give sufficiently clear indications . Univocity in the theoretical representation of nature should not be confused with a denial of the underdetermination thesis. The principle of univocality played a central role in Einstein's formulation of general relativity. According to Einstein, a constructive theory offers a constructive model for phenomena of interest. A principle theory consists of a set of well-substantiated individual empirical generalizations. (...) He states that this was his methodology in discovering the theory of relativity as the main theory, the other two principles being the principle of relativity and the principle of light. DOI: 10.13140/RG.2.2.17942.50242. (shrink)

Relativitatea generală a generat diverse interpretări filosofice timpurii. Adepții lui au evidențiat "relativizarea inerției" și conceptul de simultaneitate, kantienii și neo-kantienii au subliniat abordarea anumitor "forme intelectuale" sintetice (în special principiul covarianței generale, iar empiriștii logici au accentuat semnificația filozofică metodologică a teoriei. Reichenbach a abordat relativitatea generală prin prisma tezei "relativității geometriei", încercând o "axiomatizare constructivă" a teoriei relativității pe baza "problemelor elementare de fapt" (Elementaratbestande) cu privire la comportamentul observabil al razelor de lumină, a tijelor și a ceasurilor. (...) DOI: 10.13140/RG.2.2.27826.76486. (shrink)