scholarly journals CONSTRAINING THE PREFERRED-FRAME α1, α2 PARAMETERS FROM SOLAR SYSTEM PLANETARY PRECESSIONS

2014 ◽  
Vol 23 (01) ◽  
pp. 1450006 ◽  
Author(s):  
L. IORIO
Keyword(s):  
Binary System ◽  
Solar System ◽  
Relative Motion ◽  
A Priori ◽  
The Other ◽  
Preferred Frame ◽  
General Relativistic ◽  
Ppn Parameters ◽  
Invariable Plane ◽  
Analytical Expressions

Analytical expressions for the orbital precessions affecting the relative motion of the components of a local binary system induced by Lorentz-violating Preferred Frame Effects (PFE) are explicitly computed in terms of the Parametrized Post-Newtonian (PPN) parameters α1, α2. Preliminary constraints on α1, α2 are inferred from the latest determinations of the observationally admitted ranges [Formula: see text] for any anomalous Solar System planetary perihelion precessions. Other bounds existing in the literature are critically reviewed, with particular emphasis on the constraint [Formula: see text] based on an interpretation of the current close alignment of the Sun's equator with the invariable plane of the Solar System in terms of the action of a α2-induced torque throughout the entire Solar System's existence. Taken individually, the supplementary precessions [Formula: see text] of Earth and Mercury, recently determined with the INPOP10a ephemerides without modeling PFE, yield α1 = (0.8±4) × 10-6 and α2 = (4±6) × 10-6, respectively. A linear combination of the supplementary perihelion precessions of all the inner planets of the Solar System, able to remove the a priori bias of unmodeled/mismodeled standard effects such as the general relativistic Lense–Thirring precessions and the classical rates due to the Sun's oblateness J2, allows to infer α1 = (-1 ± 6) × 10-6, α2 = (-0.9 ± 3.5) × 10-5. Such figures are obtained by assuming that the ranges of values for the anomalous perihelion precessions are entirely due to the unmodeled effects of α1 and α2. Our bounds should be improved in the near-mid future with the MESSENGER and, especially, BepiColombo spacecrafts. Nonetheless, it is worthwhile noticing that our constraints are close to those predicted for BepiColombo in two independent studies. In further dedicated planetary analyses, PFE may be explicitly modeled to estimate α1, α2 simultaneously with the other PPN parameters as well.

scholarly journals Astronomical Constraints on Some Long-Range Models of Modified Gravity

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Lorenzo Iorio
Keyword(s):  
Long Range ◽  
Modified Gravity ◽  
The Other ◽  
Newtonian Potential ◽  
Orbital Parameters ◽  
Curvature Invariants ◽  
General Relativistic ◽  
Braneworld Model ◽  
Analytical Expressions ◽  
Working Out

We use the corrections to the Newton-Einstein secular precessions of the longitudes of the perihelia of the inner planets, phenomenologically estimated E.V. Pitjeva by fitting almost one century of data with the EPM2004 ephemerides, to constrain some long-range models of modified gravity recently put forth to address the dark energy and dark matter problems. They are the four-dimensional ones obtained with the addition of inverse powers and logarithm of some curvature invariants, and the DGP multidimensional braneworld model. After working out the analytical expressions of the secular perihelion precessions induced by the corrections to the Newtonian potential of such models, we compare them to the estimated extra-rates of perihelia by taking their ratio for different pairs of planets instead of using one perihelion at a time for each planet separately, as done so far in literature. The curvature invariants-based models are ruled out, even by rescaling by a factor 10 the errors in the estimated planetary orbital parameters. Less neat is the situation for the DGP model. Only the general relativistic Lense-Thirring effect, not included, as the other exotic models considered here, by Pitjeva in the EPM force models, passes such a test.

scholarly journals Loops in the Sun’s orbit

2013 ◽  
Vol 40 (1) ◽  
pp. 127-134
Author(s):  
Milutin Marjanov
Keyword(s):  
Solar System ◽  
Relative Motion ◽  
Milky Way ◽  
Center Of Mass ◽  
The Other ◽  
The Sun ◽  
Solar System Bodies ◽  
Circular Outline

Besides translation, spin around its axis and rotation around center of the Milky Way, the Sun performs relative motion in the solar system Laplacian plane, also. This motion was anticipated by Newton himself, in his Principia. The form of the Sun?s orbit is substantially different from the other solar system bodies? orbits. Namely, the Sun moves along the path composed of the chain of large and small loops [1, 2, 6, 9]. This chain is situated within the circular outline with the diameter approximately twice as large as the Sun?s is. Under supposition that the solar system is stable, the Sun is going to move along it, in the same region, for eternity, never reitereiting the same path. It was also shown in this work that velocity and acceleration of the Sun?s center of mass are completely defined by the relative velocities and accelerations of the planets with respect to the Sun.

scholarly journals Another Name for Liberty: Revelation, ‘Objectivity,’ and Intellectual Freedom in Barth and Marion

Open Theology ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 430-450
Author(s):  
Kristóf Oltvai
Keyword(s):  
A Priori ◽  
The Other ◽  
Christian Theology ◽  
Intellectual Freedom ◽  
Specific Kind ◽  
Absolute Truth ◽  
Saturated Phenomenon ◽  
Other Hand ◽  
The Difference ◽  
The Relationship

Abstract Karl Barth’s and Jean-Luc Marion’s theories of revelation, though prominent and popular, are often criticized by both theologians and philosophers for effacing the human subject’s epistemic integrity. I argue here that, in fact, both Barth and Marion appeal to revelation in an attempt to respond to a tendency within philosophy to coerce thought. Philosophy, when it claims to be able to access a universal, absolute truth within history, degenerates into ideology. By making conceptually possible some ‚evental’ phenomena that always evade a priori epistemic conditions, Barth’s and Marion’s theories of revelation relativize all philosophical knowledge, rendering any ideological claim to absolute truth impossible. The difference between their two theories, then, lies in how they understand the relationship between philosophy and theology. For Barth, philosophy’s attempts to make itself absolute is a produce of sinful human vanity; its corrective is thus an authentic revealed theology, which Barth articulates in Christian, dogmatic terms. Marion, on the other hand, equipped with Heidegger’s critique of ontotheology, highlights one specific kind of philosophizing—metaphysics—as generative of ideology. To counter metaphysics, Marion draws heavily on Barth’s account of revelation but secularizes it, reinterpreting the ‚event’ as the saturated phenomenon. Revelation’s unpredictability is thus preserved within Marion’s philosophy, but is no longer restricted to the appearing of God. Both understandings of revelation achieve the same epistemological result, however. Reality can never be rendered transparent to thought; within history, all truth is provisional. A concept of revelation drawn originally from Christian theology thus, counterintuitively, is what secures philosophy’s right to challenge and critique the pre-given, a hermeneutic freedom I suggest is the meaning of sola scriptura.

Design of Midcourse Trajectory for Tactical Ballistic Missile Intercept on the Basis of Zero Effort Miss

2013 ◽  
Vol 397-400 ◽  
pp. 536-545
Author(s):  
Luo Gang Li ◽  
Wu Xing Jing ◽  
Chang Sheng Gao
Keyword(s):  
Relative Motion ◽  
Design Method ◽  
Ballistic Missile ◽  
Prediction Methods ◽  
Trajectory Design ◽  
Motion State ◽  
Simulating Calculation ◽  
Analytical Expressions ◽  
Maximal Principle ◽  
Computing Method

Since the maneuverability of the tactical ballistic missile, the midcourse trajectory of interception missile needs design online. Firstly, this paper reasonably simplifies the models and explores the analytical expressions of their relative motion state to obtain a kind of rapid and high-precision computing method of zero effort miss. Secondly, it applies constant thrust for the interception missile, burns out shut-down solid engine, reflects on the index requirement of overloaded interception missile, and designs midcourse trajectory of the interception missile with Pontryagin maximal principle, in accordance with the analytical expressions of zero effort miss. Finally, with the simulating calculation, the prediction methods of zero effort miss and trajectory design method provided by this paper are applied to a situation simulation which is close to the fact as much as possible so as to verify the applicability in the interception of tactical ballistic missile.

Hermann Weyl's Analysis of the “Problem of Space” and the Origin of Gauge Structures

2004 ◽  
Vol 17 (1-2) ◽  
pp. 165-197 ◽  
Author(s):  
Erhard Scholz
Keyword(s):  
General Relativity ◽  
Dirac Equation ◽  
A Priori ◽  
Group Extension ◽  
Central Idea ◽  
German Word ◽  
General Relativistic ◽  
Empirical Turn ◽  
Relativistic Framework ◽  
Internal Symmetries

Hermann Weyl (1885–1955) was one of the early contributors to the mathematics of general relativity. This article argues that in 1929, for the formulation of a general relativistic framework of the Dirac equation, he both abolished and preserved in modified form the conceptual perspective that he had developed earlier in his “analysis of the problem of space.” The ideas of infinitesimal congruence from the early 1920s were aufgehoben (in all senses of the German word) in the general relativistic framework for the Dirac equation. He preserved the central idea of gauge as a “purely infinitesimal” aspect of (internal) symmetries in a group extension schema. With respect to methodology, however, Weyl gave up his earlier preferences for relatively a-priori arguments and tried to incorporate as much empiricism as he could. This signified a clearly expressed empirical turn for him. Moreover, in this step he emphasized that the mathematical objects used for the representation of matter structures stood at the center of the construction, rather than interaction fields which, in the early 1920s, he had considered as more or less derivable from geometrico-philosophical considerations.

scholarly journals CAN GENERAL RELATIVISTIC DESCRIPTION OF GRAVITATION BE CONSIDERED COMPLETE?

1998 ◽  
Vol 13 (17) ◽  
pp. 1393-1400 ◽  
Author(s):  
D. V. AHLUWALIA
Keyword(s):  
Solar System ◽  
Gravitational Potential ◽  
Invariance Properties ◽  
Planetary Orbits ◽  
Galactic Cluster ◽  
General Relativistic ◽  
Relativistic Description ◽  
Flavor Oscillation ◽  
Weak Fields ◽  
Great Attractor

The local galactic cluster, the Great attractor, embeds us in a dimensionless gravitational potential of about -3×10-5. In the solar system, this potential is constant to about 1 part in 1011. Consequently, planetary orbits, which are determined by the gradient in the gravitational potential, remain unaffected. However, this is not so for the recently introduced flavor-oscillation clocks where the new redshift-inducing phases depend on the gravitational potential itself. On these grounds, and by studying the invariance properties of the gravitational phenomenon in the weak fields, we argue that there exists an element of incompleteness in the general relativistic description of gravitation. An incompleteness-establishing inequality is derived and an experiment is outlined to test the thesis presented.

scholarly journals Partial inverse problems for quadratic differential pencils on a graph with a loop

2020 ◽  
Vol 28 (3) ◽  
pp. 449-463 ◽  
Author(s):  
Natalia P. Bondarenko ◽  
Chung-Tsun Shieh
Keyword(s):  
Inverse Problems ◽  
A Priori ◽  
Spectral Characteristics ◽  
The Other ◽  
Boundary Edge ◽  
Partial Inverse ◽  
Quadratic Pencil ◽  
Sturm Liouville ◽  
Differential Pencils ◽  
Liouville Operators

AbstractIn this paper, partial inverse problems for the quadratic pencil of Sturm–Liouville operators on a graph with a loop are studied. These problems consist in recovering the pencil coefficients on one edge of the graph (a boundary edge or the loop) from spectral characteristics, while the coefficients on the other edges are known a priori. We obtain uniqueness theorems and constructive solutions for partial inverse problems.

THE INFLUENCE OF FAIR COMPETITION ON THE MANAGEMENT OF PUBLIC UNDERTAKINGS

2013 ◽  
Vol 8 (1) ◽  
pp. 42-54
Author(s):  
Camille Carbonnaux
Keyword(s):  
A Priori ◽  
Practical Importance ◽  
Competition Law ◽  
Legal Aspects ◽  
The Other ◽  
Common Features ◽  
Fair Competition ◽  
Management Perspective ◽  
The Common ◽  
European Competition Law

Since the 1990s, European judicial and normative institutions have paid particular attention to the competitive practices of public undertakings. Consequently, their regime is governed by a significant number of rules pursuing objectives appearing, a priori, contradictory. In fact, public undertakings may experience difficulties in their management. In this context, an approach of public competition law through the prism of fair competition can be very useful. Regarding the uniformity of its judgment, fair competition appears as an objective capable of coordinating rules and overcoming their contradictions. It thereby offers a global and coherent reading plan of all the legal translations of the European competitive order being of some practical importance. In illuminating the common features of the different legal aspects of competition, we can easily switch from one to the other. It therefore makes the European approach to competition more accessible and understandable. Furthermore, and most importantly, it leads to identifying legal opportunities and threats in a cross-disciplinary way. So, from a “Law & Management” perspective, it appears to be a precious tool for the management of public undertakings. Key words: European competition law, public undertakings, fair competition, “Management & law”.

scholarly journals Exploring language attitudes in ELF research: Contrasting approaches in conversation

2016 ◽  
Vol 3 (4) ◽  
pp. 74-109 ◽  
Author(s):  
Tomokazu Ishikawa ◽  
Sonia Morán Panero
Keyword(s):  
Present Article ◽  
Social Practice ◽  
Language Attitudes ◽  
A Priori ◽  
The Other ◽  
Research Projects ◽  
Doctoral Research ◽  
Two Sides ◽  
Ontological Position ◽  
Linguistic Phenomenon

AbstractWith reference to two recent doctoral research projects on ELF, the present article examines the characterisation of language attitudes as either stable or variable evaluative phenomena, and provides a detailed account of methodological practices that may be favoured from each ontological position. The durability of language attitudes is more specifically conceptualised as a stable (but not enduring) construct directed to a linguistic phenomenon in one thesis, and as variable and emergent forms of evaluative social practice around a language-related issue in the other. With these two different approaches in conversation, the authors consider the extent to which stability and variability of language attitudes may be two sides of the same coin, and question whether it is safe to assume a priori the inferability of stable language attitudes from the observation of evaluative practice. This article evidences the need for ELF researchers working in this area to contemplate what and how it is being researched in the name of language attitudes while having awareness of possible alternatives in any given study.

scholarly journals The influence of vortices upon the resitance experienced by solids moving through a liquid

1928 ◽  
Vol 119 (781) ◽  
pp. 146-156 ◽  
Keyword(s):  
Perfect Fluid ◽  
Relative Motion ◽  
Constant Velocity ◽  
Fluid Motion ◽  
Resultant Force ◽  
The Other ◽  
Two Dimensional ◽  
Perfect Fluids ◽  
Potential Problems ◽  
The Moment

(1) It is not so long ago that it was generally believed that the "classical" hydrodynamics, as dealing with perfect fluids, was, by reason of the very limitations implied in the term "perfect," incapable of explaining many of the observed facts of fluid motion. The paradox of d'Alembert, that a solid moving through a liquid with constant velocity experienced no resultant force, was in direct contradiction with the observed facts, and, among other things, made the lift on an aeroplane wing as difficult to explain as the drag. The work of Lanchester and Prandtl, however, showed that lift could be explained if there was "circulation" round the aerofoil. Of course, in a truly perfect fluid, this circulation could not be produced—it does need viscosity to originate it—but once produced, the lift follows from the theory appropriate to perfect fluids. It has thus been found possible to explain and calculate lift by means of the classical theory, viscosity only playing a significant part in the close neighbourhood ("grenzchicht") of the solid. It is proposed to show, in the present paper, how the presence of vortices in the fluid may cause a force to act on the solid, with a component in the line of motion, and so, at least partially, explain drag. It has long been realised that a body moving through a fluid sets up a train of eddies. The formation of these needs a supply of energy, ultimately dissipated by viscosity, which qualitatively explains the resistance experienced by the solid. It will be shown that the effect of these eddies is not confined to the moment of their birth, but that, so long as they exist, the resultant of the pressure on the solid does not vanish. This idea is not absolutely new; it appears in a recent paper by W. Müller. Müller uses some results due to M. Lagally, who calculates the resultant force on an immersed solid for a general fluid motion. The result, as far as it concerns vortices, contains their velocities relative to the solid. Despite this, the term — ½ ρq 2 only was used in the pressure equation, although the other term, ρ ∂Φ / ∂t , must exist on account of the motion. (There is, by Lagally's formulæ, no force without relative motion.) The analysis in the present paper was undertaken partly to supply this omission and partly to check the result of some work upon two-dimensional potential problems in general that it is hoped to publish shortly.

Sign in / Sign up

Export Citation Format

Share Document