scholarly journals New Time Scales: Removing Ambiguities

1995 ◽  
Vol 10 ◽  
pp. 255-255
Author(s):  
V.A. Brumberg
Keyword(s):  
Time Scales ◽  
Proper Time ◽  
Reference Systems ◽  
Physical Realization ◽  
Rotating Systems ◽  
The Earth ◽  
The Difference ◽  
Newtonian Type ◽  
Definition Of ◽  
Coordinate Gauge

The new (1991) IAU recommendations on reference systems and time scales are based completely on general relativity. But the metric forms determining the corresponding reference systems are specified in these recommendations not sufficiently definitive to take into account non-geodesic accelerations in the motion of the geocentre or topocentre, to distinguish between relativistic dynamically or kinematically non-rotating systems and to exclude a possible ambiguity in the time scales due to the relativistic coordinate gauge. There is a hidden ambiguity in the relativistic definition of the geocentre due to the difference bewteen Newtonian-type and Blanchet-Damour multipole moments used, respectively, in Brumberg-Kopejkin (Brumberg and Kopejkin, 1989; Kopejkin, 1991a; Brumberg et al., 1993; Klioner, 1993; Klioner and Voinov, 1993) and Damour-Soffel-Xu (1991-1994) approach to construct relativistic hierarchy of reference systems. In using TAI as physical realization of TT one should specify the constant LG(Fukushima, 1994) once for ever not introducing the relativistic ill-defined notion of the geoid (Kopejkin, 1991b). It might be reasonable not to separate this constant at all (as having no sense for moving clocks on the surface of the Earth or in the circumterrestrial space) and to use TAIM as physical realization of TCG itself relating TCG directly with the observer’s proper time avoiding the intermediate scale TT (Brumberg, 1992).

scholarly journals A non-rotating origin on the instantaneous equator

1988 ◽  
Vol 128 ◽  
pp. 33-38 ◽  
Author(s):  
N. Capitaine ◽  
B. Guinot
Keyword(s):  
Specific Rotation ◽  
Universal Time ◽  
Reference Systems ◽  
The Earth ◽  
Adopted Model ◽  
Fixed Reference ◽  
Rotation Of The Earth ◽  
Definition Of ◽  
Clear Description ◽  
Angle Of Rotation

In order to give an exact and clear description of the angle of rotation of the Earth, we propose to use, as the reference point in space, a “non-rotating origin” (Guinot 1979) such that its hour angle, reckoned from the origin of the longitudes (or “non-rotating origin” in the Earth), represents strictly the specific rotation of the Earth. The position of this origin on the instantaneous equator depends only on the trajectory of the pole of rotation. We show that the estimation of the deduced angle of rotation is not critically affected by the precision with which this trajectory is known. We give therefore the formulae to obtain the non-rotating origin, at any date t, from a chosen fixed reference, and we propose a definition of the Universal Time which will remain valid, even if the adopted model for the precession and the nutation is revised. We show that the use of the non-rotating origin also simplifies the transformation of coordinates between the terrestrial and celestial reference systems.

General Principles for the Realization of Reference Systems for Earth Dynamics

1975 ◽  
Vol 26 ◽  
pp. 261-267 ◽  
Author(s):  
G. Veis
Keyword(s):  
Reference System ◽  
Reference Systems ◽  
The Earth ◽  
Direct Measurements ◽  
Planets And Satellites ◽  
Definition Of ◽  
Earth Dynamics ◽  
Dynamic Phenomena ◽  
Selection Of ◽  
Better Than

A reference system is useful to express conveniently the location of a point and to study kinematic and dynamic phenomena. Although the definition of a reference system is theoretically very simple, its realization becomes very fifficult since it must be achieved by measurements reduced and expressed in this system.A referenoe system can be materialized by direct measurements of the coordinates or, more frequently, indirectly by measuring differential quantities and calculating the coordinates “de proche en proche.” The accuracy of the system definition cannot be better than the accuracy of the measurements themselves.For Earth dynamics we need a reference system related to the Earth, but since observations of other bodies such as galaxies, stars, planets, and satellites also may be required, the reference systems in which the positions of these bodies are expressed must also be related to the selected terrestrial system.To optimize the selection of a reference system one must consider both the phase of the operations for the establishment of the system and the phase of the utilization of the system, because the establishment of a reference system is not the final goal.

scholarly journals Definition and realization of the celestial intermediate reference system

2007 ◽  
Vol 3 (S248) ◽  
pp. 367-373 ◽  
Author(s):  
N. Capitaine
Keyword(s):  
Reference System ◽  
Reference Systems ◽  
The Earth ◽  
Fundamental Astronomy ◽  
International Terrestrial Reference System ◽  
Terrestrial Reference System ◽  
Rotation Of The Earth ◽  
Definition Of ◽  
Sidereal Rotation ◽  
Celestial Reference System

AbstractThe transformation between the International Terrestrial Reference System (ITRS) and the Geocentric Celestial Reference system (GCRS) is an essential part of the models to be used when dealing with Earth's rotation or when computing directions of celestial objects in various systems. The 2000 and 2006 IAU resolutions on reference systems have modified the way the Earth orientation is expressed and adopted high accuracy models for expressing the relevant quantities for the transformation from terrestrial to celestial systems. First, the IAU 2000 Resolutions have refined the definition of the astronomical reference systems and transformations between them and adopted the IAU 2000 precession-nutation. Then, the IAU 2006 Resolutions have adopted a new precession model that is consistent with dynamical theories and have addressed definition, terminology or orientation issues relative to reference systems and time scales that needed to be specified after the adoption of the IAU 2000 resolutions. These in particular provide a refined definition of the pole (the Celestial intermediate pole, CIP) and the origin (the Celestial intermediate origin, CIO) on the CIP equator as well as a rigorous definition of sidereal rotation of the Earth. These also allow an accurate realization of the celestial intermediate system linked to the CIP and the CIO that replaces the classical celestial system based on the true equator and equinox of date. This talk explains the changes resulting from the joint IAU 2000/2006 resolutions and reviews the consequences on the concepts, nomenclature, models and conventions in fundamental astronomy that are suitable for modern and future realizations of reference systems. Realization of the celestial intermediate reference system ensuring a micro-arc-second accuracy is detailed.

THE IAU RESOLUTION ON TIME SCALES AND REFERENCE SYSTEMS AND ITS IMPACT ON ASTROD

2002 ◽  
Vol 11 (07) ◽  
pp. 1011-1019 ◽  
Author(s):  
TIAN-YI HUANG ◽  
JIN-HE TAO
Keyword(s):  
Data Processing ◽  
Time Scales ◽  
Reference Systems ◽  
International Astronomical Union ◽  
Precision Data ◽  
Motion Equations ◽  
The Earth ◽  
International Astronomical ◽  
High Precision Data ◽  
Frame Work

Since 1976 the International Astronomical Union (IAU) has made a series of resolutions on the reference systems and time scales for high precision data processing in the frame- work of general relativity. This article reviews those resolutions that closely relate with the ASTROD project. We give our comments on how to meet the IAU resolutions in the future ASTROD data processing and what kind of works that need to be done further. For example, the self-gravitation terms should be included in the motion equation of the Earth, which is not included in the present DE ephemerides. And the effect of the Sun's figure on the motion of photons should be considered, which is partly neglected in the IAU metric. We also give the metric and the motion equations for both planets and photons in the parameterized post-Newtonian (PPN) formalism. A further improvement of the framework to the second post-Newtonian (2PN) precision would be necessary for the ASTROD project.

2. Definition of Land and Finders’ Titles

2020 ◽  
pp. 5-28
Author(s):  
Rosalind Malcolm
Keyword(s):  
Property Rights ◽  
Common Law ◽  
The Earth ◽  
Legal Implications ◽  
Questions And Answers ◽  
The Difference ◽  
Definition Of

The Concentrate Questions and Answers series offers the best preparation for tackling exam questions. Each book includes typical questions, bullet-pointed answer plans and suggested answers, author commentary, and illustrative diagrams and flowcharts. This chapter presents sample exam questions about the definition of land and finders’ titles. It considers the application of the Treasure Act 1996; the difference between fixtures and chattels and the legal implications of those differences; the definition of land; the meaning and application of the Latin maxims: cuius est solum eius est usque ad coelum et ad inferos (‘the owner of the land owns everything up to the sky and down to the centre of the earth’) and quicquid plantatur solo, solo cedit (‘whatever is attached to the land becomes part of the land’); the nature of property rights at common law; the relative nature of property rights; possession as font of title for finders; and title to registered land.

scholarly journals Construction of Relativistic Ephemerides and Applications

1997 ◽  
Vol 165 ◽  
pp. 233-238 ◽  
Author(s):  
X. Moisson
Keyword(s):  
Time Measurement ◽  
Relativity Theory ◽  
Reference Systems ◽  
General Relativity Theory ◽  
The Earth ◽  
Vlbi Observations ◽  
Analytical Integration ◽  
Definition Of ◽  
Near Future

AbstractThe present precision of VLBI observations for the Earth rotation, the accuracy of time measurement realised with modern atomic clocks, and the necessity to obtain precise definition of reference systems and links between them, imply that we compute in the near future more accurate ephemerides, based on general relativity theory (GRT), in accordance with the recent IAU resolutions (IAU, 1992). This paper is dedicated to the presentation of semi-analytical integration of the motion of bodies in the Solar system which completes the theories built at the Bureau des Longitudes by (Bretagnon and Francou, 1988), with some applications in the determination of coordinate time scales links.

The Origin of the Moon

1962 ◽  
Vol 14 ◽  
pp. 149-155 ◽  
Author(s):  
E. L. Ruskol
Keyword(s):  
Chemical Composition ◽  
Solar System ◽  
The Moon ◽  
The Earth ◽  
The Difference ◽  
Origin Of The Moon

The difference between average densities of the Moon and Earth was interpreted in the preceding report by Professor H. Urey as indicating a difference in their chemical composition. Therefore, Urey assumes the Moon's formation to have taken place far away from the Earth, under conditions differing substantially from the conditions of Earth's formation. In such a case, the Earth should have captured the Moon. As is admitted by Professor Urey himself, such a capture is a very improbable event. In addition, an assumption that the “lunar” dimensions were representative of protoplanetary bodies in the entire solar system encounters great difficulties.

The Distinction between [P] and [S]

2017 ◽  
Author(s):  
Galen Strawson
Keyword(s):  
Personal Identity ◽  
Radical Change ◽  
Legal Responsibility ◽  
The Difference ◽  
Definition Of ◽  
Over Time

This chapter examines the difference between John Locke's definition of a person [P], considered as a kind of thing, and his definition of a subject of experience of a certain sophisticated sort [S]. It first discusses the equation [P] = [S], where [S] is assumed to be a continuing thing that is able to survive radical change of substantial realization, as well as Locke's position about consciousness in relation to [P]'s identity or existence over time as [S]. It argues that Locke is not guilty of circularity because he is not proposing consciousness as the determinant of [S]'s identity over time, but only of [S]'s moral and legal responsibility over time. Finally, it suggests that the terms “Person” and “Personal identity” pull apart, in Locke's scheme of things, but in a perfectly coherent way.

L'anglicisme dans la langue française

2019 ◽  
Vol 3 ◽  
pp. 00013
Author(s):  
Danny Susanto
Keyword(s):  
English Language ◽  
Oil Industry ◽  
English Word ◽  
Public Institutions ◽  
Font Size ◽  
The World ◽  
French Speaking ◽  
The Difference ◽  
Definition Of ◽  
Bibliographic Study

<p class="Abstract">The purpose of this study is to analyze the phenomenon known as&nbsp;<span style="font-size: 1rem;">“anglicism”: a loan made to the English language by another language.&nbsp;</span><span style="font-size: 1rem;">Anglicism arose either from the adoption of an English word as a&nbsp;</span><span style="font-size: 1rem;">result of a translation defect despite the existence of an equivalent&nbsp;</span><span style="font-size: 1rem;">term in the language of the speaker, or from a wrong translation, as a&nbsp;</span><span style="font-size: 1rem;">word-by-word translation. Said phenomenon is very common&nbsp;</span><span style="font-size: 1rem;">nowadays and most languages of the world including making use of&nbsp;</span><span style="font-size: 1rem;">some linguistic concepts such as anglicism, neologism, syntax,&nbsp;</span><span style="font-size: 1rem;">morphology etc, this article addresses various aspects related to&nbsp;</span><span style="font-size: 1rem;">Anglicisms in French through a bibliographic study: the definition of&nbsp;</span><span style="font-size: 1rem;">Anglicism, the origin of Anglicisms in French and the current situation,&nbsp;</span><span style="font-size: 1rem;">the areas most affected by Anglicism, the different categories of&nbsp;</span><span style="font-size: 1rem;">Anglicism, the difference between French Anglicism in France and&nbsp;</span><span style="font-size: 1rem;">French-speaking Canada, the attitude of French-speaking society&nbsp;</span><span style="font-size: 1rem;">towards to the Anglicisms and their efforts to stop this phenomenon.&nbsp;</span><span style="font-size: 1rem;">The study shows that the areas affected are, among others, trade,&nbsp;</span><span style="font-size: 1rem;">travel, parliamentary and judicial institutions, sports, rail, industrial&nbsp;</span><span style="font-size: 1rem;">production and most recently film, industrial production, sport, oil industry, information technology,&nbsp;</span><span style="font-size: 1rem;">science and technology. Various initiatives have been implemented either by public institutions or by&nbsp;</span><span style="font-size: 1rem;">individuals who share concerns about the increasingly felt threat of the omnipresence of Anglicism in&nbsp;</span><span style="font-size: 1rem;">everyday life.</span></p>

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