TERMIUM Plus^®

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The geometric theory of gravitation developed by Albert Einstein, incorporating and extending the theory of special relativity to accelerated frames of reference and introducing the principle that gravity is a consequence of matter causing a curvature in spacetime.  3, record 1, English, - general%20theory%20of%20relativity

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The central idea of general relativity is that space and time are two aspects of spacetime. Spacetime is curved when there is gravity, matter, energy, and momentum.  4, record 1, English, - general%20theory%20of%20relativity

Record 1,  Textual support,  French

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Théorie géométrique de la gravitation formulée par Albert Einstein qui incorpore et applique la théorie de la relavité spéciale à des cadres de référence accélérés, de même qu'introduit la notion voulant que la gravité est une conséquence de la matière courbant l'espace-temps.  3, record 1, French, - th%C3%A9orie%20de%20la%20relativit%C3%A9%20g%C3%A9n%C3%A9rale

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Selon la relativité générale, l'attraction gravitationnelle que l'on observe entre les masses est provoquée par une déformation de l'espace et du temps par ces masses.  4, record 1, French, - th%C3%A9orie%20de%20la%20relativit%C3%A9%20g%C3%A9n%C3%A9rale

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Record 2,  Textual support,  English

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MOND is an alternative paradigm of dynamics, seeking to replace Newtonian dynamics and general relativity. It aims to account for the ubiquitous mass discrepancies in the Universe, without invoking the dark matter that is required if one adheres to standard dynamics.  3, record 2, English, - modified%20Newtonian%20dynamics%20theory

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MOND : acronyme anglais signifiant «modified Newtonian dynamics».  2, record 2, French, - th%C3%A9orie%20de%20la%20dynamique%20newtonienne%20modifi%C3%A9e

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The Big Crunch is one of the scenarios predicted by scientists in which the Universe may end. Just like many others, it is based on Einstein's theory of general relativity. That is, if the Big Bang describes how the Universe most possibly began, the Big Crunch describes how it will end as a consequence of that beginning.  3, record 3, English, - Big%20Crunch

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A theoretically deduced particle postulated as the quantum of the gravitational field, having a rest mass and charge of zero and a spin of 2.  2, record 4, English, - graviton

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Many physicists assume that gravitons exist, but few think that we will ever see them. These hypothetical elementary particles are a cornerstone of theories of quantum gravity, which seek to unify Albert Einstein's general theory of relativity with quantum mechanics. But they are notoriously hard — perhaps impossible — to observe in nature.  3, record 4, English, - graviton

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[A] theory that attempts to merge quantum mechanics with Albert Einstein's general theory of relativity.  2, record 5, English, - string%20theory

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String theory is one of the proposed methods for producing a theory of everything, a model that describes all known particles and forces and that would supersede the standard model of physics, which can explain everything except gravity.  3, record 5, English, - string%20theory

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Théorie qui cherche à unifier la mécanique quantique et la relativité générale.  2, record 5, French, - th%C3%A9orie%20des%20cordes

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On comprend qu'une théorie qui unifierait le modèle standard et la relativité générale, et qui expliquerait les quatre forces, constituerait dès lors une sorte de graal de la physique – on en parle même parfois comme d'une théorie du tout. Telle est précisément l'ambition de la théorie des cordes.  3, record 5, French, - th%C3%A9orie%20des%20cordes

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Physical theory incorporating both the principles of general relativity and quantum theory.  1, record 6, English, - quantum%20gravity

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Insofar as all extant physical theories rely on a classical (non-quantum) spacetime background, this presents not only extreme technical difficulties, but also profound methodological and ontological challenges for the philosopher and the physicist.  1, record 6, English, - quantum%20gravity

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Théorie de la gravitation quantique cherchant à unifier la relativité générale d'Einstein et la physique quantique dans un même cadre théorique.  1, record 6, French, - gravit%C3%A9%20quantique

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L’originalité de la gravité quantique consiste à prendre au sérieux la révo­lution conceptuelle inaugurée par la relativité générale quant à nos conceptions de l’espace et du temps.  2, record 6, French, - gravit%C3%A9%20quantique

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Record 7,  Textual support,  English

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There are several definitions in the literature of the notion of total angular momentum in general relativity. However, none of them can be said to capture the physical notion of intrinsic angular momentum of the sources in the presence of gravitational radiation. We present a definition of angular momentum for radiative spacetimes which does not suffer from any ambiguity of supertranslations.  1, record 7, English, - intrinsic%20angular%20momentum

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Les constituants du noyau, protons et neutrons, se meuvent à l'intérieur du noyau atomique et possèdent des caractéristiques électromagnétiques. Cela a pour conséquence l'existence de moments angulaires associés aux nucléons et au noyau pris dans son ensemble. Les différents types de moments angulaires sont les suivants : - le moment angulaire total [...] du noyau; - le moment angulaire intrinsèque du proton et du neutron.  1, record 7, French, - moment%20angulaire%20intrins%C3%A8que

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Momento angular de rotación de las partículas elementales.  1, record 7, Spanish, - momento%20angular%20intr%C3%ADnseco

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There are several definitions in the literature of the notion of total angular momentum in general relativity. However, none of them can be said to capture the physical notion of intrinsic angular momentum of the sources in the presence of gravitational radiation. We present a definition of angular momentum for radiative spacetimes which does not suffer from any ambiguity of supertranslations.  1, record 8, English, - total%20angular%20momentum

Record 8,  Textual support,  French

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Les constituants du noyau, protons et neutrons, se meuvent à l'intérieur du noyau atomique et possèdent des caractéristiques électromagnétiques. Cela a pour conséquence l'existence de moments angulaires associés aux nucléons et au noyau pris dans son ensemble. Les différents types de moments angulaires sont les suivants : - le moment angulaire total [...] du noyau; - le moment angulaire intrinsèque du proton et du neutron.  1, record 8, French, - moment%20angulaire%20total

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Record 9,  Textual support,  English

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The Centre national d’études spatiales(CNES) is developing an atomic clock of unequaled precision, which will be launched in 2003 aboard the International Space Station(ISS). The PHARAO clock(Cooled Atom In-Orbit Atomic Clock Project)... uses cooled cesium atoms in order to reach an accuracy and stability 10 to 100 times higher than any other high-performance existing calibrating clocks. The Cesium atoms are thrown on a free flight in a cavity enabling interaction with a radio-frequency field. They then transfer their intrinsic accuracy and stability qualities to the piezoelectric oscillator. The lack of gravity increases the time in which the atoms interact with the piezoelectric oscillator, which then increases the resolution and accuracy of the clock by a 10 factor. PHARAO will belong to ESA's ACES(Atomic Clock Ensemble in Space) payload within the frame of one of its ISS program. The ACES mission will be divided in two parts. The first one, which should last six months, will mostly focus on the PHARAO clock performance. The second part of the mission will last 12 months and will allow the international scientific community to use the clock for specific experiments(clocks’ synchronization, General Relativity tests, geodesy, etc.).  2, record 9, English, - ACES%20mission

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ACES mission: term officially approved by the International Space Station official approval Group (ISSOAG).  3, record 9, English, - ACES%20mission

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Les études sur les horloges à atomes froids et leurs implications en physique fondamentale et en métrologie temps/fréquences constituent des thèmes majeurs du Département «SYstèmes de Référence Temps Espace» (SYRTE) de l'Observatoire de Paris (actuellement laboratoire Systèmes de Références Spatio-Temporels) et en particulier du Laboratoire primaire du Temps et des Fréquences créé avec le Bureau National de métrologie. La mission ACES (Atomic Clock Ensemble in Space ) de l'Agence Spatiale Européenne apportera une contribution essentielle dans ces domaines. Parmi les objectifs scientifiques de la mission ACES, figurent la comparaison de fréquence de PHARAO, horloge spatiale à atomes froids, avec un ensemble d'horloges à atomes froids au sol, la détermination de l'exactitude de l'horloge spatiale et la recherche d'une éventuelle dérive de la constante de structure fine. Avec ses trois fontaines à atomes froids de césium et de rubidium, le laboratoire temps/fréquence jouera un rôle clé dans les comparaisons de fréquences.  2, record 9, French, - mission%20ACES

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mission ACES : terme uniformisé par le Groupe de travail de la terminologie de la Station spatiale internationale (GTTSSI).  3, record 9, French, - mission%20ACES

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J. A. Lipa, "An Unconventional Gyroscope for Testing Einstein's General Theory of Relativity. "  1, record 10, English, - unconventional%20gyroscope

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Normally, the classical gyroscope consists of a gyroscopic element (the rotor) suspended by a gimbal structure within a case.  3, record 10, English, - unconventional%20gyroscope

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Les gyroscopes classiques ont encore bien d'autres applications. [...] Gyroscopes non classiques. Gyroscope électrostatique [...] Gyromètres lasers [...] Gyroscope cryogénique [...] Gyroscope nucléaire.  1, record 10, French, - gyroscope%20non%20classique

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Le gyrolaser, contrairement au gyroscope mécanique, ne comporte aucune pièce mobile, et s'affranchit donc des erreurs dues aux frottements et aux défauts des liaisons mécaniques. Ainsi son facteur d'échelle k_g est inférieur à 10^-5 contre 10^-3 pour le gyroscope classique.  2, record 10, French, - gyroscope%20non%20classique

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Record 11,  Textual support,  English

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... the ring laser gyro concept is based on the principles of general relativity, which predict that the distance around a closed optical path in a rotating frame of reference depends on the direction the path is traversed. A beam of light traveling around the path in the direction of rotation will have to travel farther than one traveling in the opposite direction of rotation, and the pathlength difference can be used as a measure of angular rotation.  2, record 11, English, - optical%20path

Record 11,  Textual support,  French

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Application optique dans un domaine inattendu, la navigation inertielle, le gyrolaser est un nouveau gyromètre plus fiable que son prédécesseur mécanique, et particulièrement bien adapté aux conditions d'utilisation plus dures de l'avionique militaire et spatiale. [...] Principe. Effet Sagnac. L'interféromètre de Sagnac met en jeu, sur un trajet optique fermé, deux rayons lumineux se propageant en sens contraire. La rotation du bloc optique ainsi constitué introduit alors une différence de phase. Les calculs font appel à la relativité générale, et prouvent que le calcul classique est une bonne approximation. On montre ainsi que l'écart temporel DT est proportionnel à la vitesse de rotation W. La différence de chemin optique DL = c DT entre les deux rayons contrarotatifs [s'exprime dans une formule x].  3, record 11, French, - trajet%20optique

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Le gyrolaser est un oscillateur double constitué d'un laser à gaz. Sa cavité résonnante, triangulaire ou carrée, et dont les sommets sont matérialisés par des miroirs, contient du plasma (hélium - néon). Elle est parcourue par les ondes, de telle sorte que le chemin optique parcouru par les ondes soit multiple de leur longueur d'onde.  6, record 11, French, - trajet%20optique

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Trajet optique horaire, anti-horaire.  3, record 11, French, - trajet%20optique

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Supplément, défaut de trajet optique.  3, record 11, French, - trajet%20optique

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Record 12,  Textual support,  English

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... the ring laser gyro concept is based on the principles of general relativity, which predict that the distance around a closed optical path in a rotating frame of reference depends on the direction the path is traversed. A beam of light traveling around the path in the direction of rotation will have to travel farther than one traveling in the opposite direction of rotation, and the pathlength difference can be used as a measure of angular rotation.  1, record 12, English, - closed%20optical%20path

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See record "optical path."  2, record 12, English, - closed%20optical%20path

Record 12,  Textual support,  French

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L'interféromètre de Sagnac met en jeu, sur un trajet optique fermé, deux rayons lumineux se propageant en sens contraire. La rotation du bloc optique ainsi constitué introduit alors une différence de phase. Les calculs font appel à la relativité générale, et prouvent que le calcul classique est une bonne approximation.  1, record 12, French, - trajet%20optique%20ferm%C3%A9

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Voir la fiche «trajet optique».  2, record 12, French, - trajet%20optique%20ferm%C3%A9

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Record 13,  Textual support,  English

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Any theory that attempts to express gravitational theory and electromagnetic theory within a single unified framework; usually, an attempt to generalize Einstein's general theory of relativity from a theory of gravitation alone to a theory of gravitation and classical electromagnetism.  2, record 13, English, - unified%20field%20theory

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Record 14,  Textual support,  English

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a theory asserting that the laws of physics are identical in all inertial frames. It follows that the speed of light cannot be different in different frames, even if they are in relative motion. Thus the speed of light is a universal constant. Special relativity predicts a number of effects such as time dilation, length contraction and mass increases.  1, record 14, English, - special%20theory%20of%20relativity

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The topics are beyond the scope of this book but it is worth mentioning that Einstein's theory of special relativity deals with inertial frames, while his theory of general relativity deals with accelerated frames.  1, record 14, English, - special%20theory%20of%20relativity

Record 14,  Textual support,  French

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Une théorie selon laquelle le temps n'est pas indépendant du mouvement relatif des observateurs à cause de la vitesse finie de la lumière, la même pour tous les observateurs. La masse n'est pas invariante et augmente avec la vitesse du corps.  1, record 14, French, - th%C3%A9orie%20de%20la%20relativit%C3%A9%20restreinte

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