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Einstein temperature damâ-ye Einstein (#) Fr.: température d'Einstein A characteristic parameter occurring in the → Einstein model of → specific heats. → Einstein; → temperature. |
Einstein tensor tânsor-e Einstein (#) Fr.: tenseur d'Einstein A mathematical entity describing the → curvature of → space-time in → Einstein's field equations, according to the theory of → general relativity. It is expressed by G_{μν} = R_{μν} - (1/2) g_{μν}R, where R_{μν} is the Ricci tensor, g_{μν} is the → metric tensor, and R the scalar curvature. This tensor is both symmetric and divergence free. Named after Albert Einstein (1879-1955); → tensor. |
Einstein time-scale marpel-e zamâni-ye Einstein Fr.: échelle de temps d'Einstein The time during which a → microlensing event occurs. It is given by the equation t_{E} = R_{E}/v, where R_{E} is the → Einstein radius, v is the magnitude of the relative transverse velocity between source and lens projected onto the lens plane. The characteristic time-scale of → microlensing events is about 25 days. → Einstein; → time-scale. |
Einstein's elevator bâlâbar-e Einstein Fr.: ascenseur d'Einstein A → thought experiment, involving an elevator, first conceived by Einstein to show the → principle of equivalence. According to this experiment, it is impossible for an observer situated inside a closed elevator to decide if the elevator is being pulled upward by a constant force or is subject to a gravitational field acting downward on a stationary elevator. Einstein used this experiment and the principle of equivalence to deduce the bending of light by the force of gravity. → einstein; elevator, from L. elevator, agent noun from p.p. stem of elevare "to lift up, raise," from → ex- "out" + levare "lighten, raise," from levis "light" in weight, → lever. Bâlâbar, → lift. |
Einstein's field equations hamugešhâ-ye meydân-e Einstein Fr.: équations de champ d'Einstein A system of ten non-linear → partial differential equations in the theory of → general relativity which relate the curvature of → space-time with the distribution of matter-energy. They have the form: G_{μν} = -κ T_{μν}, where G_{μν} is the → Einstein tensor (a function of the → metric tensor), κ is a coupling constant called the → Einstein gravitational constant, and T_{μν} is the → energy-momentum tensor. The field equations mean that the curvature of space-time is due to the distribution of mass-energy in space. A more general form of the field equations proposed by Einstein is: G_{μν} + Λg_{μν} = - κT_{μν}, where Λ is the → cosmological constant. Named after Albert Einstein (1879-1955); → field; → equation. |
Einstein's gravitational constant pâyâ-ye gerâneši-ye Einstein (#) Fr.: constante gravitationnelle d'Einstein The coupling constant appearing in → Einstein's field equations, expressed by: κ = 8πG/c^{4}, where G is the Newtonian → gravitational constant and c the → speed of light. → einstein; → gravitational; → constant. |
Einstein's theory of specific heat negare-ye garmâ-ye âbize-ye Einstein Fr.: théorie de la chaleur spécifique d'Einstein Same as → Einstein model. → Einstein; → theory; → specific heat. |
Einstein-de Sitter effect oskar-e Einstein-de Sitter Fr.: effet Einstein-de Sitter Same as → geodetic precession. |
Einstein-de Sitter Universe giti-ye Einstein-de Sitter Fr.: Univers Einstein-de Sitter The → Friedmann-Lemaitre model of → expanding Universe that only contains matter and in which space is → Euclidean (Ω_{M} > 0, Ω_{R} = 0, Ω_{Λ} = 0, k = 0). The Universe will expand at a decreasing rate for ever. → Einstein; de Sitter, after the Dutch mathematician and physicist Willem de Sitter (1872-1934) who worked out the model in 1917; → Universe. |
Einstein-Hilbert action žireš-e Einstein-Hilbert Fr.: action de Einstein-Hilbert In → general relativity, the → action
that yields → Einstein's field equations.
It is expressed by: → Einstein; → Hilbert space; → action. |
Einstein-Podolsky-Rosen paradox pârâdaxš-e Einstein-Podolsky-Rosen Fr.: paradoxe Einstein-Podolsky-Rosen → EPR paradox. A. Einstein, B. Podolsky, N. Rosen: "Can quantum-mechanical description of physical reality be considered complete?" Phys. Rev. 41, 777 (15 May 1935); → paradox. |
Einstein-Rosen bridge pol-e Einstein-Rosen Fr.: pont d'Einstein-Rosen A hypothetical structure that can join two distant regions of → space-time through a tunnel-like shortcut, as predicted by → general relativity. The Einstein-Rosen bridge is based on the → Schwarzschild solution of → Einstein's field equations. It is the simplest type of → wormholes. Albert Einstein & Nathan Rosen (1935, Phys.Rev. 48, 73); → bridge. |
Einsteinian relativity bâzânigi-ye Einsteini Fr.: relativité einsteinienne The laws of physics are the same in all → inertial reference frames and are invariant under the → Lorentz transformation. The → speed of light is a → physical constant, i.e. it is the same for all observers in uniform motion. Einsteinian relativity is prompted by the → Newton-Maxwell incompatibility. See also: → Galilean relativity, → Newtonian relativity. → Einstein; → relativity. |
einsteinium einsteinium (#) Fr.: einsteinium A radioactive metallic → transuranium element belonging to the → actinides; symbol Es. → Atomic number 99, → mass number of most stable → isotope 254 (→ half-life 270 days). Eleven isotopes are known. The element was first identified by A. Ghiorso and collaborators in the debris of first hydrogen bomb explosion in 1952. |
eject ešândan Fr.: éjecter To throw out material, for example by a massive star through stellar wind, or by a volcano in eruption. From L. ejectus, p.p. of eicere "to throw out," from → ex- "out" + -icere, comb. form of jacere "to throw." Ešândan, from Hamadâni ešândan "to throw out;" Pashto aestal, wištal "to throw, project;" Laki owštan "to throw, to shoot (with bow and arrow);" Lori šane "throwing," šane kerde "to throw;" Av. ah- "to throw," pres. ahya- "throws," asta- "thrown, shot," astar- "thrower, shooter;" cf. Khotanese ah- "to throw, shoot," Skt. as- "to throw, shoot," ásyati "throws," ásana- "throw, shot." |
ejecta ešânâk Fr.: éjecta Material, in solid, liquid, or gaseous form, thrown out by a body, especially as a result of → volcanic eruption, → meteoritic impact, or → supernova explosion. See also: → ejecta blanket, → supernova ejecta. Plural of L. ejectus, → eject. Ešânâk "that which is ejected," from šân present stem of šândan→ eject + suffix -âk. |
ejecta blanket patu-ye ešânâk Fr.: couverture d'éjecta Of an → impact crater, the ejecta that after the → impact event settles back to the Earth's surface. The ejecta blanket is thick near the → crater rim and thin outward from the crater. |
ejection ešâneš Fr.: éjection Act or instance of ejecting; the state of being ejected. Verbal noun of → eject. |
Ekman layer lâye-ye Ekman Fr.: couche d'Ekman A kind of viscous → boundary layer in a rotating fluid system. Such a layer forms over a flat bottom that exerts a frictional → stress against the flow, bringing the velocity gradually to zero within the layer above the bottom. An Ekman layer occurs also on the fluid surface whenever there is a horizontal frictional stress, for example along ocean surface, when waters are subject to wind stress. Named for Vagn Walfrid Ekman (1874-1954), Swedish oceanographer, who studied the phenomenon originally in his doctoral thesis (1902) and later developed it (1905, 1906); → layer. |
Ekman number adad-e Ekman Fr.: nombre d'Ekman A → dimensionless quantity that measures the strength of → viscous forces relative to the → Coriolis force in a rotating fluid. It is given by E_{k} = ν/(ΩH^{2}), where ν is the → kinematic viscosity of the fluid, Ω is the → angular velocity, and H is the depth scale of the motion. The Ekman number is usually used in describing geophysical phenomena in the oceans and atmosphere. Typical geophysical flows, as well as laboratory experiments, yield very small Ekman numbers. For example, in the ocean at mid-latitudes, motions with a viscosity of 10^{-2} m^{2}/s are characterized by an Ekman number of about 10^{-4}. → Ekman layer; → number. |
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