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absolute acceleration šetâb-e avast Fr.: accélération absolue For a body that moves with respect to a rotating → reference frame, the vector sum of the observed acceleration, the → Coriolis acceleration, and the → centrifugal acceleration. See also the → Coriolis theorem. → absolute; → acceleration. |
absolute temperature damâ-ye avast Fr.: température absolue Also called → thermodynamic temperature, the value of a → temperature in the → Kelvin scale. It is is equal to the temperature on the → Celsius scale -273.15 °C. → absolute; → temperature. |
accelerate šetâbidan (#), šetâftan (#); šetâbândan (#) Fr.: accélérer (v.tr.) To increase the velocity of a body; to cause to undergo acceleration. Verbal form of → acceleration. |
accelerated motion jonbeš-e šetâbdâr (#) Fr.: mouvement accéléré The motion of an object subject to → acceleration. Opposite to → uniform motion. Accelerated, from → accelerate; → motion. Jonbeš, → motion; šetâbdâr "accelerated," from šetâb→ accelerate + dâr "having, possessor" (from dâštan "to have, to possess," Mid.Pers. dâštan, O.Pers./Av. root dar- "to hold, keep back, maitain, keep in mind;" cf. Skt. dhr-, dharma- "law;" Gk. thronos "elevated seat, throne;" L. firmus "firm, stable;" Lith. daryti "to make;" PIE *dher- "to hold, support"). |
accelerating šetâbandé (#) Fr.: en accélération Moving or proceeding with → acceleration; e.g. → accelerating system; → accelerating Universe. Verbal adj. from → accelerate. |
accelerating expansion of the Universe gostareš-e šetâbande-ye giti Fr.: expansion accélérée de l'Univers → accelerating; → expansion; → Universe. |
accelerating system râžmân-e šetâbandé Fr.: système en accélération A material system that is subject to a constant force in each and every one of its instantaneous points of trajectory. → accelerating; → system. |
accelerating Universe giti-ye šetâbandé (#) Fr.: univers en accélération The deduction based on the observation that the most distant → Type Ia supernovae are fainter than that expected from their → redshifts in a matter-only dominated expanding Universe. The faintness is attributed to larger distances resulting from an accelerating Universe driven by presence of a new component with strongly negative pressure. This component that makes the Universe accelerate is named → dark energy. The deceleration or acceleration of an expanding Universe, given by the general relativistic equation, is: R^{..}/R = -(4/3)πGρ(1 + 3w), where R is the linear → cosmic scale factor of the expanding Universe, G the → gravitational constant, ρ the mean density of the Universe, and w the → equation of state parameter representing dark energy. The expansion accelerates whenever w is more negative than -1/3. The Nobel Prize in Physics 2011 was awarded to the initiators of this concept, Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess, for their discovery of the accelerating expansion of the Universe through observations of distant supernovae. See also the original paper: Perlmutter et al. 1999, ApJ 517, 565. → accelerating; → universe. |
acceleration šetâb (#) Fr.: accélération The rate at which the velocity of an object changes with time. Acceleration, from accelerate, from L. accelerare "quicken," from → ad- "to" + celerare "hasten," from celer "swift" (cf. Skt. car, carati "to move, go, drive," Gk. keles "fast horse, horse race," Av. kar- "to walk, move, go around," Mod.Pers. cal, calidan "to move, to go, to walk" (jald? "quick, active, brisk"), Gilaki/Hamadâni jal "quick, fast,"Lori žil "motion, impulse"); PIE *kel- "to drive, set in swift motion." Šetâb "quickness, haste, speed," Mid.Pers. ôštâp "hurry, haste," ôštâftan "to hurry, hasten," from *abi.stap-, from abi- " to; in addition to; against" + *stap- "to oppress," Arm. (loanword) štap "haste, trouble." |
acceleration of gravity šetâb-e gerâni Fr.: accélération de la gravité The acceleration that an object experiences because of gravity when it falls freely close to the surface of a massive body, such as a planet. Same as → gravitational acceleration. → acceleration; → gravity. |
acceleration parameter pârâmun-e šetâb Fr.: paramètre d'accéleration A measure of the departure from a constant rate of the acceleration of the Universe, expressed by: q(t) = R(t)R^{ ..}(t)/R^{ .}^{2}(t), where R(t) represents the size of the Universe at time t. Traditionally, a negative sign is inserted in the above equation for the → deceleration parameter. → acceleration; → parameter. |
accelerator šetâbgar (#) Fr.: accélérateur A machine which accelerates charged atomic (ions of various elements) or subatomic particles (usually electrons and protons) to high energies. → cyclotron; → synchrotron. Accelerator, from accelerate, → acceleration, + -or agent suffix, from M.E. -or, -our, from O.F. -eor, -eur, from L. -or. Šetâbgar, from šetâb→ acceleration + -gar agent suffix, → -or. |
adiabatic temperature gradient zine-ye damâ-ye bidarrow Fr.: gradient de température adiabatique The temperature gradient defining the → radiative equilibrium condition in a region. It is expressed as: dT/dr = (1 - 1/ γ)((T / P)(dP / dr), where T and P are temperature and pressure, dT / dr and dP / dr temperature and pressure gradients respectively, and γ = C_{P} / C_{V}. For radiative equilibrium to be stable against → convection, the actual temperature gradient must be less than the adiabatic temperature gradient, i.e. |dT /dr|_{rad} < |dT /dr|_{ad}. See also → Schwarzschild's criterion. → adiabatic; → temperature; → gradient. |
agglomerate 1) bargolemidan; 2) bargolemidé; 3) bargolem Fr.: 1) agglomérer; 2,3) aggloméré 1) (v.) To collect or gather into a cluster or mass. From L. agglomeratus, p.p. of agglomerare "to wind or add onto a ball," from → ad- "to" + glomerare to "wind up in a ball," from glomus (genitive glomeris) "ball of yarn," globus "globe;" PIE *gel- "to make into a ball." Bargolemidan, from suffix bar- "to, on, upon," + golem, from Lori, Laki golemâ, golama "curd, obtained from milk by coagulation, used to make cheese," Lori golem "stagnating water," Sangesari, Semnâni, Sorxe-yi, Lâsgardi golma, "boll, i.e. the rounded seed capsule of plants such as cotton," + -idan infinitive suffix. |
agglomeration bargolemeš Fr.: agglomération 1) A jumbled cluster or mass of varied parts. Verbal noun of → agglomerate. |
Alderamin (α Cephei) Zerâ'-e Yamin Fr.: Alderamin The brightest star in → Cepheus and a → subgiant star of apparent visual magnitude 2.44. Its → spectral type is A7 and distance 49 → light-years. Alderamin, from Ar. al dhirâ' al-yamin "right arm" (of Cepheus), from Ar. dhirâ' "arm" + yamin "right". Zerâ'-e Yamin, from Ar. al dhira al-yamin. |
Alpheratz (α Andromedae) Ra's-ol-Mosalsalé Fr.: Alphératz The brightest star in → Andromeda with a visual magnitude of 2.07. Alpheratz is a blue → subgiant star of spectral type B8 IV lying at a distance of about 97 → light-years. It is particularly remarkable because of the unusual strength of mercury and manganese absorption lines in its spectrum. Other names for this star are Alpherat, Sirrah, or Sirah.
These names derive from Ar. As-Surrat al-Faras
( |
alteration degarguni, degarguneš Fr.: altération 1) The act or process of altering; the state of being altered. Verbal noun of → alter. |
Amazonian era dowrân-e Âmâzoni Fr.: ère amazonienne The current geologic era on Mars that began around 2 billion to 3 billion years ago. It is characterized by lower geologic activity such as volcanism and only occasional releases of underground water. A dry environment with a very thin atmosphere in which water can only exist as a solid or a gas, not as a liquid. → Noachian era; → Hesperian era. Named for the young lava-covered plains called Amazonia Planitia. → era. |
angular acceleration šetâb-e zâviye-yi Fr.: accélération angulaire The rate of change of → angular velocity. It is equal to the → first derivative of the → angular velocity: α = dω/dt =d^{2}θ/dt^{2} = a_{t}/r, where θ is the angle rotated, a_{t} is the linear tangential acceleration, and r is the radius of circular path. → angular; → acceleration. |
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