# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

Homepage

Number of Results: 9 Search : transformation
 affine transformation   ترادیس ِ کروَن   tarâdis-e karvanFr.: transformation affine   Any → transformation preserving → collinearity.→ affine; → transformation. color transformation   ترادیس ِ رنگ   tarâdis-e rangFr.: transformation de couleur   Empirical mathematical transformation applied to the observed magnitudes in order to convert them into a standard system, or into a different system.→ color; → transformation. Galilean transformation   ترادیس ِ گالیله‌ای   tarâdis-e Gâlile-yi (#)Fr.: transformation galiléenne   The method of relating a measurement in one → reference frame to another moving with a constant velocity with respect to the first within the → Newtonian mechanics. The Galilean transformation between the coordinate systems (x,y,z,t) and (x',y',z',t') is expressed by the relations: x' = x - vt, y' = y, z' = z. Galilean transformations break down at high velocities and for electromagnetic phenomena and is superseded by the → Lorentz transformations. gauge transformation   ترادیس ِ گز   tarâdis-e gaz (#)Fr.: transformation de jauge   A change of the fields of a gauge theory that does not change the value of any measurable quantity.→ gauge; → transformation. Legendre transformation   ترادیسش ِ لوژاندر   tarâdiseš-e LegendreFr.: transformation de Legendre   A mathematical operation that transforms one function into another. Two differentiable functions f and g are said to be Legendre transforms of each other if their first derivatives are inverse functions of each other: df(x)/dx = (dg(x)/dx)-1. The functions f and g are said to be related by a Legendre transformation. Lorentz transformation   ترادیس ِ لورنتز   tarâdis-e LorentzFr.: transformation de Lorentz   A set of linear equations that expresses the time and space coordinates of one → reference frame in terms of those of another one when one frame moves at a constant velocity with respect to the other. In general, the Lorentz transformation allows a change of the origin of a coordinate system, a rotation around the origin, a reversal of spatial or temporal direction, and a uniform movement along a spatial axis. If the system S'(x',y',z',t') moves at the velocity v with respect to S(x,y,z,t) in the positive direction of the x-axis, the Lorentz transformations will be: x' = γ(x - vt), y' = y, z' = z, t' = γ [t - (vx/c2)], where c is the → velocity of light and γ = [1 - (v/c)2]-1/2. For the special case of velocities much less than c, the Lorentz transformation reduces to → Galilean transformation. similarity transformation   ترادیسش ِ همانندی   tarâdiseš-e hamânandiFr.: transformation de similarité   1) A transformation that preserves angles and changes all distances in the same ratio. 2) A transformation of the form B = X-1AX relating two → square matrices A and B. transformation   ترادیسش، ترادیس   tarâdiseš (#), tarâdis (#)Fr.: transformation   1) The act or process of transforming. The state of being transformed. 2) The relationship between description of a physical phenomenon in one → reference frame to another. → Galilean transformation; → Lorentz transformation. 3) Math.: The act, process, or result of transforming or mapping.Verbal noun of → transform. unitary transformation   ترادیس ِ یکایی، ~ یکانی   tarâdis-e yekâyi, ~ yekâniFr.: transformation unitaire   A transformation whose reciprocal is equal to its Hermitian conjugate.