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

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 9 Search : Lorentz
 local Lorentz invariance   ناورتایی ِ لورنتز ِ محلی   nâvartâyi-ye Lorentz-e mahaliFr.: invariance de Lorentz locale   → local; → Lorentz; → invariance. Lorentz   لورنتز   LorentzFr.: Lorentz   Contraction of the full name of Hendrik Antoon Lorentz (1853-1928), a Dutch physicist, who made important contribution to physics. He won (with Pieter Zeeman) the Nobel Prize for Physics in 1902 for his theory of electromagnetic radiation, which, confirmed by findings of Zeeman, gave rise to Albert Einstein's special theory of relativity. Lorentz contraction   ترنگش ِ لورنتز   terengeš-e LorentzFr.: contraction de Lorentz   The decrease in the length of a body moving in the direction of its length as measured by an observer situated in that direction. The shortening factor is [1 - (v/c)2]1/2, where v is the relative velocity and c light speed.→ Lorentz; → contraction. Lorentz factor   کروند ِ لورنتز   karvand-e LorentzFr.: facteur de Lorentz   In → special relativity, an important parameter which appears in several equations, including → time dilation, → length contraction, and → relativistic mass. It is defined as γ = 1 / [1 - (v/c)2]1/2 = dt/dτ, where v is the velocity as observed in the reference frame where time t is measured, τ is the proper time, and c the → velocity of light. Same as Lorentz γ factor.→ Lorentz; → factor. Lorentz force   نیروی ِ لورنتز   niru-ye Lorentz (#)Fr.: force de Lorentz   The force acting upon a → charged particle as it moves in a → magnetic field. It is expressed by F = q.v x B, where q is the → electric charge, v is its → velocity, and B the → magnetic induction of the field. This force is perpendicular both to the velocity of the charge and to the magnetic field. The magnitude of the force is F = qvB sinθ, where θ is the angle between the velocity and the magnetic field. This implies that the magnetic force on a stationary charge or a charge moving parallel to the magnetic field is zero. The direction of the force is given by the → right-hand rule.→ Lorentz; → force. Lorentz invariance   ناورتایی ِ لورنتز   nâvartâyi-ye LorentzFr.: invariance de Lorentz   Of a physical law, invariance with respect to a → Lorentz transformation.→ Lorentz; → invariance. Lorentz resonance   باز‌آوایی ِ لورنتز   bâzâvâyi-ye LorentzFr.: résonance de Lorentz   A repeated electromagnetic force on an electrically charged ring particle, nudging the particle in the same direction and at the same point in its orbit. Lorentz resonances are especially important for tiny ring particles whose charge-to-mass ratio is high and whose orbit periods are a simple integer fraction of the rotational period of the planet's magnetic field (Ellis et al., 2007, Planetary Ring Systems, Springer).→ Lorentz; → resonance. 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. Lorentzian profile   فراپال ِ لورنتزی   farâpâl-e LorentziFr.: profil lorentzien   A spectral profile in which the intensity distribution follows a specific mathematical function (Lorentz or Cauchy probability). Compared to the normal or Gaussian profile, Lorentzian has a pointed peak and more important wings.→ Lorentz; → profile.