An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 69 Search : on-
Newton-Maxwell incompatibility
  ناسازگاری ِ نیوتن-ماکسول   
nâsâzgâri-ye Newton-Maxwell

Fr.: incompatibilité entre Newton et Maxwell   

The incompatibility between → Galilean relativity and Mawxell's theory of → electromagnetism. Maxwell demonstrated that electrical and magnetic fields propagate as waves in space. The propagation speed of these waves in a vacuum is given by the expression c = (ε00)-0.5, where ε0 is the electric → permittivity and μ0 is the magnetic → permeability, both → physical constants. Maxwell noticed that this value corresponds exactly to the → speed of light in vacuum. This implies, however, that the speed of light must also be a universal constant, just as are the electrical and the magnetic field constants! The problem is that → Maxwell's equations do not relate this velocity to an absolute background and specify no → reference frame against which it is measured. If we accept that the principle of relativity not only applies to mechanics, then it must also be true that Maxwell's equations apply in any → inertial frame, with the same values for the universal constants. Therefore, the speed of light should be independent of the movement of its source. This, however, contradicts the vector addition of velocities, which is a verified principle within → Newtonian mechanics. Einstein was bold enough to conclude that the principle of Newtonian relativity and Maxwell's theory of electromagnetism are incompatible! In other words, the → Galilean transformation and the → Newtonian relativity principle based on this transformation were wrong. There exists, therefore, a new relativity principle, → Einsteinian relativity, for both mechanics and electrodynamics that is based on the → Lorentz transformation.

Newton; → Maxwell; → incompatibility.

Newton-Raphson method
  روش ِ نیوتن-رفسون   
raveš-e Newton-Raphson

Fr.: méthode de Newton-Raphson   

A method for finding roots of a → polynomial that makes explicit use of the → derivative of the function. It uses → iteration to continually improve the accuracy of the estimated root. If f(x) has a → simple root near xn then a closer estimate to the root is xn + 1 where xn + 1 = xn - f(xn)/f'(xn). The iteration begins with an initial estimate of the root, x0, and continues to find x1, x2, . . . until a suitably accurate estimate of the position of the root is obtained. Also called → Newton's method.

Newton found the method in 1671, but it was not actually published until 1736; Joseph Raphson (1648-1715), English mathematician, independently published the method in 1690.

non-
  نا-   
nâ- (#)

Fr.: non-   

A prefix meaning "not."

From O.Fr. non-, from L. non "not," from Old L. noenum "not one;" in some cases perhaps from M.E. non "not" (adj.), from O.E. nan.

Nâ- "no, not," variants na, ni, ma- (prohibitive) "not;" from Mid.Pers. nê, ma "no, not;" O.Pers. naiy, nai "not;" Av. nôit, naē "not;" cf. Skt. "not;" cf. L. ne-, in-, un-; Gk. ni; Lith. ; O.C.S. ne "not;" PIE *ne-.

non-algebraic function
  کریای ِ ناجبری   
karyâ-ye nâjabri

Fr.: fonction non algébrique   

A → transcendental function. Examples are: exponential, logarithmic, and trigonometric functions.

non-; → algebraic + → function.

non-baryonic dark matter
  ماده‌ی ِ سیاه ِ ناباریونی   
mâde-ye siyâh-e nâbâriyoni

Fr.: matière noire non-baryonique   

Dark matter composed of → non-baryonic particles.

non-; → baryonic; → dark; → matter.

non-baryonic matter
  مادّه‌ی ِ ناباریونی   
mâdde-ye nâbâriyoni (#)

Fr.: matière non-baryonique   

Matter that, unlike the ordinary matter, is not made of baryons (including the neutrons and protons). It is proposed as a possible constituent of dark matter.

non-; → baryonic matter.

non-coherent radiation
  تابش ِ ناهمدوس   
tâbeš-e nâhamdus (#)

Fr.: rayonnement incohrént   

Radiation having waves that are out of phase in space and/or time; radiation which is not → coherent.

non-; → coherent; → radiation.

non-contingent
  نا-آمرسان   
nâ-âmarsân

Fr.: non contingent   

Describing a → proposition that is either → true in every possible circumstance or → false in every possible circumstance. A proposition that is not → contingent.

non-; → contingent.

non-dispersive medium
  مدیم ِ ناپاشنده   
madim-e nâpâšandé

Fr.: milieu non dispersif   

A medium in which the → phase velocity is independent of frequency.

non-; → dispersive; → medium.

non-Euclidean geometry
  هندسه‌ی ِ نا-اقلیدوسی   
hendese-ye nâ-oqlidosi (#)

Fr.: géométrie non-euclidienne   

Any of several geometries which do not follow the postulates and results of Euclidean geometry. For example, in a non-Euclidean geometry through a point several lines can be drawn parallel to another line. Or, the sum of the interior angles of a triangle differs from 180 degrees. According to Einstein's general relativity theory, gravity distorts space into a non-Euclidean geometry.

non-; → Euclidean geometry.

non-hierarchical multiple system
  راژمان ِ بستایی ِ ناپایگانی   
râžmân-e bastâyi-ye nâpâygâni

Fr.: système multiple non hiérarchique   

A → multiple star system that lacks the characteristics of a → hierarchical multiple system.

non-; → hierarchical; → multiple; → system.

non-ideal magnetohydrodynamics (MHD)
  مغنات-و-هیدروتوانیک ِ نا-آرمانی، ~ نا-مینه‌وار   
meqnâtohidrotavânik-e nâ-ârmâni, ~ nâ-minevâr

Fr.: magnétohydrodynamique non idéale   

A → magnetohydrodynamics approach dealing with → plasmas which is an improvement with respect to → ideal magnetohydrodynamics. Non-ideal magnetohydrodynamics allows for a drift between particles, redistributing the → magnetic flux and acting on both the → angular momentum and magnetic flux conservation issues.

non-ideal; → magnetohydrodynamics.

non-inertial frame
  چارچوب ِ نالختی‌ناک، ~ نالختی‌مند   
cârcub-e nâlaxtinâk, ~ nâlaxtimand

Fr.: référentiel non inertiel, ~ non galiléen   

Any frame of reference in which the law of inertia does not apply, such as in accelerating and rotating frames. For example, the Earth is a non-inertial frame because it is rotating about its axis. But the rotation is so slow that the associated acceleration is negligible compared to other accelerations commonly encountered in everyday life. However, the non-inertial nature of the Earth appears in, e.g., the → Coriolis effect. → inertial reference frame.

non-; → inertial; → frame.

non-ionized
  نایونیده   
nâyonidé (#)

Fr.: non ionisé   

Not ionized, → neutral.

non-; → ionized.

non-local thermodynamic equilibrium (NLTE)
  ترازمندی ِ گرماتوانیک ِ نامحلی   
tarâzmandi-ye garmâtavânik-e nâmahali

Fr.: hors équilibre thermodynamique local   

A physical condition in which the assumption of the → local thermodynamic equilibrium does not hold.

non-; → local thermodynamic equilibrium.

non-luminous matter
  ماده‌ی ِ ناتابان   
mâdde-ye nâtâbân

Fr.: matière non lumineuse   

Not ordinary matter. Same as → dark matter.

non-; → luminous; → matter.

non-radial pulsation
  تپش ِ ناشعاعی   
tapeš-e nâšo'âyi

Fr.: pulsation non-radiale   

A type of stellar pulsation in which waves run in different directions on and beneath the surface of a star.

non-; → radial; → pulsation.

non-radiative process
  فراروند ِ ناتابشی   
farâravand-e nâtâbeši

Fr.: processus non radiatif   

An process in which an excited state returns to the ground state without emitting radiation. → radiative process.

non-; → radiative; → process.

non-relativistic
  ناباز‌آنیگی‌مند   
nâ-bâzânigi-mand

Fr.: non-relativiste   

Not concerned with or based on the → theory of relativity. See also:
non-relativistic electron, → non-relativistic mechanics, → relativistic.

non-; → relativistic.

non-relativistic electron
  الکترون ِ ناباز‌آنیگی‌مند   
elektron-e nâ-bâzânigi-mand

Fr.: électron non-relativiste   

An electron that does not experience relativistic effects since its velocity is very small compared to that of light.

non-relativistic; → electron.

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