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: 225 Search : for
cosmic star formation peak
  چکاد ِ کیهانی ِ دیسش ِ ستارگان   
cakâd-e keyhâni-ye diseš-e setâregân

Fr.: pic de formation stellaire cosmique   

A crucial period in the history of the → Universe, when the bulk of stars in massive galaxies were likely formed. Observations of young stars in distant galaxies at different times in the past have indicated that the → star formation rate peaked at the → redshift of z ~ 2, some 10 billion years ago, before declining by a factor of around ten to its present value (P. Madau & Dickinson, 2014, arXiv:1403.0007).

cosmic; → star; → formation; → peak.

Coulomb force
  نیروی ِ کولن   
niru-ye Coulomb (#)

Fr.: force de Coulomb   

An attractive or repulsive → electrostatic force between objects bearing electric charge, as described by → Coulomb's law. If the charges are of opposite sign, then the force is attractive; if thy are of the same sign, the force is repulsive.

Coulomb; → force.

deform
  ۱) وادیسیدن؛ ۲) وادیساندن   
1) vâdisidan; 2) vâdisândan

Fr.: 1) se déformer; 2) déformer   

1) To undergo → deformation.
2) To change the form or shape of. → deformable, → deformed, → deformation.

From O.Fr. déformer, from L. deformare "to disfigure," from → de- + → form.

Vâdisidan, vâdisândan infinitive from vâdis, from vâ-, → de-, + dis, → form.

deformable
  وادیسیدنی   
vâdisidani

Fr.: déformable   

Capable of being → deformed. → deformable mirror

deform + → -able.

deformable mirror
  آینه‌ی ِ وادیسیدنی   
âyene-ye vâdisidani

Fr.: miroir déformable   

A very thin mirror whose shape can be changed by the force applied by many small pistons behind the mirror. Such a mirror is used in the → adaptive optics technique to correct the → wavefront affected by the → atmospheric turbulence. See also → tip-tilt mirror.

deformable; → mirror.

deformation
  وادیس، وادیسش، وادیسانش   
vâdis, vâdiseš, vâdisâneš

Fr.: déformation   

Altering in the size or shape of a body. See also → deformable.

Verbal noun of → deform.

deformed
  وادیسیده   
vâdisidé

Fr.: déformé   

Having the → form → changed.

Past participle of → deform.

Descartes' formula
  دیسول ِ دکارت   
disul-e Descartes

Fr.: formule de Descartes   

A formula that gives the position of an image formed by highly → paraxial rays from a → spherical mirror. It is quite accurately given by: 1/xo + 1/xi = 2/xC, where xo is the distance along the → principal axis from the mirror to the object, xi is the distance from mirror to image, and xC is the distance from the mirror to its center of curvature. Any distance measured on the same side of the mirror as the reflecting surface is positive; on the other side, negative. Thus for a → concave mirror  xC is positive; for a → convex mirror, negative.

Descartes; → formula.

dimensional formula
  دیسول ِ وامونی   
disul-e vâmuni

Fr.: formule dimensionnelle   

Symbolic representation of the definition of a physical quantity obtained from its units of measurement. For example, with M = mass, L = length, T = time, area = L2, velocity = LT-1, energy = ML2T-2. → dimensional analysis.

dimensional; → formula.

elastic deformation
  وادیسش ِ کشایند   
vâdiseš-e kešâyand

Fr.: déformation élastique   

A deformation of a → solid body in which the change (→ strain) in the relative position of points in the body disappears when the deforming stress is removed. See also → elastic limit.

elastic; → deformation.

electromagnetic force
  نیروی ِ برقامغناتی   
niru-ye barqâmeqnâti

Fr.: force électromagnétique   

The fundamental force that is associated with electric and magnetic fields. One of the four fundamental forces of nature, it is carried by photons.

electromagnetic; → force.

electromotive force (EMF)
  نیروی ِ برقران   
niru-ye barqrân (#)

Fr.: force électromotrice   

The force, analogous to a pressure, which maintains a flow of electricity through a closed circuit. It is the algebraic sum of the → potential differences acting in the circuit. The unit of electromotive force is the → volt.

From → electro- + motive, from M.E., from M.Fr., from O.Fr. motif, from M.L. motivus "moving, impelling," from L. motus, p.p. of movere "to move," → motion; → force.

Niru, → force; barqrân, literally "driving electricity," from barq, → electro- + rân present stem of rândan, → drive.

electroweak force
  نیروی ِ برقا نزار، ~ برقا کمزور   
niru-ye barqânezâr, ~ barqâkamzur

Fr.: force électrofaible   

The force that takes part in an → electroweak interaction.

electroweak; → force.

empirical formula
  دیسول ِ آروینی   
disul-e ârvini

Fr.: formule empirique   

1) In physics, a mathematical equation that predicts observed results, but has no known theoretical basis to explain why it works.
2) In chemistry, a simple expression of the relative number of each type of atom in a chemical compound.

empirical; → formula

Euler's formula
  دیسول ِ اویلر   
disul-e Euler

Fr.: formule d'Euler   

A formula which expresses an → exponential function with an → imaginary number  → exponent in terms of → trigonometric functions:
e = cos θ + i sinθ,
e-iθ = cos θ - i sinθ,
cosθ = (e + e-iθ)/2,
sinθ = (e - e-iθ)/2i.
In the particular case of θ = π, Euler's formula becomes: eiπ + 1 = 0, which is considered by many mathematicians to be the most elegant mathematical equation. → mathematical elegance.

Euler; → formula.

exchange force
  نیروی ِ گهولی   
niru-ye gahuli

Fr.: force d'échange   

The force that governs the exchange of particles in the interaction between bodies. → exchange particle.

exchange, → force.

feedforward
  پیش‌خورد   
pišxord

Fr.:   

In a self-regulatory system, monitoring a disturbance before it enters the → system to apply corrections before the disturbance has influenced the system. See also → feedback.

feed; → forward.

field of force
  میدان ِ نیرو   
meydân-e niru (#)

Fr.: champ de force   

The region of → space surrounding a body, such as a mass of → matter, a → charged particle, or a → magnet, within which it can exert a → force on another similar body not in contact with it.

field; → force.

for
  برای   
barâye (#)

Fr.: pour   

A preposition used to indicate the object or purpose of an action.

M.E., from O.E. for "before, in the sight of, in the presence of" (source also of Old Saxon furi "before," Old Frisian for, Middle Dutch vore, Dutch voor "for, before;" German für "for;" Danish for "for," før "before;" Gothic faur "for," faura "before"), from PIE root *per- "forward," hence "in front of, before," etc.

Barâye "because of," related to Pers. cerâ "for what reason, why?," irâ "for this reason, therefore," zirâ "because, on account of;" also rây "opinion, consult," Mid.Pers. râd, rây "because of, for the sake of, on behalf of;" O.Pers. "reason, cause," in rādiy "for this reason," → reason.

Forbes effect
  اسکر ِ فوربز   
oskar-e Forbes

Fr.: effet Forbes   

Increased reddening and monochromaticity of light as the path length in the air increases.

After the Scottish physicist James David Forbes (1809-1868); → effect.

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