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
line of force
  خط ِ نیرو   
khatt-e niru (#)

Fr.: ligne de force   

One of many → imaginary lines whose direction at all → points along its length is that of the electric or → magnetic field at those points. In → electric fields the lines of force are directed toward → negative charges and point away from → positive charges. In magnetic fields the lines of force are directed from the → north pole to the → south pole.

line; → force.

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 transformation
  ترادیس ِ لورنتز   
tarâdis-e Lorentz

Fr.: 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.

Lorentz; → transformation.

lunar formation
  دیسش ِ مانگ   
diseš-e Mâng

Fr.: formation de la Lune   

See → Moon formation.

lunar; → formation.

Lyman alpha forest
  جنگل ِ لایمن-‌آلفا   
jangal-e Lyman-alpha (#)

Fr.: forêt Lyman alpha   

The appearance of many differentially → redshiftedLyman alpha lines in → absorption in a → quasar's → spectrum, caused by intervening → hydrogen clouds along our → line of sight to the quasar.

Lyman; → forest.

Magnus force
  نیروی ِ مگنوس   
niru-ye Magnus

Fr.: force de Magnus   

The force exerted on a spinning object moving through a fluid medium in virtue of → Bernoulli's theorem. The Magnus force can deviate a football from its path when a player strikes it so that it spins about an axis perpendicular to the flow of air around it. As the spinning ball moves through the air, it will create a pressure difference between its two sides. The air travels faster relative to the centre of the ball where its periphery is moving in the same direction as the airflow. This reduces the pressure according Bernoulli's theorem. The opposite effect happens on the other side of the ball, where the air travels slower relative to the centre of the ball. There is therefore an imbalance in the forces that will curve the ball's trajectory.

Named after Heinrich Gustav Magnus (1802-1870), a German chemist and physicist; → force.

mass formula
  دیسول ِ جرم   
disul-e jerm

Fr.: formule de masse   

An → equation expressing the → atomic mass of a → nuclide as a function of its → mass number and the → atomic mass unit.

mass; → formula.

Mikulski Archive for Space Telescopes (MAST)
  بایگانی ِ میکالسکی برای ِ تلسکوپهای ِ فضایی   
Bâygâni-ye Mikulski barâye teleskophâ-ye fazâyi

Fr.: Archive Mikulski pour télescopes spatiaux   

A → NASA funded project to support and provide to the astronomical community a variety of astronomical data archives, with the primary focus on scientifically related data sets in the optical, ultraviolet, and near-infrared parts of the spectrum. MAST is a huge database that contains astronomical observations of stars, planets and galaxies from 16 separate NASA space science missions, including the Hubble Space Telescope. It is located at the Space Telescope Science Institute (STScI).

In honor of senator Barbara A. Mikulski for her active support for science, NASA, and the astrophysics community; → archive; → space; → telescope.

Modules for Experiments in Stellar Astrophysics (MESA)
     
MESA

Fr.: MESA   

An open-source, one-dimensional astrophysical code which is capable of calculating the evolution of stars in a wide range of environments. It works according to the → Henyey method and uses many modules that deal with various aspects of the theoretical models, such as the → equation of state (EOS), → nuclear reaction networks, → chemical composition, micro-physics, or macro-physics. The EOS and corresponding opacities or nuclear networks are provided in tabulated formats and can be selected by the user, while the micro-physics and macro-physics can be controlled by inlists of relevant parameters and settings (Paxton et al. 2015, ApJS 220, 15 and references therein).

module; → experiment; → stellar; → astrophysics.

molecular formula
  دیسول ِ مولکولی   
disul-e molekuli

Fr.: formule moléculaire   

The formula of a chemical compound, showing the kind and arrangement of atoms.

molecular; → formula.

moment of force
  گشتاور   
gaštâvar (#)

Fr.: moment, couple   

A measure of a force's tendency to cause a body to → rotate about a specified → axis. It is given by the force times the perpendicular → distance of the → line of action from the axis. Same as → torque

moment; → force.

Moon formation
  دیسش ِ مانگ   
diseš-e Mâng

Fr.: formation de la Lune   

Any of several theories about how the → Moon originated, among which: → fission theory, → capture theory, → co-formation theory, and → giant impact hypothesis. The model that is best supported by all the available data is the giant impact hypothesis. See also → canonical model.

lunar; → formation.

Newton-Leibniz formula
  دیسول ِ نیوتن-لایبنیتس   
disul-e Newton-Leibniz

Fr.: formule de Newton-Leibniz   

The formula expressing the value of a → definite integral of a given function over an interval as the difference of the values at the end points of the interval of any → antiderivative of the function: ∫f(x)dx = F(b) - F(a), summed from x = a to x = b.

Named after Isaac → Newton and Gottfried Wilhelm Leibniz (1646-1716), who both knew the rule, although it was published later; → formula.

nuclear force
  نیروی ِ هسته‌ای   
niru-ye haste-yi (#)

Fr.: force nucléaire   

The attractive force which acts between nucleons when they are extremely close together (closer than 10-13 cm).

nuclear; → force.

Nyquist formula
  دیسول ِ نیکویءیست   
disul-e Nyquist

Fr.: formule de Nyquist   

The mean square noise voltage across a resistance in thermal equilibrium is four times the product of the resistance, Boltzmann's constant, the absolute temperature, and the frequency range within which the voltage is measured. → Johnson-Nyquist noise.

Named after Harry Nyquist (1889-1976), a Swedish-born American physicist, who made important contributions to information theory. → Johnson-Nyquist noise; → formula.

perform
  پرگالیدن   
pergâlidan

Fr.: exécuter, accomplir   

1) To carry out; → execute; do.
2) To go through or execute in the proper, customary, or established manner (Dictionary.com).

M.E. parformen, from Anglo-Fr. performer, from O.Fr. parfornir "to do, carry out, finish, accomplish," from par- "completely," → per-, + fornir "to provide."

Pergâlidan, from Kurd. (Sanandaj) pergâl "work, doing; order, command," ultimately from Proto-Ir. *parikar-, from *pari- "through, throughout; thoroughly" (O.Pers. pariy "around, about;" Av. pairi "around, over") + *kar- "to do;" Pers. kar-, variants kâr, gar, gâr, → work.

performance
  پرگال   
pergâl

Fr.: 1, 3) représentation, interprétation; 2) fonctionnement, performance; exécution   

1) The act of performing a ceremony, play, piece of music, etc.
2) The execution or accomplishment of work, acts, feats, etc.
3) A musical, dramatic, or other entertainment presented before an audience (Dictionary.com).

perform; → -ance.

performative
  ۱) پرگالی؛ ۲) واپش ِ پرگالنده   
1) pergâli; 2) vâpeš-e pergalandé

Fr.: 1) performatif; d'interprétation; 2) performativité   

1) Relating to or of → performance, especially of dramatic or artistic performance.
2) A → performative utterance.

perform; → -ive.

performative utterance
  واپش ِ پرگالنده   
vâpeš-e pergâlandé

Fr.: performativité   

A sentence or expression which is not only describing a given reality, but actually does or accomplishes something. For example "I now declare you husband and wife" (when uttered by the authorized officiator during a marriage ceremony).

performative; → utterance.

performer
  پرگالگر، پرگالنده   
pergâlgar, pergâlandé

Fr.: interprète, acteur, artiste   

1) Someone who performs in front of an audience, for example an actor or musician.
2) Someone who does something with a particular amount of success (Macmillan Dictionary).

perform; → -er.

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