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: 584
theory
  نگره   
negaré (#)

Fr.: théorie   

A coherent set of verified facts, propositions, or principles analyzed in their relation to one another and used to explain and predict phenomena, e.g. the → theory of relativity. The criterion of the scientific status of a theory is its → falsifiability, → refutability, or → testability. See also → hypothesis, → model.

From L.L. theoria, from Gk. theoria "contemplation, speculation, a looking at, things looked at," from theorein "to consider, view, look at," from theoros "spectator," from thea "a view" + horan "to see."

Negaré, from negar present stem of negaridan, negaristan "to look, observe;" Mid.Pers. nigeridan, niger-, nikiritan, nikir- "to look, to watch, to notice, to consider;" ultimately from Proto-Iranian *ni-kar-, from *ni- "down, in, into," → ni- (PIE), + *kar- "to observe, to consider;" cf. Av. kar- "to remember; to impress on memory;" Skt. kal- "to observe, consider," kalayati "considers, observes;" Mid.Pers. kartan "to establish; to declare; to found," (h)angârtan "to consider, to bear in mind, to regard as," us-kâritan "to consider, deliberate, discuss," sikâl, sigâl "thought;" Mod.Pers. engâridan, engâštan "to suppose," segâl "thought," segâlidan "to think, to resolve to injure, to deceive."

theory of everything (TOE)
  نگره‌ی ِ همه چیز   
negare-ye hamé ciz

Fr.: théorie du tout   

Any theory that attempts to describe all the forces of nature including gravity in a single mathematical formalism; e.g. → grand unified theory. → string theory.

theory; every; M.E. every, everich; O.E. æfre ælc "ever each;" → thing.

Negaré, → theory; hamé, → all; ciz, → thing.

theory of relativity
  نگره‌ی ِ بازانیگی   
negare-ye bâzânigi

Fr.: théorie de la relativité   

Any of the two theories put forward by Albert Einstein: → special relativity (1905) and → general relativity (1916).

theory; → relativity;

therm
  ترم   
therm

Fr.: therm   

Any of several commercial units of heat energy, as one equivalent to 106 calories.

From Gk. therme "heat," → thermal.

thermal
  گرمایی   
garmâ-yi (#)

Fr.: thermique   

Of, pertaining to, or caused by heat or temperature.

From M.Fr. thermal, from Gk. therme "heat," cognate with Pers. garm "warm," as below.

Garmâyi, adj. of garmâ "heat, warmth," from Mid.Pers. garmâg; O.Pers./Av. garəma- "hot, warm;" cf. Skt. gharmah "heat;" cognate with Gk. therme, thermos, as above; PIE *ghworm-/*ghwerm- "warm."

thermal agitation
  ژیلش ِ گرمایی   
ſileš-e garmâyi

Fr.: agitation thermique   

1) The random movement of the molecules of a substance, the energy of which is, by kinetic theory, synonymous with the heat content of the substance.
2) Solid state physics: The random motion of free electrons in a conductor due to heat energy.

thermal; → agitation.

thermal bremsstrahlung
  لگام-تابش ِ گرمایی   
legâm-tâbeš-e garmâyi

Fr.: bremsstrahlung thermique   

The emission of electromagnetic radiation from high temperature plasma, produced as electrons are deviated by positive ions. Same as → free-free emission

thermal; → bremsstrahlung.

thermal conduction
  هازش ِ گرمایی   
hâzeš-s garmâyi

Fr.: conduction thermale   

A process that occurs in a medium where a → temperature gradient exists: dQ = -κ(dT/dx)dA.dt, where dQ is the amount of heat passing through the time dt across an area dA in the direction of the normal x to this area and toward the reduction in temperature, κ is the → thermal conductivity, and (dT/dx) the temperature gradient.

thermal; → conduction.

thermal conductivity
  هازندگی ِ گرمایی   
hâzandegi-ye garmâyi

Fr.: conductivité thermale   

In → thermal conduction, the amount of heat passing across unit area per unit time and per unit → temperature gradient.

thermal; → conductivity.

thermal detector
  آشکارگر ِ گرمایی   
âškârgar-e garmâyi

Fr.: détecteur thermique   

A detector that senses the change of temperature due to the absorption of photons.

thermal; → detector.

thermal diffusion
  پخش ِ گرمایی   
paxš-e garmâyi

Fr.: diffusion thermique   

A physical process resulting from → temperature gradients in stellar interiors, whereby more highly charged and more massive chemical species are concentrated toward the hottest region of the star, its center. Therefore, thermal diffusion and → gravitational settling tend to make heavier species sink relative to the light ones.

thermal; → diffusion.

thermal emission
  گسیل ِ گرمایی   
gosil-e garmâyi (#)

Fr.: émission thermique   

thermal radiation.

thermal; → emission.

thermal energy
  کاروژ ِ گرمایی   
kâruž-e garmâyi

Fr.: énergie thermique   

1) The energy in the form of heat emitted by an object by virtue of its temperature.
2) The total potential and kinetic energies associated with the random motions of the particles of a material. The quantity of thermal energy possessed by a body determines its temperature. The thermal energy which is absorbed, given up, or transferred from one material to another is heat.
3) The characteristic energy of → thermal neutrons at room temperature, about 0.025 eV.

thermal; → energy.

thermal equilibrium
  ترازمندی ِ گرمایی   
tarâzmandi-ye garmâyi (#)

Fr.: équilibre thermique   

In thermodynamics, the state of a system all parts of which have attained a uniform temperature and no net heat exchange is taking place between it and its surroundings. If two bodies are in thermal equilibrium, they have the same temperature. Thermal equilibrium is the central criterion of the → zeroth law of thermodynamics. See also → local thermodynamic equilibrium (LTE).

thermal; → equilibrium.

thermal excitation
  بر‌انگیزش ِ گرمایی   
barangizeš-e garmâyi

Fr.: excitation thermique   

A process in which collisions that occur between particles cause atoms or molecules to obtain additional kinetic energy.

thermal; → excitation.

thermal expansion
  سپانش ِ گرمایی   
sopâneš-e garmâyi

Fr.: expansion thermique   

The change in dimensions of a material resulting from a change in temperature.

thermal; → expansion.

thermal gradient
  زینه‌ی ِ گرمایی   
zine-ye garmâyi

Fr.: gradient thermique   

A vector quantity that depends on the distribution of temperature in three dimensions with respect to a given point. The magnitude and orientation of the maximum thermal gradient are given by: ∇T = (∂T/∂x)i + (∂T/∂y)j + (∂T/∂z)k, where T is the temperature distribution function in three dimensions, and i, j, and k are the unit vectors along the x, y, and z axes defining the temperature field. Same as → temperature gradient.

thermal; → gradient.

thermal hopping
  کپ ِ گرمایی   
kop-e garmâyi

Fr.: saut thermique   

A mechanism for the → transport of → electrons which occurs when the → Fermi level lies below a low but wide energy → barrier. The → tunneling probability across the barrier is considerably suppressed due to the width of the barrier. However, at higher temperatures, the electron can raise its energy with the assistance of a vibrational mode. The electron is said to hop from one side of the barrier to the other side via an intermediate state.

thermal; → hop; → -ing.

thermal inertia
  لختی ِ گرمایی   
laxti-ye garmâyi

Fr.: inertie thermale   

The tendency of a body to resist a change in temperature. A body with a low thermal inertia requires very few calories to change its surface temperature. A low thermal inertia material tends to be thermally insulating, so that the surface temperature changes readily, but those changes are not conducted to depth within the material (Ellis et al., 2007, Planetary Ring Systems, Springer).

thermal; → inertia.

thermal Jeans mass
  جرم ِ جینز ِ گرمایی   
jerme-e Jeans-e garmâyi

Fr.: masse de Jeans thermique   

The → Jeans mass when → turbulence is insignificant.

thermal; → Jeans; → mass.

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