An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 27 Search : dynamics

Fr.: aérodynamique   

The science that is concerned with the study of the → motion of → air and other gaseous → fluids and with the → forces acting on bodies moving through such fluids.

Aerodynamics, from Gk. aero-, → air, + → dynamics.


Fr.: astrodynamique   

The science dealing with the motion of satellites, rockets, and spacecrafts. It uses the principles of celestial mechanics.

Astrodynamics, from → astro- "star" + → dynamics.

Axtartavânik, from axtar, → astro-, + tavânik, → dynamics.

  رنگ توانیک   

Fr.: chromodynamique   

A → quantum field theory of the → interaction of → quarks possessing a distinctive property called → color, in which the quarks exchange → gluons in a manner that is analogous to the interaction of → charged particles in → electrodynamics.

chromo-; → dynamics.


Fr.: dynamique   

The branch of → mechanics that explains how particles and systems move under the influence of forces.

dynamic; → -ics.


Fr.: électrodynamique   

The phenomena, science, and applications of moving electric charges, as contrasted with → electrostatics. More specifically, the branch of physics concerned with the → interaction of → electric currents with → magnetic fields and → electric fields or with other electric currents.

electro- + → dynamics.

first law of thermodynamics
  قانون ِ نخست ِ گرماتوانیک   
qânun-e naxost-e garâtavânik

Fr.: première loi de la thermodynamique   

The total energy of a → closed system is constant. This means that energy can be changed from one form to another, or transferred from one system to another, but it cannot be created or destroyed. A mathematical formulation of the first law is: δQ = δU + δW, where δQ is the heat transferred to the system, δU the change in internal energy (resulting in a rise or fall of temperature), and δW is the work done by the system.

first; → law; → thermodynamics.

fluid dynamics
  توانیک ِ شاره‌ها   
tavânik-e šârehâ

Fr.: dynamique des fluides   

The branch of → fluid mechanics that deals with the movement of gases and liquids.

fluid; → dynamics.

galactic dynamics
  دینامیک ِ کهکشانی   
tavânik-e kakhešâni

Fr.: dynamique galactique   

The study of the → motions of the → stars, → gas, and → dark matter in a → galaxy to explain the main → morphological and → kinematical features of the galaxy.

galactic; → dynamics.

Hamiltonian dynamics
  توانیک ِ هامیلتون   
tavânik-e Hamilton

Fr.: dynamique hamiltonienne   

The study of → dynamical systems in terms of the → Hamilton's equations.

Hamiltonian function; → dynamics.


Fr.: hydrodynamique   

The branch of physics dealing with the motion, energy, and pressure of neutral → fluids.

hydro- + → dynamics.

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

Fr.: magnétohydrodynamique idéale   

Magnetohydrodynamics of a → plasma with very large (infinite) → conductivity. In this condition, → Ohm's law reduces to E = -v × B, where E represents → electric field, B → magnetic field, and v the → fluid velocity. Ideal MHD is the simplest model to describe the dynamics of plasmas immersed in a magnetic field. It is concerned with → one-fluid magnetohydrodynamics and neglects → resistivity. This theory treats the plasma composed of many charged particles with locally neutral charge as a continuous single → fluid. Ideal MHD does not provide information on the velocity distribution and neglects the physics relating to wave-particle interactions, as does the two-fluid theory as well. It does have the advantage that the macroscopic dynamics of the → magnetized plasma can be analyzed in realistic three-dimensional geometries (K. Nishikawa & M. Wakatani, 2000, Plasma Physics, Springer). See also → non-ideal magnetohydrodynamics.

ideal; → magnetohydrodynamics.

Lagrangian dynamics
  توانیک ِ لاگرانژی   
tavânik-e lâgrânži

Fr.: dynamique lagrangienne   

A reformulation of → Newtonian mechanics in which dynamical properties of the system are described in terms of generalized variables. In this approach the → generalized coordinates and → generalized velocities are treated as independent variables. Indeed applying Newton's laws to complicated problems can become a difficult task, especially if a description of the motion is needed for systems that either move in a complicated manner, or other coordinates than → Cartesian coordinates are used, or even for systems that involve several objects. Lagrangian dynamics encompasses Newton dynamics, and moreover leads to the concept of the → Hamiltonian of the system and a process by means of which it can be calculated. The Hamiltonian is a cornerstone in the field of → quantum mechanics.

Lagrangian; → dynamics.

laws of dynamics
  قانون‌های ِ توانیک   
qânunhâ-ye tavânik

Fr.: lois de dynamique   

The three basic laws of → dynamics which were first formulated by Isaac Newton in his classical work "Mathematical Principles of Natural Philosophy" published in 1687. → Newton's first law of motion; → Newton's second law of motion; → Newton's third law of motion.

law; → dynamics.

magnetohydrodynamics (MHD)

Fr.: magnétohydrodynamique   

The dynamics of an ionized plasma in the non-relativistic, collisional case. In this description, charge oscillations and high frequency electromagnetic waves are neglected. It is an important field of astrophysics since plasma is one of the commonest forms of matter in the Universe, occurring in stars, planetary magnetospheres, and interplanetary and interstellar space.

From → magneto- + → hydrodynamics.

MOdified Newtonian Dynamics (MOND)
  توانیک ِ نیوتنی ِ واترزیده   
tavânik-e niyutoni-ye vâtarzidé

Fr.: dynamique newtonienne modifiée   

A modification of the Newton's law of gravitation below a critical acceleration of about 1.2 x 10-8 cm s-2, where the gravitational force scales as 1/r instead of 1/r2. Originally put forward to describe the rotation curves of galaxies with no need to assume any dark matter, MOND is now tested at larger cosmological scales (Milgrom, M. 1983, ApJ, 270, 365).

modify; → Newtonian dynamics.

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.

nonlinear dynamics
  توانیک ِ ناخطی   
tavânik-e nâxatti

Fr.: dynamique non-linéaire   

Same as → chaos.

nonlinear; → dynamics.

one-fluid magnetohydrodynamics
  مغنات-و-هیدروتوانیک ِ تک-شاره   
meqnâtohidrotavânik-e tak-šâre

Fr.: magnétohydrodynamique à une fluide   

A → magnetohydrodynamics treatment in which the → plasma consists only of one particle species and moves with the bulk speed. The thermal motion of the particles is neglected and thus there is no motion of particles relative to each other.

one; → fluid; → magnetohydrodynamics.

quantum chromodynamics
  رنگ-توانیک ِ کو‌آنتومی   
rangtavânik-e kuântomi

Fr.: chromodynamique quantique   

The → quantum field theory that deals with the → strong interaction and the structure of elementary particles in the framework of → quantum theory. The cohesive attraction between the → quarks, that constitute → hadrons, involves the participation of three particles. Each of these particles is assigned a different → color "charge." The existence of these "charges" requires a multiplicity of different messenger particles to communicate the interaction and glue the quarks together. These messengers are called → gluons and there are eight different types.

quantum; → chromodynamics

quantum electrodynamics (QED)
  برقاتوانیک ِ کو‌آنتومی   
barqâtavânik-e kuântomi

Fr.: électrodynamique quantique   

The → quantum field theory that describes the properties of → electromagnetic radiation and its interaction with electrically charged matter in the framework of → quantum theory.

quantum; → electrodynamics.

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