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

For a given component in a → gas mixture, the change in → Gibbs free energy (G) with respect to change in amount of the component (n), when pressure, temperature, and amounts of other components remain constant: ∂G/∂n. Components are in equilibrium if their chemical potentials are equal.

→ chemical; → potential.

The amount of → work required to move a unit → electric charge from → infinity to a specific point against an → electric field. The → SI unit of electric potential is → joules per → coulomb, otherwise known as → volt.

→ electric; → potential.

A potential φ defined so that the → electric field  E is expressed by a combination of its → gradient and the variation of the → magnetic vector potential over time: E = -∇φ -∂A/∂t.

→ electric; → scalar; → potential.

The combination of both → electric scalar potential and → magnetic vector potential.

→ electromagnetic; → potential.

An imaginary surface surrounding a body, or group of bodies, over which the gravitational field is of constant strength and, at all points, is directed perpendicular to the surface. For a single star the surface is spherical. In a close binary system the equipotential surface of the components interact to become hourglass-shaped. → Roche lobe; → Lagrangian points.

From → equi-; → potential; → surface.

In quantum mechanics, the energy that is necessary to change a system from a → ground state to a given → excited state; also called excitation energy.

→ excitation; → potential.

1) The energy that an object possesses because of its position in a → gravitational field, especially an object near the surface of the Earth where the → gravitational acceleration can be assumed to be constant, at about 9.8 m s^-2.
2) In a two body system. It is the amount of work done in bringing the mass m to the distance R from M: E_P = -GMm/R, where G is the → gravitational constant.
3) For a uniform sphere. It is E_P = -(3/5)GM²/R, where G is the gravitational constant and M is the mass contained in the sphere of radius R.

→ gravitational; → potential; → energy.

The energy required to remove an electron from an isolated atom or molecule. The ionization potential for hydrogen is 13.6 eV, which corresponds to an ultraviolet ionizing photon with a wavelength of 912 A. Also called → ionization energy.

→ ionization; → potential.

Same as → Lagrangian function.

→ kinetic; → potential.

An important quantity in the characterization of → gravitational lensing. The lensing potential is obtained by projecting the three-dimensional Newtonian potential on the lens plane and by properly re-scaling it. It is a two-dimensional analog to the → gravitational potential.

→ lensing; → potential.

A vector field A defined so that the → magnetic field  B is given by its → curl: B = ∇ x A.

→ magnetic; → vector; → potential.

A potential in a field of force obeying the inverse-square law such as → gravitational potential.

→ Newtonian; → potential.

1) A latent ability that may or may not be developed; possibility.
2) Physics: The → work required to → move a unit positive → charge, unit magnetic pole, or an amount of → mass respectively from → infinity (i.e. a place infinitely distant from the causes of the field) to a designated point. Gravitational potential is always negative, but the electric or magnetic potentials may be positive or negative.
3) (adj.) Capable of being or becoming, as opposed to → actual.
See also:
→ chemical potential, → electric scalar potential, → electromagnetic potential, → equipotential surface, → excitation potential, → gravitational potential energy, → ionization potential, → kinetic potential, → magnetic vector potential, → potential barrier, → potential density, → potential difference, → potential energy, → potential energy curve, → potential field, → potential gradient, → potential well, → potentiality, → retarded potential, → scalar potential, → thermodynamic potential, → Yukawa potential.

From L.L. potentialis "potential," from L. potentia "power," potis "powerful, able, capable;" cognate with Av. paiti- "lord, husband;" Mod.Pers. -bad (sepah-bad "general, commander of an army"); Skt. páti- "master, husband;" Gk. posis "husband;" Lith. patis "husband."

Tavand, from tav- + -vand. The first component tav- is the stem of tavân "power, strength," tavânestan "to be powerful, able;" variants tâv, tâb, (dialects) tew "power;" Mid.Pers. tuwan "power, might;" O.Pers. tav- "to have power, to be strong, to be able," tauman- "power, strength," tunuvant- "powerful;" Av. tauu- (tu-) "to be able, strong," tavah- "power," təviši- "strength" (Mod.Pers. tuš "power, ability"); Skt. tavⁱ- "to be strong, to have authority," tavas-, tavisa- "strong, energetic," tavisi- "power, strength;" Gk. taus, saos "healthy;" L. tumere "to be swollen;" PIE *teu- "to swell, be strong." The second component -vand a suffix of adjectives and agent nouns, → actual.
Note: Tavand used as both noun and adjective, such as honarmand (n.) and mard-e honarmand (adj.).

Region in a field of force in which the potential is such that a particle, which is subject to the field, encounters opposition to its passage.

→ potential; → barrier.

Of a fluid parcel at pressure P, the density that it would acquire if adiabatically brought to a reference pressure.

→ potential; → density.

Between two points, the work done in taking the unit test object from one point to the other. Potential is a scalar quantity.

→ potential; → difference.

Of a system, the work done in changing the system from some standard configuration to its present state. Thus, if a body of mass m is raised vertically through a height h, the work done, mgh, is the increase in potential energy.

→ potential; → energy.

A plot that displays the → potential energy of a moving body as a function of its position. It is explained by the → conservation of energy and the conversion of potential energy into → kinetic energy and vice versa.

→ potential; → energy; → curve.

A field that has a → potential. A continuous → vector fieldA in a domain D is a potential field in D if and only if its → work around every closed curve C contained in D is zero: ∫A.ds = 0. Examples include the → gravitational field and the → electrostatic field.

→ potential; → field.

At a point, the rate of change of potential V, with distance x, measured in the direction in which the variation is a maximum. The intensity F of the field is proportional to the potential gradient, but is oppositely directed: F = -dV/dx.

→ potential; → gradient.