An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 48 Search : principle
Mach's principle
  پروز ِ ماخ   
parvaz-e Mach

Fr.: principe de Mach   

The local → inertial frame and the → inertia of any body results from the distribution of all matter in the Universe. This principle has been neither confirmed nor refuted.

Mach number; → number.

Newtonian principle of relativity
  پروز ِ بازانیگی ِ نیوتن   
parvaz-e bâzânigi-ye Newton

Fr.: principe de relativité de Newton   

The Newton's equations of motion, if they hold in any → reference frame, they are valid also in any other reference frame moving with uniform velocity relative to the first.

Newtonian; → principle; → relativity.

Pauli exclusion principle
  پروز ِ سکلان ِ پاؤلی   
parvaz-e sokolân-e Pauli

Fr.: principe d'exclusion de Pauli   

A quantum mechanical principle according to which no two identical → fermions can share the same → quantum state. Also known as → exclusion principle.

In honor of Wolfgang Pauli (1900-1958), Austrian theoretical physicist, who formulated the principle in 1925; → exclusion; → principle.

perfect cosmological principle
  پروز ِ کیهان‌شناسیک ِ فرساخت   
parvaz-e keyhânšenâsik-e farsâxt

Fr.: principe cosmologique parfait   

The → assumption, adopted by the → steady-state theory, that all observers, everywhere at all times, would view the same large-scale distribution of matter in the → Universe in all regions and in every direction. In contrast to the → cosmological principle, the perfect cosmological principle adds the assumption that the Universe does not change with time on the large scale.

perfect; → cosmological; → principle.

parvaz (#)

Fr.: principe   

A fundamental, primary assumption, or general law from which others are derived.

From M.E., from O.Fr. principe, from L. principium "a beginning, first part," from princeps "first, chief, prince," literally "that takes first," from primus "first" + root of capere "to take."

Parvaz "origin, root, stock" (as used in particular by Ferdowsi); cf. Av. fra-vāza- "drawing from; leading onward," from Av. fra-, frā- "before; forward, forth" (fratəma- "first, front," pouruua- "first," fra-cara- "preceding;" O.Pers. fra- "forward, forth;" Mid.Pers. fra-; cf. Skt. pra- "before, formerly," prathama- "earliest, initial," pūrva- "first;" Gk. pro; L. pro; O.E. fyrst "foremost," superlative of fore) + vaz- "to draw, guide; bring; possess; fly; float," vazaiti "guides, leads" (cf. Skt. vah- "to carry, drive, convey," vahati "carries," pravaha- "bearing along, carrying," pravāha- "running water, stream, river;" L. vehere "to carry;" O.E. wegan "to carry;" O.N. vegr; O.H.G. weg "way," wegan "to move," wagan "cart;" M.Du. wagen "wagon;" PIE base *wegh- "to drive;" see also → flight).

principle of action and reaction
  پَروز ِ ژیرش و واژیرش، ~ کنش و واکنش   
parvaz-e žireš va vâžireš, ~ koneš va vâkoneš

Fr.: principe d'action et de réaction   

Newton's third law of motion, which states that for every action there must be an equal and opposite reaction.

principle; → action; → reaction.

principle of constancy
  پروز ِ پایایی ِ تندی ِ نور   
parvaz-e pâyâyi tondi-ye nur

Fr.: principe de la constance de la vitesse de la lumière   

The second postulate in Einstein's theory of → special relativity whereby the → velocity of light in → vacuum has the same absolute value in all → inertial reference frames irrespective of the direction and speed of propagation of the light source. It should be emphasized that this constancy of the speed of light holds among → reference frames moving uniformly with respect to each other. An observer accelerated with respect to a light source will measure a speed of light that is smaller than the speed of light measured in a → rest frame. See also → principle of relativity.

principle; constancy, noun related to → constant.

principle of covariance
  پَروز ِ هم‌ورتایی   
parvaz-e hamvartâyi

Fr.: principe de covariance   

In special relativity, the principle that the laws of physics take the same mathematical form in all inertial frames of reference.

principle; → covariance.

principle of equivalence
  پَروز ِ هموگ‌ارزی   
parvaz-e hamug-arzi

Fr.: principe d'équivalence   

In → general relativity the principle which states that in the immediate proximity of an → accelerating system the acceleration is physically equivalent to → gravitational force. This principle also implies the equivalence of → gravitational mass and → inertial mass. Same as the → equivalence principle. See also → Einstein's elevator.

principle; → equivalence.

principle of excluded middle
  پروز ِ میانی سکلانده   
parvaz-e miyâni sokalândé

Fr.: principe du milieu exclu, ~ ~ tiers ~   

The second principle of → formal logic introduced in Aristotle's theory of the → syllogism: A statement is either → true or → false. In other words, two → contradictory → propositions cannot both be true. The truth of one implies the falsehood of the other. Also called law of excluded middle and → principle of excluded third.

principle; → exclude; → middle.

principle of excluded third
  پروز ِ سومی سکلانده   
parvaz-e sevomi sokalândé

Fr.: principe du tiers exclu   

Same as → principle of excluded middle.

principle; → exclude; → third.

principle of identity
  پروز ِ ایدانی   
parvaz-e idâni

Fr.: principe d'identité   

The first principle of → formal logic introduced in Aristotle's theory of the → syllogism: If a statement is true then it is true. Also called → law of identity.

principle; → identity.

principle of least action
  پَروز ِ کمترین ژیرش، ~ ~ کنش   
parvaz-e kamtarin žireš, ~ ~ koneš

Fr.: principe de moindre action   

The principle that, for a system whose total mechanical energy is conserved, the path to be taken for the system from one configuration to another is the one whose action has the least value relative to all other possible paths and from the same configurations. Also called Maupertuis' principle, least-action principle.

principle; → least; → action.

principle of non-contradiction
  پروز ِ ناپادگویی   
parvaz-e nâpâdguyi

Fr.: principe de non-contradiction   

The third principle of → formal logic introduced in Aristotle's theory of the → syllogism: No statement can be both → true and → false at the same time. Also called → law of non-contradiction.

principle; → non-; → contradiction.

principle of relativistic causality
  پروز ِ بنارمندی ِ باز‌آنیگی‌مند   
parvaz-e bonârmandi-ye bâzânigi-mand

Fr.: principe de la causalité relativiste   

One consequence of the theory of → special relativity, according to which no two events separated by a distance greater than their separation in time multiplied by the → speed of light may have a → causal influence on each other. Violation of this principle leads to → paradoxes, such as that of an → effect preceding its → cause.

principle; → relativistic; → causality.

principle of relativity
  پروز ِ بازانیگی   
parvaz-e bâzânigi

Fr.: principe de relativité   

The first postulate in Einstein's theory of → special relativity whereby all the laws of physics are the same in every → inertial reference frame. In other words, no physical measurement can distinguish one inertial reference frame from another. See also → principle of constancy.

principle; → relativity.

relativity principle
  پروز ِ بازانیگی   
parvaz-e bâzânigi

Fr.: principe de relativité   

The requirement employed by Einstein in his relativity theories, that the equations describing the laws of physics are the same in all frames of reference. This statement and that of the constancy of the speed of light constitute the founding principles of special relativity.

Relativity; → principle.

Ritz combination principle
  پروز ِ میازش ِ ریتز   
parvaz-e miyâzeš-e Ritz

Fr.: principe de combinaison de Ritz   

An empirical rule discovered before the advent of quantum mechanics which states that it is possible to find pairs of spectral lines, which have the property that the sum of their wavenumbers is also an observed spectral line.

Named after Walther Ritz (1878-1909), a Swiss theoretical physicist; → combination; → principle.

strong anthropic principle
  پروز ِ انسان-هستی ِ سترگ   
parvaz-e ensân-hasti-ye sotorg

Fr.: principe anthropique fort   

A version of the → anthropic principle that claims that the → Universe must be suitable for the formation of → intelligent life at some point. Compared with the → weak anthropic principle, this version is very controversial. Its implications are highly speculative from a scientific viewpoint.

strong; → anthropic; → principle.

superposition principle
  پروز ِ برهم‌نهش   
parvaz-e barhamneheš

Fr.: principe de superposition   

1) Math.: The principle concerned with homogeneous and non-homogeneous → linear differential equations, stating that two or more solutions to a linear equation or set of linear equations can be added together so that their sum is also a solution.
2) One of the most fundamental principles of → quantum mechanics which distinctly marks the departure from classical concepts. It holds that any linear superposition of → wave functions is also a possible wave function. Simply put, the state of an object is all its possible states simultaneously, as long as we do not look to check. It is the measurement itself that causes the object to be limited to a single possibility. The superposition principle is rooted in the linearity of → Schrödinger's equation. Hence if two solutions of the wave function, ψ1 and ψ2, are known, other solutions, of the form: ψ = a1ψ1 + a2ψ2 also represent possible states of the system.

superposition; → principle.

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