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: 1059
prime meridian
  نیمروزان ِ نخستی   
nimruzân-e noxosti

Fr.: méridien origine   

The meridian at which longitude is defined to be 0°. The meridian running through Greenwich.

primary; → meridian.

prime number
  عدد ِ نخست   
'adad-e naxost

Fr.: nombre premier   

A number which is divisible by no whole number other than itself and one.

prime; → number.

prime vertical
  هجین ِ نخستی   
hajin-e noxosti

Fr.: premier vertical   

The great circle through the observer's zenith that intersects the horizon at the west and east points. → vertical circle.

primary; → vertical.

primeval atom
  اتم ِ نخستین   
atom-e naxostin

Fr.: atome primitif   

Lemaître's (1931) name for the early dense Universe, which later became known as the → Big Bang theory.

From L. primaevus "early in life," from primus "first," → prime, + aevum "an age," + → -al; → atom.

primordial
  بن‌آغازین   
bonâqâzin

Fr.: primordial   

Pertaining to or existing at or from the very beginning.

From L.L. primordialis "first of all, original," from L. primordium "the beginning," from primus "first" + stem of ordiri "to begin."

Bonâqâzin, from bon "basis; root; foundation; bottom" (Mid.Pers. bun "root; foundation; beginning," Av. būna- "base, depth," cf. Skt. bundha-, budhná- "base, bottom," Pali bunda- "root of tree") + âqâzin "pertaining to the beginning," from âqâz "beginning" (Proto-Iranian *āgāza-, from prefix ā- + *gāz- "to take, receive," cf. Sogdian āγāz "beginning, start," pcγz "reception, taking").

primordial abundance
  فراوانی ِ بن‌آغازین   
farâvâni-ye bonâqâzin

Fr.: abondance primordiale   

The relative amount of a light element (e.g. deuterium, lithium, helium) synthesized in the early Universe.

primordial; → abundance.

primordial black hole
  سیه‌چال ِ بن‌آغازین   
siyahcâl-e bonâqâzin

Fr.: trou noir primordial   

A black hole formed following the Big Bang event due to incredibly violent turbulence that squeezed concentrations of matter to high densities. These black holes, first suggested by Stephen Hawking, are expected to have a mass comparable to that of a mountain and a size as small as an atom. Same as → mini black hole.

primordial; → black hole.

primordial curvature perturbation
  پرتورش ِ خمیدگی ِ بن‌آغازین   
partureš-e xamidegi-ye bonâqâzin

Fr.: perturbation de courbure primordiale   

In cosmological models, the phenomenon that is supposed to seed the → cosmic microwave background anisotropies and the structure formation of the Universe.

primordial; → curvature; → perturbation.

primordial galaxy
  کهکشان ِ بن‌آغازین   
kahkešân-e bonâqâzin

Fr.: galaxie primordiale   

A high redshift, metal-deficient galaxy that formed very early in the history of the Universe.

primordial; → galaxy.

primordial helium
  هلیوم ِ بن‌آغازین   
heliom-e bonâqâzin

Fr.: hélium primordial   

The helium element created in the → early Universe, around 3 minutes after the → Big Bang, when the temperature dropped to 109 degrees; in contrast to the helium being synthesized in stars. Based on observations of helium → emission lines in → H II regions of metal-poor dwarf galaxies (→ metal-deficient galaxy), the primordial 4He → chemical abundance (by mass) is estimated to be YP = 0.24672 ± 0.00017. Moreover, using observations of a near-pristine → intergalactic cloud, a value of 0.250 +0.033-0.025 has been reached (Cooke & Fumagalli, 2018, Nature Astronomy, 2, 657). The theoretical He abundance predicted by → Big Bang nucleosynthesis is 0.24709 ± 0.00017 (Pitrou et al., 2018, arXiv:1801.08023).

primordial; → helium.

primordial nucleosynthesis
  هسته‌هندایش ِ بن‌آغازین   
haste-handâyeš-e bonâqâzin

Fr.: nucléosynthèse primordiale   

The formation of → chemical elements in the → early Universe, between about 0.01 seconds and 3 minutes after the → Big Bang, when the nuclei of primordial matter collided and fused with one another. Most of the → helium in the → Universe was created by this process. Same as → Big Bang nucleosynthesis

primordial; → nucleosynthesis.

principal
  فرین   
farin

Fr.: principal   

First or highest in rank, importance, value, etc. See also → main.

M.E., from O.Fr. principal, from L. principalis "first in importance," from princeps "first, chief, prince," literally "that takes first," from primus "first" + root of capere "to take."

Farin literally "foremost," from far-, Mid.Pers. fra-; O.Pers. fra- "forward, forth;" Av. frā "forth," pouruua- "first;" cf. Skt. pūrva- "first," pra- "before, formerly;" Gk. pro; L. pro; O.E. fyrst "foremost," superlative of fore, E. fore + -in superlative suffix.

principal quantum number
  عدد ِ کو‌آنتومی ِ فرین   
adad-e kuântomi-ye farin

Fr.: nombre quantique principal   

In atomic physics, the first of a set of quantum numbers which describe an atomic orbital. Symbolized as n, it characterizes the size and energy of an orbital.

principal; → quantum; → number.

principle
  پَروَز   
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.

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