An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 360
near-Earth object (NEO)
  بر‌آخت ِ زمین-نزدیک   
barâxt-e zamin-nazdik

Fr.: géocroiseur   

An → asteroid, → comet, or large → meteoroid whose orbit brings it exceptionally close to the Earth, and which may therefore pose a collision danger. Most such objects are in orbits around the Sun with → perihelion distance less than 1.3 → astronomical units. See also → near-Earth asteroid.

near; → earth; → object.

  فروسرخ ِ نزدیک   
forusorx-e nazdik (#)

Fr.: proche infrarouge   

That region of the → electromagnetic spectrum covering shorter infrared wavelengths. It contains the → infrared windows between about 0.8 and 8 → microns, but the longer wavelength limit is not well defined. See also: → infrared radiation, → mid-infrared, → far-infrared, → submillimeter radiation.

near; → infrared.

miq (#)

Fr.: nébuleuse   

1) A cloud of gas and dust in the interstellar space. There are three general types: → emission nebulae, → reflection nebulae, and → dark nebulae.
2) A celestial body appearing nebulous or fuzzy when seen with the telescope. Formerly, galaxies, which appeared nebular but are constituted of billions of stars, were not distinguished from truly nebular objects, made of gas and dust.

From L. nebula "mist," nimbus "rainstorm, rain cloud;" cognate with Av. napta- "moist," nabās-câ- "cloud," nabah- "sky;" Pers. nam "moisture;" cf. Gk. nephos "cloud, mass of clouds," nephele "cloud;" Skt. nábhas- "moisture, cloud, mist;" O.H.G. nebul; Ger. Nebel "fog;" O.E. nifol "dark;" PIE base *nebh- "cloud, vapor, fog, moist, sky."

Miq "nebula" (used by Tusi, in Pers. translation of Sufi's "Book of Fixed Stars"), variants meh "fog," mož, Tabari miyâ, Lori/Laki (kara) mozy, Ossetic mig/megæ, from Mid.Pers. mēq "cloud, mist;" Av. mēγa- "cloud;" cf. Skt. meghá- "cloud, overcast weather;" Gk. omikhle "mist;" Lith. miglà "mist, haze;" PIE base *mighlā- "cloud."


Fr.: nébulaire   

Of or relating to or resembling a → nebula.

nebula + → -ar.

nebular continuum
  پیوستار ِ میغی   
peyvastâr-e miqi

Fr.: continuum nébulaire   

The part of a nebular object's → spectrum that is created by → free-free emission.

nebular; → continuum.

nebular hypothesis
  انگاره‌ی ِ میغ   
engâre-ye miq

Fr.: hypothèse nébulaire   

The hypothesis first put forward in the 18-th century that the solar system formed from a primeval nebula around the Sun. Same as the → Kant-Laplace hypothesis.

nebular; → hypothesis.

nebular line
  خط ِ میغی   
xatt-e miqi

Fr.: raie nébulaire   

A → forbidden line that is found in the spectra of → interstellar  → ionized gas. The nebular lines are emitted by several atomic species (e.g. O, O+, O++, N+, S++) and correspond to the → transition from the electronic → metastable state 1D to the → ground state  3P. Examples are the doubly ionized oxygen lines [O III] at 4959 and 5007 Å. See also → auroral line; → transauroral line.

nebular; → line.

nebular variable
  ورتنده‌ی ِ میغی   
vartande-ye miqi

Fr.: variable nébulaire   

A type of eruptive variable star, mainly young FU Orionis and T Tauri types, associated with nebulosity.

nebular; → variable.

nebuliom (#)

Fr.: nébulium   

A hypothetical element, the existence of which was postulated in the nineteenth century to account for unidentified emission lines (e.g. at 3727 and 5007 Å) in the spectra of some luminous nebulae. It was also believed that this element had a small atomic weight. However, the advances of chemistry and physics showed that all the light elements were known and there was no place for this elusive element. Those unidentified lines have now been shown to come from known elements, but they are not usually observable under laboratory conditions. → forbidden lines.

From nebul(a), → nebula, + -ium L. neuter suffix.


Fr.: nébulosité   

1) A nebulous form, shape, or mass.
2) The state or condition of being nebulous.
3) A fuzzy celestial object, constituted of gas and dust, generally part of a larger → nebula.

nebulous; → -ity.


Fr.: nébuleux   

1) Hazy, vague, indistinct, or confused.
2) Cloudy or cloudlike.
3) Of or resembling a nebula or nebulae; nebular (

nebula; → -ous.

bâyesté (#)

Fr.: nécessaire   

1) Being essential or indispensable.
2) Logic, Math.: A condition which must hold for a result to be true, but which does not guarantee it to be true. → if and only if.

M.E. necessaire, from L. necessarius "unavoidable," , from necesse "unavoidable, indispensable," from ne- "not," → un-, + cedere "to withdraw, go away, yield," → precession.

Bâyesté, p.p. of bây-, bâyestan "to be necessary," from Mid.Pers. abây-, abâyistan "to be necessary" (abâyišn "necessity," abâyišnig "necessary"), from Proto-Ir. *upa-aya- "to reach," from upa-, → hypo-, + ay- "to go, to come," → precession.

necessary and sufficient conditions
  بوتارهای ِ بایسته و بسنده   
butârhâ-ye bâyesté o basandé

Fr.: conditions nécessaire et suffisante   

If event A must occur for event B to occur, then it is said that A is → necessary for B. If event A may cause B but there could be some other cause as well, then it is said that A is sufficient to cause B. See also → if and only if (iff).

necessary; → and; → sufficient; → condition.

necessary truth
  راستینی ِ بایسته   
râstini-ye bâyesté

Fr.: vérité nécessaire   

Logic: A → proposition if its → denial is self-contradictory. Also called "logical truth" and "non-contingent truth."

necessary; → truth.

bâyestegi (#)

Fr.: nécessité   

1) The fact of being necessary or indispensable.
2) Something necessary or indispensable.

necessary; → -ity.

suzan (#)

Fr.: aiguille   

A slender pointed piece of metal, usually steel. → magnetic needle.

M.E. nedle, O.E. naeðlæ, nedlæ (cf. O.S. nathla, O.N. nal, O.Fris. nedle, O.H.G. nadala, Ger. Nadel); PIE root *(s)ne- "to sew, to spin;" cf. Skt. snayati "wraps up;" Gk. nein "to spin;" L. nere "to spin."

Suzan, Mid.Pers. sôzan, sucan, related to sok "pointed stick for driving cattle;" Av. sūkā- "needle;" cf. Skt. sūcī- "sting;" L. cuneus "wedge;" PIE base kū- "sharp; spike."

nâyidan (#)

Fr.: nier   

To deny the existence or truth of. To cause to be ineffective or invalid.

From L. negatus p.p. of negare "to say 'no', deny," from Old L. nec "not," from PIE base *ne- "no, not."

Nâyidan infinitive from "no, not," variants na, ni, ma- (prohitive); from Mid.Pers. nê, ma "no, not;" O.Pers. naiy, nai "not;" Av. nôit, naē "not;" cf. Skt. "not;" cf. L. ne-, in-, un-; Gk. ni; Lith. ; O.C.S. ne "not;" PIE *ne-, as above.

nâyeš (#)

Fr.: négation   

1) The act of denying; → denial.
2) The absence or → opposite of something that is actual, positive, or affirmative.
3) A → negative statement, idea, doctrine; a contradiction, refutation, or rebuttal.
4) Logic: If p is a → proposition, then the statement "not p," denoted ¬ p, is the negation or opposite of p. If p is "It is sunny," then ¬ p is "It is not sunny." If p is → true, then ¬ p is → false, and vice versa.

Verbal noun of → negate.

nâyidâr (#)

Fr.: négatif   

1) General: Expressing, containing, or consisting of a negation, refusal, or denial.
2) Math.: Of or relating to a quantity less than zero. Of or relating to the sign (-).
3) Physics: Of or relating to an electric charge of the same sign as that of an electron.
4) Photography: Having dark for light and light for dark.
5) Opposite of → positive.
See also:
negative charge, → negative correlation, → negative crystal, → negative feedback, → negative lens, → negative number, → negative polarization, → negative pressure, → negative skewness.

From O.Fr. negatif (fem. negative), from L. negativus, "denying, inhibiting (legal actions); denied/refused; negative," from negare "to refuse, say 'no'" from Old L. nec "not", from Italic base *nek- "not," from PIE base *ne- "no, not."

Nâyidâr, from nâyidan, → negate, on the model of xaridâr, foruxtâr, xâstâr, virâstâr, etc.

negative charge
  بار ِ ناییدار   
bâr-e nâyidâr

Fr.: charge négative   

An electric charge that has the same sign as the electron.

negative; → charge.

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