An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1353
spectroscopic binary
  دُرین ِ بیناب‌نمایی   
dorin-e binâbnemâyi

Fr.: binaire spectroscopique   

A binary system that cannot be resolved by a telescope, but can be identified by means of the Doppler shift of the spectral lines. As stars revolve, they alternately approach and recede in the line of sight. This motion is shown up in their spectra as a periodic oscillation or doubling of spectral lines.

spectroscopic; → binary.

spectroscopic degeneracy
  واگنی ِ بیناب‌نمایی   
vâgeni-ye binâbnemâyi

Fr.: dégénérescence spectroscopique   

The situation in which spectroscopic features in a certain optical region are not sensitive enough to distinguish adjacent → luminosity classes, for instance → dwarf stars from → giant stars.

spectroscopic; → degeneracy.

spectroscopic mass
  جرم ِ بیناب‌نمایی   
jerm binâbnemâyi

Fr.: masse spectroscopique   

The stellar mass derived from → gravity (g) and radius (R), expressed by M = gR2/G, where G is the → gravitational constant. Spectroscopic mass conveys the actual mass of the star, in contrast with its → initial mass.

spectroscopic; → mass.

spectroscopic parallax
  دیدگشت ِ بیناب‌نمایی   
didgašt-e binâbnamâyi

Fr.: parallaxe spectroscopique   

The measurement of a stellar distance by the absolute magnitude derived from the luminosity criteria of the spectrum and the apparent magnitude of the star.

spectroscopic; → parallax.

spectroscopic variable
  ورتنده‌ی ِ بیناب‌نمایی   
vartande-ye binâbnemâyi

Fr.: variable spectroscopique   

A → variable star that displays changes in its → spectrum. In such stars line intensities may vary and new lines may appear. Examples include → AG Carinae, HD 108, HD 191612, and HD 148937.

spectroscopic; → variable.


Fr.: spectroscopie   

The study of spectral lines from different atoms and molecules. Spectroscopy is an important part of studying the physical and chemical properties of astronomical objects.

Spectro- combining form of → spectrum + → -scopy.

binâb (#)

Fr.: spectre   

The → electromagnetic radiation divided into its constituting wavelengths or frequencies.

From L. spectrum "appearance, image, apparition," from specere "to look at, view;" Gk. skopein "to behold, look, consider," skeptesthai "to look at;" PIE base *spek- "to see;" cf. Av. spas-, spaš- "to attend to; to serve; spy," spasiieiti "looks at, perceives" (Mod.Pers. sepâs "kindness, favor, thanksgiving," sepâsidan "to praise for benefits received);" Skt. paś- "to see, watch," spasati "sees;" L. specere "to look at;" O.H.G. spehônn "to spy," Ger. spähen "to spy."

Binâb "a vision;" Mid.Pers. wênâb "vision," from wên-, present stem of didan "to see;" O.Pers. vain- "to see;" Av. vaēn- "to see;" cf. Skt. veda "I know;" Gk. oida "I know," idein "to see;" L. videre "to see;" PIE base *weid- "to know, to see."

specular reflection
  بازتاب ِ آینه‌وار   
bâztâb-e âyenevâr (#)

Fr.: réflexion spéculaire   

The reflection of light waves in which the reflected waves travel in a definite direction, and the directions of the incident and reflected waves make equal angles with a line perpendicular to the reflecting surface. Same as → regular reflection; opposite of → diffuse reflection.

From L. specularis, from speculum "mirror;" → reflection.

Bâztâb, → reflection; âyenevâr "mirror-like," from âyené, → mirror + -vâr similarity suffix.


Fr.: spéculer   

To guess possible answers to a question when there are not enough information to be certain.

Back formation from O.Fr. speculation, from L. speculatus, p.p. of speculari "to watch over, observe," from specula "watch tower," from specere "to look at, regard," cognate with Av. spas- "to attend; to serve," spasiieiti "looks at, perceives;" Pers. sepâs "kindness, thanksgiving;" Skt. spasati "sees;" Gk. skopein "to behold, look, consider," skeptesthai "to look at;" O.H.G. spehhon "to spy;" Ger. spähen "to spy;" PIE *spek- "to look around, observe."

Gâsidan infinitive from gâs, from Av. kas- "to look at, see," with extension of the vowel and change of the last phoneme from k to g, as in and cognate with negâh (Mid.Pers. nikâh), → look, âgâh (Mid.Pers. âkâh) "aware" (→ Space Situational Awareness), pargast "God forbid!," and maybe (Lori, Laki, Torbat-Heydarie-yi) gâs "perhaps," (Shirâzi, Fasâyi) gâsam "maybe;" cf. Skt. kāś- "to become visible, appear;" Gk. tekmor, tekmar "sign, mark;" PIE base *kwek- "to appear, show."


Fr.: spéculation   

The act or an instance of speculating.

Verbal noun of → speculate.

  ۱) سخن؛ ۲) سخنرانی   
1) soxan (#); 2) soxanrâni (#)

Fr.: 1) parole; 2) discours, allocution   

1) The faculty or power of speaking; oral communication; ability to express one's thoughts and emotions by speech sounds and gesture (
2) A form of communication in spoken language, made by a speaker before an audience for a given purpose (

M.E. speche; O.E. spæc; cf. Dan. sprog, O.S. spraca, O.Fris. spreke, Du. spraak, O.H.G. sprahha, Ger. Sprache "speech."

Soxan "speech, utterance, word;" Mid.Pers. saxwan "word, speech;" O.Pers. θanh- "to declare, say," aθaham "I said;" Av. səngh- "to declare," sənghāmi "I say;" cf. Skt. śams- "to praise, declare;" L. censere "to estimate, think; decide."

tondi (#)

Fr.: vitesse   

The ratio of the distance covered to the time taken by a moving body. Speed in a specified direction is → velocity.

M.E. spede "good luck, prosperity, rapidity;" O.E. sped "success, prosperity, advancement;" cf. O.S. spod "success," Du. spoed "haste, speed," O.H.G. spuot "success," O.H.G. spuoten "to haste;" from PIE base *spe- "to thrive, prosper" (cf. Skt. sphā- "to increase, become fat;" L. sperare "to hope;" O.C.S. spechu "endeavor;" Lith. speju "to have leisure").

Tondi "speed," from tond "swift, rapid, brisk; fierce, severe" (Mid.Pers. tund "sharp, violent;" Sogdian tund "violent;" cf. Skt. tod- "to thrust, give a push," tudáti "he thrusts;" L. tundere "to thrust, to hit" (Fr. percer, E. pierce, ultimately from L. pertusus, from p.p. of pertundere "to thrust or bore through;" PIE base *(s)teud- "to thrust, to beat") + noun suffix -i.

speed of light
  تندی ِ نور   
tondi-ye nur

Fr.: vitesse de la lumière   

Same as → velocity of light.

speed; → light.


Fr.: dépenser   

1) To pay out, disburse, or expend; dispose of (money, wealth, resources, etc.).
2) To employ (labor, thought, words, time, etc.), as on some object or in some proceeding (

M.E. spenden, from O.En. -spendan (in forspendan "use up"), from M.L. spendere, from expendere "to pay out, weigh out money," from → ex- "out" + pendere "to pay, weigh."

Ziyâmidan, from Sogd. zyâm "to consume, spend," ultimately from Proto-Ir. *uz-iam-, from *uz- "out, away," → ex-, + *iam- "to hold, take; stretch, reach out;" cf. Av. yam- "to hold, keep," (+ *apa-) "to take away;" Skt. yam- "to hold, restrain."

  کُره، سپهر   
koré (#), sepehr (#)

Fr.: sphère   

A solid geometric figure generated by the revolution of a semicircle about its diameter; equation: x2 + y2 + z2 = r2.

M.E. spere, from O.Fr. espere, from L. sphæra "globe, ball, celestial sphere," from Gk. sphaira "globe, ball," of unknown origin.

Koré, loan from Ar. kurat.
Sepehr "sphere, celestial globe, heavens, sky;" Mid.Pers. spihr "sphere, sky, firmament, fate;" Av. spiti- in compounds: spiti-dôiθra- "with clear eyes;" Proto-Iranian *spiθra- (in proper name); cf. Skt. śvitrá- "white, whitish."

sphere of influence
  سپهر ِ هنایش   
sepehr-e hanâyeš

Fr.: sphère d'influence   

The region of space around one of the bodies in a system of two celestial bodies where a third body of much smaller mass is influenced by the gravitational field of that body. The sphere of influence of a planet with respect to the Sun has a radius given by: R = RP(MP/MS)2/3, where RP is the radius of the planet's orbit around the Sun, MP is the mass of the planet, and MS is the solar mass. The sphere of influence of the Earth has a radius of about 927,000 km or slightly under 150 Earth radii. Beyond this limit, a space probe will come under the influence of the Sun.

sphere; → influence.

spheres of Eudoxus
  سپهرهای ِ اءودوکسوس   
sepehrhâ-ye Eudoxus

Fr.: sphères d'Eudoxe   

A series of spheres with varying radii centred on the Earth, each rotating uniformly about an axis fixed with respect to the surface of the next larger sphere, all comprising a model in Greek astronomy to describe the motions of the heavenly bodies. The spheres turned with different speeds about axes with different orientations. The fixed stars revolved around the Earth by the motion of the most distant sphere to which the stars were thought to be attached. Each of the five planets' (Mercury, Venus, Mars, Jupiter, and Saturn) motion could be described using four spheres. The Sun and the Moon required three spheres each to explain their motions. Therefore, a total of 27 spheres described the behavior of the heavenly bodies in terms of circular motion. Eudoxus was the first person to devise a model that could explain the → retrograde motion of the planets in the sky along a looped curve known as the → hippopede.

sphere; Eudoxus (Ευδοξοσ) of Cnidus (c 408 BC - c 355 BC), Greek astronomer and mathematician.


Fr.: sphérique   

Having the form of a sphere; of or pertaining to a sphere or spheres.

From → sphere + → -ic + → -al.

spherical aberration
  بیراهش ِ کُره‌ای   
birâheš-e koreyi

Fr.: aberration sphérique, ~ de sphéricité   

An aberration of a spherical lens or spherical mirror in which light rays converge not to a single point but to a series of points with different distances from the lens or mirror. Spherical aberration is corrected by using parabolic reflecting and refracting surface.

spherical; → aberration.

spherical angle
  زاویه‌ی ِ کُره‌ای   
zâviye-ye koreyi

Fr.: angle sphérique   

An angle formed on the surface of a sphere by the intersection of two great circles of the sphere.

spherical; → angle.

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