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: 1223
closed system
  راژمان ِ بسته   
râžmân-e basté

Fr.: système fermé   

Thermodynamics: A system which can exchange energy with the surroundings but not matter. → open system; → isolated system.

closed; → system.

closed Universe
  گیتی ِ بسته   
giti-ye basté (#)

Fr.: Univers fermé   

A → cosmological model, first formulated by Friedmann and Lemaître, in which the Universe has a → finite size and lifetime and → space has a → positive → curvature, e.g. a Universe with a density greater than the → critical density. See also → closed space.

closed; → Universe.

closed wff
   wff بسته   
wff basté

Fr.: FBF fermée   

In → predicate logic, a → wff with no → free occurrences of any → variable. Also called a → sentence.

closed; → wff.

closure
  بندش   
bandeš (#)

Fr.: clôture   

Math.: The property of a set in which the application of a given mathematical operation to any member of the set always has another member of the set as its result.
The intersection of all closed sets that contain a given set.

M.E., from M.Fr., from O.Fr. closure "that which encloses," from L. clausura "lock, fortress, a closing," from p.p. stem of claudere "to close."

Bandeš, verbal noun of bastan "to shut, bind; to clot; to form seed buds," from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie;" Skt. bandh- "to bind, tie, fasten;" PIE *bhendh- "to bind," cf. Ger. binden, E. bind.

closure axiom
  بنداشت ِ بندش   
bondâšt-e bandeš

Fr.: axiome de clôture   

A basic rule in → group theory stating that if a and b are a group element then a * b is also a group element.

closure; → axiom.

closure phase
  فاز ِ بندش   
fâz-e bandeš

Fr.: clôture de phase   

In astronomical interferometry, a method using triplets of telescopes in an array to calculate the phase information and get over the effects of atmospheric turbulence. The method, used in high-resolution astronomical observations, both at radio and at optical wavelengths, allows imaging of complex objects in the presence of severe aberrations.

closure; → phase.

clothoid
  کلوتویءید   
klotoid

Fr.: clothoïde   

A plane curve of spiral form, → Cornu's spiral.

From Gk. kloth, from klothein "to spin" + epenthetic vowel -o- + eides "form," → -oid; because the curve is reminiscent of the thread that winds around a weaving loom. → Klotho.

cloud
  ابر   
abr (#)

Fr.: nuage   

1) A visible mass of water droplets and/or ice particles in the atmosphere above the Earth's surface.
2) → interstellar cloud.

Cloud, from O.E. clud "mass of rock," from P.Gmc. *kludas.

Abr, from Mid.Pers. awr, abr (Laki owr, Baluchi haur, Kordi Soriani hewr), Av. awra- "rain cloud, rain," cf. Skt. abhra-"thunder cloud," Gk. afros "scum, foam," L. imber "rain;" also Sk. ambha- "water," Gk. ombros "rain," PIE *mbhros "rain cloud, rain," from *mbh-.

cloud chamber
  اتاقک ِ ابر   
otâqak-e abr

Fr.: chambre à nuage   

An early type of → bubble chamber used for detecting particles of ionizing radiation. It was invented in 1900 by Charles Thomson Rees Wilson (1869-1959), a Scottish physicist, who along with Arthur Compton (1892-1962 ) received the Nobel Prize for physics in 1927.

cloud; → chamber.

cloud cover
  پوشش ِ ابری   
pušeš-e abri (#)

Fr.: couverture nuageuse   

The fraction of the sky covered by clouds. It is expressed in tenths, so that 0.0 indicates a clear sky and 1.0 (or 10/10) indicates a completely covered sky.

cloud; → cover.

cloud fragmentation
  لتپارش ِ ابر   
latpâreš-e abr

Fr.: fragmentation de nuage   

Process by which a → collapsing → giant molecular cloud breaks into dense → clumps, eventually bringing about → pre-stellar cores.

cloud; → fragmentation.

cloudbow
  ابرکمان   
abrkamân

Fr.:   

A large, faintly colored arc formed usually by sunlight falling on a cloud. Also called white rainbow, fogbow, and mistbow. Cloudbow appears white because the water droplets in the cloud or fog are very small compared with those of ordinary rainbows.

cloud; → bow.

cloudburst
  رگبار   
ragbâr (#)

Fr.: averse   

Any sudden and heavy fall of → rain, always of the → shower type.

cloud; → burst.

Ragbâr, from rag + bâr. The second component bâr, variant bârân "rain," from bâridan "to rain." The origin of the first component is not clear. Rag in Persian means "blood vein, vessel," but this sense seems irrelevant here. In Gilaki the bare râk (without bâr) means cloudburst. Râk/rag may be related (via an extinct Iranian parent) to the Skt. stem ri- "to flow, to drop, to become liquid."

cloudiness
  ابر‌آلودگی   
abrâludegi (#)

Fr.: état nuageux, nébulosité   

Same as → cloud cover.

From cloudy, from cloudy, from → cloud + → -ness.

cloudshine
  ابر‌تاب   
abr-tâb

Fr.: éclat de nuage   

Light from nearby stars scattered by → dust grains in low-density outer regions of → molecular clouds. It is seen not only in the → near infrared bands JHK, but also continuously from the visible to 5 μm. Cloudshine could be considered as an intermediate between → scattering in the visible and the → coreshine effect (Foster & Goodman, 2006, ApJ 636, L105). See also

cloud; → shine.

clover
  شبدر   
šabdar (#)

Fr.: trèfle   

Any of various plants of the genus Trifolium with three round, green leaves that are joined together. Clovers occasionally have leaves with four leaflets, instead of the usual three.

M.E. clovere; O.E. clafre; cf. M.L.G. klever, M.Du. claver, Du. klaver, O.S. kle, O.H.G. kleo, Ger. Klee "clover," of uncertain origin.

Šabdar, of unknown origin.

cloverleaf quasar (H1413+117)
  کو‌آسار ِ برگ ِ شبدر   
kuâsâr-e barg-e šabdar

Fr.: quasar du trèfle à quatre feuilles   

A bright → quasar whose image is split into four spots due to → gravitational lensing (Magain et al. 1988, Nature 334, 325). The four images of comparable brightness all lie within 0.7 arc seconds of the image center. The quasar has a → redshift of 2.56, corresponding to a distance of about 11 billion → light-years. Observations indicate that the lensing galaxy is located approximately at the geometrical center of the four images. A firm spectroscopic redshift of the lens has yet to be obtained; however, a → cluster of galaxies at a redshift of z = 1.7 has been suggested to account for the lensing of this system. H1413+117 was the first quasar to be detected in the → submillimeter wave → continuum and in → carbon monoxide emission.

So named because of the optical image; → clover; → leaf; → quasar.

clump
  گوده   
gudé

Fr.: grumeau   

1) A compact mass, in particular that contained in a less dense environment.
2) → molecular clump.

Clump, from Du. klomp "lump, mass," or Low Ger. klump.

Gudé "ball, bowl, tumour" in Gilaki, cf. Skt. guda- "ball, mouthful, lump, tumour," Gk. gloutos "rump," L. glomus "ball," globus "globe," Ger. Kugel, E. clot, PIE *gel- "to make into a ball."

clumped wind
  باد ِ گوده‌دار   
bâd-e gudedâr

Fr.: vent grumelé   

A → radiation-driven wind of → Wolf-Rayet and → O stars, which is not homogeneous, and contains compressions and rarefactions in the form of density clumps. Observationally, wind clumping appears as moving, small-scale structures in spectral line profiles. Indirect indicators of wind clumping include: electron scattering wings of emission lines, too-weak observed UV line profiles, and shapes of X-ray lines. The most likely physical explanation for the presence of these clumps is an instability in radiatively-driven winds. The inclusion of a clumping factor in the models of W-R winds reduces the → mass loss rates by a factor ~ 2-4 relative to homogeneous models. See also → clumping factor.

clumpy; → wind.

clumpiness
  گودگی   
gudegi

Fr.: grumelosité   

Of a → molecular cloud, the property of being made up of → clumps.
The extent with which a molecular cloud is → clumpy.

Clumpiness, from → clumpy + → -ness.

Gudegi from gudé, → clump, + -gi suffix forming noun from adjectives ending in .

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