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: 1234
close approach
  نزدش ِ کیپ   
nazdeš-e kip

Fr.: approche serrée   

In astronomy a general term to describe the positions of two or more objects that come unusually near one to another. In particular, regarding an asteroid's position with respect to Earth, when it is within the Moon's orbit.

close; → approach.

close binary star
  ستاره‌ی ِ دورین ِ کیپ   
setâre-ye dorin-e kip

Fr.: étoile binaire serrée   

A binary system in which the separation of the component stars is comparable to their diameters, so that they influence each other's evolution most commonly by the tidal forces.

close; → binary; → star.

close binary system
  راژمان ِ دورین ِ کیپ   
râžmân-e dorin-e kip

Fr.: système binaire serré   

A → binary system in which the distance separating the stars is comparable to their size. Most close binaries are spectroscopic binaries (→ spectroscopic binary) and/or eclipsing binaries (→ eclipsing binary). In most of them → mass transfer occurs at some stage, an event which profoundly affects the → stellar evolution of the components. The evolution of close binaries depends on the → initial masses of the two stars and their → separation. When the more massive star evolves into a → red giant first, material will spill through the inner point onto its companion, thereby affecting its companion's evolution. Mass transfer can also alter the separation and → orbital period of the binary star.

close; → binary; → system.

close encounter
  رویارویی ِ کیپ   
ruyâruyi-ye kip

Fr.: rencontre proche   

1) In a → star cluster, coming across of two stars so closely that their → orbits alter by their mutual → gravitational attractions.
2) As regards an → asteroid or → comet, a situation when it crosses the Moon's orbit and approaches the Earth with a risk of collision. See also → close approach, → encounter.

close; → encounter.

closed
  بسته   
basté (#)

Fr.: fermé   

Having boundaries; limited. → closed curve; → closed Universe.

Closed, p.p. of close, from M.E. clos, from O.Fr., from clore "to shut," from L. clausus, p.p. of claudere "to close."

Basté p.p.of bastan, 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, → band.

closed curve
  خم ِ بسته   
xam-e basté (#)

Fr.: courbe fermée   

A curve whose ends are joined.

closed; → curve.

closed space
  فضایِ بسته   
fazâ-ye basté (#)

Fr.: espace fermé   

A bounded space the surface of which has the property that if one travels in any direction upon it without changing direction, one will end up back to the departure point. An example is a sphere. Triangles which lie on the surface of a closed space will have a sum of angles which is greater than 180°. An closed space has a positive → curvature. See also → closed Universe, → open space.

closed; → space.

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."

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