An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1223
coherent scattering
  پراکنش ِ همدوس   
parâkaneš-e hamdus

Fr.: diffusion cohérente   

A scattering process in which the scattered radiation bears the same frequency and phase as the incident radiation.

coherent; → scattering.

coherent source
  خن ِ همدوس   
xan-e hamdus

Fr.: source cohérente   

One of two light beams derived from the same source in → interference experiments. It is impossible to obtain interference from two separate sources because their → wavefronts do not have a constant → phase difference. In → Young's experiment, → Fresnel's biprism, → Fresnel's mirrors, and → Lloyd's mirror the two sources always have a point-to-point correspondence of phase, since they are both derived from the same source.

coherent; → source.

cohesion
  همدوسش   
hamduseš (#)

Fr.: cohésion   

Holding together.
Physics: The attraction between the molecules of a solid or liquid that holds the parts of the substance together.

From L. cohæsus, p.p. of cohærere "to stick together," → coherence.

Hamduseš, verbal noun from hamdusidan "to cohere," → coherence.

cohesive
  همدوسنده، همدوسشی   
hamdusandé, hamduseši

Fr.: cohésif   

1) Of or pertaining to the molecular force → cohesion.
2) Characterized by or causing → cohesion.

Adjective from → cohere.

cohesive energy
  کاروژ ِ همدوسش   
kâruž-e hamduseš

Fr.: énergie de cohésion   

The energy associated with the chemical bonding of atoms in a solid.

cohesive; → energy.

cohesive force
  نیروی ِ همدوسش   
niru-ye hamduseš

Fr.: force cohésive, ~ de cohésion   

The force of → attraction between the molecules of the same substance.

cohesive; → force.

coil
  پیچه   
picé (#)

Fr.: bobine   

A device consisting of a length of electrical wire wound in a spiral to provide magnetic field by → electromagnetic induction.

Maybe from M.E. cull, from M.Fr. culier, coillir "to gather," from L. colligere "to bind together," → collect.

Picé "a curled, a twisted figure or object," from picidan "to twist, invove, enttwine, coil."

coincide
  برهم‌افتادن، هم‌افتادن   
barhamoftâdan, hamoftâdan

Fr.: coïncider   

1) (Of two more objects) to correspond in area and outline; to occupy the same place.
2) To happen at the same time.

Coincide, from Fr. coincider, from M.L. coincidere, from L. → co- "together" + incidere "to fall upon," from in- "upon" + cadere "to fall," PIE base *kad- "to fall".

Barhamoftâdan, from bar- "to, upon, together" + oftâdan "to fall," Mid.Pers. patet "falls," opastan "to fall," Av. pat- " to fly, fall, rush," cf. Skt. patati "he flies, falls," L. petere "to fall, rush out," Gk. piptein "to fall," petomai "I fly," PIE base *pet- "to fly, to rush."

coincidence
  برهم‌افت، هم‌افت، هم‌افتاد   
barhamoft, hamoft, hamoftâd

Fr.: coïncidence   

1) Fact, event, or condition of coinciding.
2) The occurrence of events simultaneously in a striking manner but without any causal connexion between them.

coincide.

coincident
  برهم‌افتان، هم‌افتان   
barhamoftân

Fr.: coïncident   

Occupying the same area in space or happening at the same time. Of two geometric figures, matching point for point.

From Fr. coincident, from M.L. coincident-, coincidens, pr.p. of coincidere, → coincide.

coincide.

colatitude
  هم‌وَرونا   
ham-varunâ

Fr.: colatitude   

The polar angle on a sphere measured from the north pole instead of the equator; equal to "90° - latitude".

co- + → latitude.

cold
  سرد   
sard (#)

Fr.: froid   

Having a relatively low temperature.

M.E., from O.E. cald, ceald "cold, cool" (cf. O.Fr. and O.Sax. kald, O.H.G. and Ger. kalt, Goth. kalds "cold"), from PIE root *gel-/*gol- "cold;" cf. L. gelare "to freeze," gelu "frost," glacies "ice;" Kurd. girsân, girsiân "to coagulate" (Cheung 2007).

Sard "cold, cool," afsordan, afsârdan "to congeal;" Mid.Pers. sard/sart "cold;" Av. sarəta- "cold;" cf. Skt. śiśira- "cold;" L. calidus "warm;" Lith. šaltas "cold;" Welsh clyd "warm;" PIE *keltos- "cool."

cold absorber
  درشمگر ِ سرد   
daršamgar-e sard

Fr.: absorbeur froid   

A broad → absorption feature observed in → X-ray spectra of → active galactic nuclei (AGN). It is caused by material associated with the → interstellar medium in our → Galaxy and/or the host galaxy of the AGN or cold material near the AGN. → Quasars commonly have their X-ray spectrum absorbed by cold gas between us and the quasar X-ray source (along our → line of sight). This is particularly common in less luminous quasars. See also → warm absorber.

cold; → absorber.

cold accretion flow
  تچان ِ فربال ِ سرد   
tacân-e farbâl-e sard

Fr.: écoulement d'accrétion froid   

1) A type of → accretion flow by a → compact object such as a → black hole that consists of cool → optically thick gas and has a relatively high mass → accretion rate, in contrast to → hot accretion flows.
2) Gas accreting from the → intergalactic medium (IGM) onto → galactic haloes with sufficiently low velocities so that it will not be shocked to the → virial temperature of the halo, but will instead flow at a relatively low temperature (T ~ 104 K). Galaxies grow by accreting gas from → cosmic filaments. Feedback from star formation and → active galactic nuclei returns a significant fraction of the → interstellar medium (ISM) to the halo and may even blow it out of the halo into the IGM. This "cold accretion" will happen if the cooling time of → virialized gas is too short to maintain a hot, → hydrostatic halo. The existence of such a cold accretion mode has been confirmed by simulations, which have furthermore demonstrated that cold mode accretion can also be important for halos sufficiently massive to contain hot, hydrostatic gas. Because gas accretes preferentially along the filaments of the cosmic web, the streams of infalling gas have relatively high gas densities and correspondingly low cooling times. This allows the cold streams to penetrate the hot, hydrostatic halos surrounding massive galaxies, particularly at → high redshifts (F. van de Voort et al., 2012, MNRAS 421, 2809).

cold; → accretion; → flow.

cold dark matter (CDM)
  ماده‌ی ِ سرد ِ تاریک   
mâdde-ye sard-e târik (#)

Fr.: matière noire froide   

Any → hypothetical → non-baryonic  → dark matter that is → non-relativistic at the point of → decoupling in the → early Universe. CDM plays a key role in → cosmic structure formation. See also → CDM model, → lambda cold dark matter, → Meszaros effect, → missing satellites problem.

cold; → dark; → matter.

cold disk accretion
  گرده‌ی ِ فربال ِ سرد   
gerde-ye farbâl-e sard

Fr.: disque d'accrétion froid   

An accretion process whereby material coming from an → accretion disk settles onto the → protostellar surface through a geometrically thin layer or thin accretion columns. Heat brought into the protostar in the accretion flow radiates freely into space until the temperature attains the photospheric value. Most of the stellar surface is unaffected by the accretion flow (see, e.g., Hosokawa et al. 2010, ApJ 721, 478).

cold; → disk; → accretion.

collaboration
  همکاری   
hamkâri (#)

Fr.: collaboration   

The act or process of working with another or others on a joint project.

From Fr. collaboration, noun of action from L. collaborare from → com- "with" + labore "to work."

Hamkâri, from ham-, → com-, + kâr, → work, + -i verbal noun suffix.

collapsar
  رمب‌اختر   
rombaxtar

Fr.: collapsar   

The collapse of the core of a very massive star which results in a black hole accompanied by a very energetic → gamma-ray burst.

From collaps(e) + (st)ar.

collapse
  ۱) رمبیدن؛ ۲) رمبش   
1) rombidan (#); 2) rombeš (#)

Fr.: 1) s'effondrer; 2) effondrement   

1) (v.) To fall inward abruptly under its own → gravity.
2) (n.) The act of falling inward abruptly under its own gravity. → gravitational collapse; → core collapse.

From L. collapsus, p.p. of collabi "fall together," from → com- "together" + labi "to fall, slip."

1) Mod.Pers. rombidan "to fall apart, to crumble," Hamadâni, Malâyeri: rommidan, Lori remese "get destroyed," remane "to destroy a building," possibly cognate with E. crumble "to break into small fragments," from O.E. cruma, akin to D. kruim, Ger. Krume "crumb," L. grumus "heap of earth," root of Fr. grumeau "lump."
2) Rombeš from present stem romb "collapse" + noun suffix -eš.

collapse of the wave function
  رمبش ِ کریای ِ موج   
rombeš-e karyâ-ye mowj

Fr.: effondrement de la fonction d'onde   

The idea, central to the → Copenhagen Interpretation of quantum theory, whereby at the moment of observation the → wave function changes irreversibly from a description of all of the possibilities that could be observed to a description of only the event that is observed. More specifically, quantum entities such as electrons exist as waves until they are observed, then "collapse" into point-like particles. According to the Copenhagen Interpretation, observation causes the wave function to collapse. However it is not known what causes the wave function to collapse. Same as → wave collapse.

collapse; → wave function.

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