An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1259
seziom (#)

Fr.: césium   

A soft ductile chemical element of the → alkali metal group; symbol Cs. It is found in several → silicate minerals, including pollucite. The metal oxidizes in air and reacts violently with water. → Atomic number 55; → atomic weight 132.9054; → melting point 28.4°C; → boiling point 669.3°C; → specific gravity 1.873 at 20°C; and → valence +1. Cesium has several radioactive isotopes, among which 134Cs with a half-life of 2.07 years and 137Cs with a half-life of 30.3 years. Cesium was discovered spectroscopically in 1860 by W. Bunsen and G. Kirchhoff in mineral water from Durkheim.

From L. caesius "bluish gray," which was the color of the cesium line in the spectroscope, + → -ium.

cesium clock
  ساعت ِ سزیوم   
sâ'at-e seziom

Fr.: horloge à cesium   

atomic fountain clock.

cesium; → clock.


Fr.: Baleine   

The Whale, or Sea Monster. A large, rather inconspicuous → constellation in the equatorial region of the sky at R.A. 1h 30m, Dec. -10°. Its brightest star (Diphda) is a 2nd magnitude and contains → Mira Ceti, the first-known variable star, and the → Seyfert galaxy M77. Abbreviation: Cet; genitive form: Ceti.

Named after the sea monster in Gk. mythology sent by Poseidon to punish the Queen → Cassiopeia for bragging that she or her daughter → Andromeda was more beautiful than the Nereides. But → Perseus rescued Andromeda.

Ketus, from Gk., Arabicized form Qeytas (قیطس).

CGS system
  راژمان ِ CGS   
râžmân-e CGS

Fr.: système CGS   

The system of → CGS units.

CGS unit; → system.

CGS units
  یکاهای ِ س.گ.ث   
yekâhâ-ye CGS (#)

Fr.: unités CGS   

A → metric system of physical units based on → centimeter (length), → gram (mass), and → second (time).

CGS, the initials of → centimeter, → gram, and → second; meter, kilogram, and second; → unit.

CH (methylidine)
   CH (متیلیدین)   
CH (methylidine)

Fr.: CH (méthylidine)   

The first molecule detected in the interstellar medium. Methylidine radical (CH) was discovered by Walter S. Adams in 1937 using coudé spectroscopy in the direction of the bright star ζ Ophiuchi at the Mount Wilson Observatory (main CH line at 4300 Å).

Chemical term based on Gk. methy "wine," cognate with Pers. mey "wine," from Mid.Pers. mad, may "wine;" Av. maδu- "wine, mead;" cf. Skt. mádhu- "honey, wine, sweet drink," O.E. medu, E. mead, M.Du. mede, Ger. Met "mead;" O.C.S. medu, Lith. medus "honey;" Rus. m'od "honey," m'édved' "bear" (literally "honey-knower"); PIE base *médhu- "honey, sweet drink."

CH molecule
  مولکول ِ متیلیدین   
molekul-e methylidine

Fr.: molécule de méthylidine   

CH (methylidine).

CH (methylidine); → molecule.

  زنجیر، زنجیره   
zanjir (#), zanjiré (#)

Fr.: chaîne   

1) A series of usually metal links passing through one another, used for various purposes.
2) A series of things connected or following in succession. → chain reaction; → proton-proton chain.

Chain, from O.Fr. chaeine, from L. catena "fetter."

Zanjir from Mid.Pers. zanjir "chain;" zanjiré, from zanjir + nuance suffix .

chain reaction
  واژیرش ِ زنجیری، واکنش ِ ~   
vâžireš-e zanjiri, vâkoneš-e ~

Fr.: réaction en chaîne   

A succession of → nuclear fissions when the neutrons released by previous fissions produce other nuclear fissions which themselves cause other reactions and the reactions goes on increasing exponentially.

chain; → reaction.

Chajnantor observatory
  نپاهشگاه ِ چاخنانتور   
nepâhešgâh-e Chajnantor

Fr.: observatoire de Chajnantor   

A high plateau site located at an altitude of 5,104 m in the Chilean Atacama desert, about 50 kilometers to the east of San Pedro de Atacama (longitude 67° 46' W, latitude 23° 02' S). It is the site of the → Atacama Large Millimeter Array.

In Kunza, the ancestral language of the people living in the region, Chajnantor or Tchacknatur means "lift-off place." It is the place of platforms for worshipping the Sun, where since immemorial time prayers and wishes lifted off (ESO book Cerca del Cielo).

Âftâbparast (#)

Fr.: Caméléon   

The Chameleon. A small inconspicuous → constellation in the southern hemisphere near → Crux, lying at approximate position: R.A. 11 h, Dec. -80°. Abbreviation: Cha; genitive form: Chamaeleonis;

From O.Fr. chaméléon, from L. chamaeleon, from Gk. khamaileon, from khamai "on the ground" (akin to chthon "earth;" cf. Av. zam- "the earth," Mid.Pers. zamig, Mod.Pers. zami, zamin "the earth," Skt. ksam, L. homo "earthly being" and humus "the earth," PIE *dh(e)ghom "earth") + leon "lion."

Âftâbparast "chameleon," literally "sun adorer," from âftâb "Sun, sunlight" + parast "worshipper,"

otâqak (#)

Fr.: chambre   

An enclosed space making part of a laboratory apparatus, such as → bubble chamber, → cloud chamber, → multiwire proportional chamber.

M.E., from O.Fr. chambre, from L.L. camera "a chamber, room."

Otâqak "small room, small chamber," cf. Sogdian ôtâk "place, region," ôtâkcik "local, regional, native" + -ak diminutive suffix.

champagne effect
  اسکر ِ شامپانی   
oskar-e šâmpâyn

Fr.: effet champagne   

Blowing out of → ionized gas from a → molecular cloud when the → ionization front of an → H II region created by an → embedded  → massive star arrives at the molecular cloud edge. The large → pressure gradient set up between the H II region and the → interstellar medium ejects the ionized material with velocities larger than 30 km/s, in a way comparable to champagne flowing out of a bottle.

From a hydrodynamical model first proposed by Guillermo Tenorio-Tagle (1979). Champagne, Fr., short for vin de Champagne "wine from Champagne," a historical region at northeast France, from L.L. campania "flat open country," from L. campus "field;" → effect.

champagne flow
  تچان ِ شامپانی   
tacân-e šâmpâyn

Fr.: flot champagne   

The flow of → ionized gas escaping from a → molecular cloud due to the → champagne effect.


Chandler wobble
  پلاپل ِ چاندلر   
palâpel-e Candler

Fr.: mouvement de Chandler   

Small-scale variations in the position of the Earth's geographical poles within an irregular circle of 3 to 15 metres in diameter. It seems to result from two nearly circular components, a seasonal variation in the mass distribution on the Earth (ice, snow, atmosphere) and movements of matter within the Earth.

Named after Seth Carlo Chandler (1846-1913), the American astronomer who discovered the phenomenon; → wobble.

Chandra X-ray Observatory
  نپاهشگاه ِ پرتوهای ِ X ِ چاندرا   
nepâhešgâh-e partowhâ-ye X-e Chandra

Fr.: Observatoire des rayons X Chandra   

An astronomy satellite launched by NASA in 1999 July, specially designed to detect X-ray emission from very hot regions of the Universe such as exploded stars, clusters of galaxies, and matter around black holes. Chandra carries a high resolution mirror (aperture 1.2 m, focal length 10 m), two imaging detectors (HRC and ACIS), and two sets of transmission grating spectrometer (LETG and HETG). Important Chandra features are: an order of magnitude improvement in spatial resolution, good sensitivity from 0.1 to 10 keV, and the capability for high spectral resolution observations over most of this range. Chandra was initially given an expected lifetime of 5 years, but on 4 September 2001 NASA extended its lifetime to 10 years "based on the observatory's outstanding results." Among the results obtained using Chandra one can mention the spectacular image of the → supernova remnant Cassiopeia A. See also → X-ray astronomy.

Initially called Advanced X-ray Astrophysics Facility (AXAF), the satellite was renamed the Chandra X-ray Observatory in honor of Subrahmanyan Chandrasekhar, the 1983 Nobel Prize in Physics, → Chandrasekhar limit. Moreover, Chandra, or candra- means "moon" or "shining" in Skt., from cand- "to give light, shine;" cf. Gk. kandaros "coal;" L. candela "a light, torch," from candere "to shine;" → X-ray; → Observatory.

Chandrasekhar limit
  حدِ چاندراسکهار   
hadd-e Chandrasekhar (#)

Fr.: limite de Chandrasekhar   

A limiting mass of about 1.44 Solar masses that the theory predicts a non-rotating → white dwarf can attain without collapsing to become a → neutron star or a → black hole. Over this → critical mass, the degeneracy pressure will be unable to bear the load of the bulk mass.

Named after Subrahmayan Chandrasekhar (1910-1995), Indian-born American astrophysicist who, with William A. Fowler, won the 1983 Nobel Prize for Physics for his research on white dwarfs; → limit.

  ۱) دگرشد، دگرکرد، دگرش؛ ۲) دگر‌شدن، دگر‌کردن، دگریدن، آلشیدن   
1) degaršod, degarkard, degareš, âleš 2) degar šodan (#), degar kardan (#), âlešidan, degaridan

Fr.: 1) changement; 2) changer   

1) The act of changing; alteration or variation of any kind. → adiabatic change, → canonical change, → polytropic change, → secular change, → exchange.
2a) ( To alter, modify, or make different; to make to pass from one state to another; to exchange.
2b) To transform or convert.
2c) To substitute another or others for; exchange for something else, usually of the same kind.
2b) (v.intr.) To undergo change.

M.E., from O.Fr. changier, from L.L. cambiare, from L. cambire "to exchange, barter," of Celtic origin, cf. Breton kamm "curved, bent;" Gk. kampe "a corner, a joint;" L. campus "a field;" Lith. kampus "corner;" PIE *kamb- "to bend, crook."

Degaršod, from degar, digar "another, other" (Mid.Pers. dit, ditikar "the other, the second," O.Pers. duvitiya- "second," Av. daibitya-, bitya- "second," Skt. dvitiya- "second," PIE *duitiio- "second") + šod, past stem and contracted infinitive of šodan "to become; to be; to be elapsed;" (Mid.Pers. šutan, O.Pers. šyav-, Av. šav-, šyav- "to move, to go away from" (perf. ptcpl. pass. šuta-); cf. Skt. cyavate "stirs himself, goes," stem cyu-, Gk. kinein "to move," L. ciere "to move, set in motion, stir," PIE *kei- "to move to and fro"); degarkard with kardan, → -ize; degaridan, infinitive from degar + -idan, → -ize.
Âleš, ultimately from Proto-Ir. *harH- "to barter, trade, exchange, pay tribute" (Cheung 2007); cf. Mid.Pers. harg, halg "duty, tribute; work, effort" (loaned in Ar. as xarj "expense," harâj "tax"); Sogd. arsk "work, action;" Yaghnobi ark "work;" Yidgah horγ, Munji hôr(g) "work;" Khotanese hära- "thing, possession;" prefixed forms from *hi-harH-: Mod.Pers. wihir- "change;" Mod.Pers. guhar, gohari, gahul, gahulidan "to change, exchange."

  ۱) ورشون؛ ۲) شیوار   
1) varšun; 2) šivâr

Fr.: chaos   

1a) General: A condition or place of great disorder or confusion.
1b) Math., Physics: Highly disordered evolution of some → dynamical systems which is sensitively dependent on → initial conditions. In a → chaotic system the → aperiodic, → nonlinear evolution grows → exponentially with time. Ordinary chaos is not → turbulence, but turbulence is always chaotic.
2) In → astrogeology, a distinctive area of fractured terrain on a planet or satellite, e.g. Gorgonum Chaos located in the southern hemisphere of Mars.

Chaos, in Gk. mythology and cosmology, the void existing at the beginning of the creation, as evoked in Hesiod's (c. 850 B.C.) Theogony. However, the meaning of chaos, used by Hesiod, is a matter of debate. Some have interpreted it as the primeval absence of order (hence → confusion). Subsequently, the Roman writer Ovid (43 BC-17? AD) described Chaos in his Metamorphoses as an unordered and formless primordial mass, and opposed Chaos to Cosmos "the ordered universe."

Chaos "gaping void," from L. chaos, from Gk. khaos "abyss, that which gapes wide open, is vast and empty," from *khnwos, from PIE base *gheu-, *gh(e)i- "to gape."

1) Varšun, from Tabari varâšun, Gilaki varâšin, daršin, uršin all meaning "confused, unordered, untidy," cf. Qomi šur-o-šin "chaos, confusion". The stem šun-/šin- is related to Mod.Pers. šân- in afšândan, šândan "to disperse, scatter, stew" (Mid.Pers. afšândan "to spread, scatter"), Gilaki šondan "to disperse," Hamadani šuândan "to derange, disorder," Laki veršânâ "to disperse, scatter," Šuštari šayn "to shake, agitate," Kermâni owšin "a winnowing fork to separate chaff from the grain," Laki šovâné "scattered household furniture," Tabari timšan "sowing seeds;" all ultimately from Proto-Ir. *šan- "to shake;" see also → confuse. The prefix var-, variant bar- "up, over" (as well as dar- "in"), denotes "disorder, confusion" as in darham barham "upside-down, helter-skelter".
2) Šivâr "depression between two terrains," from Tabari; probably a variant of šiyâr, → groove.

chaos theory
  نگره‌ی ِ ورشون   
negare-ye varšun

Fr.: théorie du chaos   

The theory of unpredictable behavior that can arise in systems obeying deterministic scientific laws.

theory; → chaos.

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