An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1310
Charpak's detector
  آشکارگر ِ شرپک   
âškârgar-e Charpak

Fr.: détecteur de Charpak   

An elementary particle detector using a special apparatus capable of operating at high rates. The detector consists of an → array of many closely spaced parallel wires, or → anodes, in an enclosure filled with a carefully chosen gas. The wires, being placed between two → cathode plates, are under high voltage. Each wire acts as an independent → proportional counter. The particle that passes through the chamber will ionize surrounding gaseous atoms. The resulting ions and electrons are accelerated by the electric field around the wire, causing a localized cascade of ionization which brings about an electric current proportional to the energy of the detected particle. Previous detectors, such as the → bubble chamber, could record the tracks left by particles on photographic emulsions at the rate of only one or two per second. In comparison, the multiwire chamber records up to one million tracks per second in three dimensions with an accuracy of a tenth of a millimeter and moreover sends the data directly to a computer for analysis. The speed and precision of the multiwire chamber has revolutionized high-energy physics. For instance it was crucial in finding the predicted → W boson and → Z boson of the → electroweak interaction theory. Charpak's chamber also has applications in medicine, biology, and industry. Also called → multiwire proportional chamber.

In honor of Georges Charpak (1924-2010), a French physicist, who built the first detector of this type in 1968. He received the Nobel Prize for physics in 1992; → detector.


Fr.: chasme   

In astrogeology, long, narrow, steep sided depressions on planets and Moon, for example, Melas Chasma and Candor Chasma on Mars.

L. chasma, from Gk. khasma "yawning hollow, gulf," related to khaskein "to yawn," and thus to → chaos (1).

Karz "big fissure in a mountain," from Qâeni dialect.

Chelyabinsk meteor
  شهاب ِ چلیابینسک   
šahâb-e Chelyabinsk

Fr.: météore de Tcheliabinsk   

A → meteor exploded on February 15, 2013 over Chelyabinsk, southern Russia.The explosion occurred at a height of 20 km above Earth, releasing 500 kilotons → TNT equivalent of energy, approximately 30 times the yield of the nuclear bomb over Hiroshima. It caused a → shock wave that damaged 7,200 buildings in six Russian cities and injured some 1,500 people, mainly from flying glass. Later, about five tons of meteoritic material reached the ground, including a 650 kg → meteorite that was recovered by divers from the bottom of Lake Chebarkul, on the slopes of the southern Ural mountains. With an estimated initial mass of about 12,000-13,000 metric tons, and measuring about 20 m in diameter, it is the largest known natural object to have entered Earth's atmosphere since the 1908 → Tunguska event.

Chelyabinsk, a city in Russia, the capital of the Chelyabinsk region, on the eastern slope of the Ural Mountains on the Miass River, 200 km south of Ekaterinburg and 1,879 km east of Moscow. The population of Chelyabinsk is about 1,183,000 (2015), the area, 530 sq. km; → meteor.

šimi- (#)

Fr.: chimi-   

A combining form meaning "chemical, chemically induced, chemistry," used in the formation of compound terms like → chemosynthesis. Also chem- (before a vowel) and chemo-.

Chemi- extracted from → chemical or → chemistry.

  شیمیایی، شیمیک   
šimiyâyi (#), šimik

Fr.: chimique   

Of, relating to, used in, or produced by means of chemistry.

From chemic "of alchemy," → chemistry + → -al.

Šimiyâyi, of or pertaining to šimichemistry.
Šimik, from šim- + -ik, → -ic.

chemical abundance
  فراوانی ِ شیمیایی   
farâvâni-ye šimiyâyi (#)

Fr.: abondance chimique   

The relative amount of a given → chemical element or → chemical compound with respect to another element or compound in a given sample.

chemical; → abundance.

chemical adsorption
  برشم ِ شیمیایی   
baršam-e šimiyâyi

Fr.: adsorption chimique   

Same as → chemisorption.

chemical; → adsorption.

chemical bond
  بند ِ شیمیک، ~ شیمیایی   
band-e šimik, ~ šimiyâyi

Fr.: liaison chimique   

A force by which chemical substances are held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons.

chemical; → bond.

chemical composition
  همنهش ِ شیمیک   
hamneheš-e šimik

Fr.: composition chimique   

The identities, and relative abundances of the → chemical elements or → compounds that make up a substance.

chemical; → composition.

chemical compound
  چندساخت ِ شیمیایی   
candsâxt-e šimiyâyi

Fr.: composé chimique   

A substance whose molecules are made up of atoms of at least two different elements.

chemical; → compound.

chemical element
  بن‌پار ِ شیمیایی، عنصر ِ ~   
bonpâr-e šimiyâyi (#), onsor-e ~ (#)

Fr.: élément chimique   

A substance which consists entirely of atoms of the same → atomic number and cannot be decomposed or changed into another substance using chemical means. Currently 118 chemical elements are known, the most abundant being → hydrogen. → periodic table.

chemical; → element.

chemical enrichment
  پرداری ِ شیمیایی   
pordâri-ye šimiyâyi

Fr.: enrichissement chimique   

The → process by which the relative → abundance of a given → chemical element or → species in an → astrophysical object is increased. For example the the → increase of the → heavy element content of the → interstellar medium due to → stellar evolution.

chemical; → enrichment.

chemical equation
  هموگش ِ شیمیایی   
hamugeš-e šimiyâyi

Fr.: équation chimique   

The symbolic representation of a chemical reaction where the formulae of the → reactants are placed on the left and the formulae of → products on the right of an arrow.

chemical; → equation.

chemical evolution
  فرگشت ِ شیمیایی   
fargašt-e šimiyâyi (#)

Fr.: évolution chimique   

A cumulative change in the chemical properties, or more specifically, the relative abundances of chemical elements in an astrophysical system.

chemical; → evolution.

chemical mixing
  آمیزش ِ شیمیایی، ~ شیمیک   
âmizeš-e šimiyâyi, ~ šimik

Fr.: mélange chimique   

mixing process.

chemical; → mixing.

chemical potential
  توند ِ شیمیک   
tavand-e šimik

Fr.: potentiel chimique   

For a given component in a → gas mixture, the change in → Gibbs free energy (G) with respect to change in amount of the component (n), when pressure, temperature, and amounts of other components remain constant: ∂G/∂n. Components are in equilibrium if their chemical potentials are equal.

chemical; → potential.

chemical reaction
  واژیرش ِ شیمیایی، واکنش ِ ~   
vâžireš-e šimiyâyi, vâkoneš-e ~

Fr.: réaction chimique   

A → change or → transformation in which a → substance → decomposes, → combines with other → substances, or interchanges constituents with other substances.

chemical; → reaction.

chemical separation
  جدایی ِ شیمیایی   
jodâyi-ye šimiyâyi

Fr.: séparation chimique   

The physical processes that can cause certain elements to migrate in a → stellar atmosphere. These processes are thought to be important in creating the chemical peculiarities seen in → Am stars and → Ap stars.

chemical; → separation.

chemical species
  آرز ِ شیمییایی   
âraz-e šimiyâyi

Fr.: espèce chimiique   

A set of chemically → identical  → atomic or → molecular entities.

chemical; → species.

chemically peculiar star
  ستاره‌ی ِ شیمیکانه افد   
setâre-ye šimikâné afd

Fr.: étoile chimiquement particulière   

A → main sequence star of → spectral type A or B (→ A-type star, → B-type star) identified by the presence of anomalously strong or weak → absorption lines of certain elements in their spectra. CP stars have been divided into four main classes on the basis of their spectra: 1) non-magnetic metallic-lined (CP1, → Am star), magnetic (CP2, → Ap star), non-magnetic mercury-manganese (CP3, → HgMn star), and helium-weak (CP4, → He-weak star).
See also → Ap/Bp stars.

chemical; → -ly; → peculiar; → star.

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