An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

<< < K c Kep keV kin Koz > >>

Number of Results: 89
kinetic helicity
  پیچاری ِ جنبشی   
picari-ye jonbeši

Fr.: hélicité cinétique   

In fluid mechanics, a quantity that describes helical flow. It is defined by the integrated scalar product of the velocity field and the → vorticity: KK = ∫ dVu . ( x u). In the absence of magnetic field, this quantity is conserved by the → Euler equation. See also → magnetic helicity.

kinetic; → helicity.

kinetic potential
  توند ِ جنبشیک   
tavand-e jonbešik

Fr.: potentiel cinétique   

Same as → Lagrangian function.

kinetic; → potential.

kinetic temperature
  دمای ِ جنبشی   
damâ-ye jonbeši (#)

Fr.: température cinétique   

The temperature of a gas defined in terms of the average kinetic energy of its atoms or molecules.

kinetic; → temperature.

kinetic theory of gases
  نگره‌ی ِ جنبشی ِ گاز‌ها   
negare-ye jonbeši-ye gâzhâ (#)

Fr.: théorie cinétique des gaz   

A theory that explains macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion.

kinetic; → theory; → gas.

Kippenhahn diagram
  نمودار ِ کیپنهان   
nemudâr-e Kippenhahn

Fr.: diagrame de Kippenhahn   

A plot representing the evolution of the internal structure of a star as a function of time. The x-axis indicates the time, the y-axis the mass, and a color or shading specifies convective regions. A vertical line through the graph corresponds to a model at a particular time.

Named after Rudolf Kippenhahn (1926-), a German astrophysicist; → diagram

Kirchhoff's law
  قانون ِ کیرشهوف   
qânun-e Kirchhoff (#)

Fr.: loi de Kirchhoff   

The radiation law which states that at thermal equilibrium the ratio of the energy emitted by a body to the energy absorbed by it depends only on the temperature of the body.

Gustav Robert Kirchhoff (1824-1887), a German physicist who made major contributions to the understanding of electric circuits, spectroscopy, and the emission of black-body radiation from heated objects; → law.

Kirkwood gaps
  گاف‌های ِ کرک‌وود   
gâfhâ-ye Kirkwood (#)

Fr.: lacunes de Kirkwood   

Regions in the asteroid belt within which few asteroids are found. The Kirkwood gaps are due to the perturbing effects of Jupiter through resonances with Jupiter's orbital period.

Named for the American astronomer Daniel Kirkwood (1814-1895), who Discovered them in 1866; → gap.

Kleinmann-Law nebula
  میغ ِ کلاینمن-لاؤ   
miq-e Kainman-Law

Fr.: nébuleuse de Kleinmann-Law   

An strong, extended infrared source in the Orion Nebula, about 1 arcminute NW of the Trapezium and about 12 arcseconds south of the → Becklin-Neugebauer object. It dominates the infrared emission at wavelengths above 20 microns. It probably represents a cluster of young and forming stars embedded in a dusty molecular cloud.

Named after Douglas E. Kleinmann (1942-) and Frank J. Low (1933-), who first studied this object in 1967; → nebula.

Klotho
  کلوتو   
klotho (#)

Fr.: Klotho, Clotho   

A → main belt asteroid (97) discovered by the German astronomer Ernst W. Temple in 1868 working at Marseille Observatory.

Named after Klotho (literally "spinner") the Gk. goddess of fate who spins the thread of life, from klothein "to spin."

klystron
  کلیسترون   
klistron (#)

Fr.: klystron   

An electron tube for converting direct-current energy into radio frequency energy by alternately speeding up and slowing down the electrons. It is used as a microwave amplifier or oscillator in radar and high-frequency radio work.

From Gk. kluzein, klus- "to wash, break over" + -tron.

knee
  زانو   
zânu (#)

Fr.: genou   

1) The joint of the leg that allows for movement between the femur and tibia and is protected by the patella; the central area of the leg between the thigh and the lower leg.
2) Something resembling a bent knee, especially a rigid or braced angle between two framing members (Dictionary.com). → alpha element knee

M.E. kne; O.E. cneo, cneow "knee" (cognates: O.Norse kne, O.Sax. kneo, M.Du. cnie, Dutch knie, O.H.G. kniu, Ger. Knie; cf. Pers. zânu, as below.

Zânu "knee," Mid.Pers. šnûg "knee;" Av. žnu- "knee;" cognates: Skt. jānu-, Hittite genu "knee;" Gk. gonu "knee," gonia "corner, angle;" L. genu "knee;" O.E. cneo, as above; PIE *gnéwo-.

knife
  کارد   
kârd (#)

Fr.: couteau   

1) An instrument for cutting, consisting essentially of a thin, sharp-edged, metal blade fitted with a handle.
2) Any blade for cutting, as in a tool or machine (Dictionary.com).

M.E. knif; O.E. cnif, probably from O.N. knifr; cf. M.L.G. knif, M.Du. cnijf, Ger. Kneif; of uncertain origin.

Kârd "knife," from Mid.Pers. kârt "knife;" Av. karət- "to cut;" cf. Skt. kart- "to cut," karəta- "knife;" Proto-Ir. *kart- "to cut."

knife-edge test
  آزمون ِ کارد   
âzmun-e kârd (#)

Fr.: contrôle par foucaultage   

The same as → Foucault knife-edge test.

knife; → edge; → test.

know
  دانستن   
dânestan (#)

Fr.: savoir   

1) To perceive or understand as fact or truth; to apprehend clearly and with certainty.
2) To have established or fixed in the mind or memory (Dictionary.com).

M.E. knowen, knawen, from O.E. cnâwan, akin to O.H.G. bichnâan "to recognize," L. gnoscere, noscere "to come to know," Gk. gignoskein, Pers. šenâxtan, dânestan, as below.

Dânestan "to know;" Mid.Pers. dânistan "to know;" variant šenâxtan, šenâs- "to recognize, to know" (Mid.Pers. šnâxtan, šnâs- "to know, recognize"); O.Pers./Av. xšnā- "to know, learn, come to know, recognize;" cf. Skt. jñā- "to recognize, know," jānāti "he knows;" Gk. gignoskein "to know, think, judge," cognate with L. gnoscere, noscere "to come to know" (Fr. connaître; Sp. conocer); P.Gmc. *knoeanan; O.E. cnawan, E. know, as above; Rus. znat "to know;" PIE base *gno- "to know."

knowledge
  شناخت   
šenâxt (#)

Fr.: connaissance   

1) All the information, facts, truths, and principles learned throughout time.
2) Acquaintance with facts, truths, or principles, as from study or investigation.

M.E. cnawlece, from O.E. cnawan, cf. O.H.G. bi-chnaan, ir-chnaan "to know;" cognate with Pers. šenâxt, as below.

Šenâxt, past stem of šenâxtan, šenâsidan "to know, discern, distinguish, be acquainted with;" Mid.Pers. šnâxtan, šnâs- "to know, recognize," dânestan "to know;" O.Pers./Av. xšnā- "to know, learn, come to know, recognize;" cf. Skt. jñā- "to recognize, know," jānāti "he knows;" Gk. gignoskein "to know, think, judge;" L. gnoscere, noscere "to come to know" (Fr. connaître; Sp. conocer); O.E. cnawan; E. know; Rus. znat "to know;" PIE base *gno- "to know."

Knudsen layer
  لایه‌ی ِ کنودسن   
lâye-ye Knudsen

Fr.: couche de Knudsen   

The thin layer of → vapor immediately adjacent to an irradiated surface. The thickness of the Knudsen layer is generally recognized to be in the order of a few → mean free paths from the surface.

Named after Danish physicist Martin Knudsen (1871-1949); → layer.

Kochab (β Ursae Minoris)
  کوکب   
Kowkab (#)

Fr.: Kochab   

The second brightest star in the constellation → Ursa Minor. It is a reddish, evolved → giant of → spectral type K4 with a visual magnitude of 2.1. It is almost 500 times more luminous than the Sun and lies at a distance of 126 light years. Also called Kocab, Kochah.

Kochab, from Ar. al-Kaukab (الکوکب) "star," shortened from al-Kaukab al-shemali (الکوکب الشمالی) "North Star."

Kolmogorov constant
  پایای ِ کولموگوروف   
pâyâ-ye Kolmogorov (#)

Fr.: constante de Kolmogorov   

The proportionality constant C in Kolmogorov's mathematical analysis of → turbulence which states that the spectral energy E(k) in the range of turbulent scales is E(k) =C ε2/3 k-5/3, where k represents the → wave number (inversely proportional to the wavelength or → eddy size), and ε is the average energy dissipation per unit mass in the fluid. Experimental measurements give C close to 1.5.

Andrei Nikolaevich Kolmogorov (1903-1987), a prominent Soviet mathematician, who made major advances in different scientific fields, mainly probability theory, topology, turbulence, classical mechanics, and computational complexity; → constant.

Kolmogorov scale
  مرپل ِ کولموگوروف   
marpel-e Kolmogorov

Fr.: échelle de Kolmogorov   

Length scale of → turbulent flow below which the effects of molecular → viscosity are non-negligible.

Kolmogorov constant; → scale.

Kolmogorov spectrum
  بیناب ِ کولموگوروف   
binâb-e Kolmogorove

Fr.: spectre de Kolmogorov   

The distribution of energy over different scales in a → turbulent flow where → energy cascade occurs. Let E be the energy per unit → wave number (k) and ε the energy → dissipation parameter, E = E(k,ε). → Dimensional analysis yields: E = Cε2/3k-5/3, where C is the → Kolmogorov constant.

A. N. Kolmogorov, 1941, Local structure of turbulence in an incompressible fluid for very large Reynolds numbers, Doklady Acad Sci. USSR 31, 301; → spectrum.

<< < K c Kep keV kin Koz > >>