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: 28
young
  جوان   
javân

Fr.: jeune   

Being in the first or early stage of existence or evolution; e.g. → young stellar object.

M.E.; O.E. geong "youthful, young," from P.Gmc. *jungas (cf. O.S., O.Fris. jung, O.N. ungr, M.Du. jonc, Du. jong, O.H.G., Ger. jung, Goth. juggs), from PIE base *yeu- "vital force, youthful vigor;" cognate with Pers. javân, as below.

Javân "young;" Mid.Pers. juwân "young, youth;" Arm. yavanak (loaned from Mid.Pers.); Av. yuuan- "youth;" cf. Skt. yuvan- "young, youth;" L. juvenis "young man;" Lith. jaunas "young;" O.C.S. junu, Rus. junyj "young;" cognate with E. young, as above.

young stellar object (YSO)
  بر آخت ِ ستاره‌ای ِ جوان   
barâxt-e setâreyi-ye javân

Fr.: objet stellaire jeune   

Any star that has evolved past the → protostar stage, but has not yet arrived on the → main sequence. There is a variety of YSOs depending on their age, mass, and environment, including → Herbig stars, → T Tauri stars, and, in general, compact infrared sources embedded in molecular clouds.

young; → stellar; → object.

Young's experiment
  آزمایش ِ یانگ   
âzmâyeš-e Young (#)

Fr.: expérience de Young   

A method of producing → interference of light. Two beams of → coherent light are produced by passing light through a very small circular aperture in one screen, then through two small circular apertures very close together in a second screen. On a third screen, behind the second screen, there will be two overlapping sets of waves and, if the light is monochromatic, → interference fringes will appear on the third screen. The experiment can also be performed with a beam of electrons or atoms, showing similar interference patterns. Young's experiment provides an evidence of the → wave-particle duality, as explained by → quantum mechanics. Same as → double-slit experiment.

Named after the English scientist Thomas Young (1773-1829), who originally performed the experiment some time around 1801 in an attempt to resolve the question of whether light was composed of particles (the → corpuscular theory of light); or rather consisted of waves travelling through some → ether. The experiment proved the wave nature of light; → experiment.

Young's modulus
  پیمون ِ یانگ   
peymun-e Young

Fr.: module de Young   

A measure of elasticity of a material, defined as the ratio of tensile → stress to tensile → strain, which equals the ratio of compressive stress to compressive strain.

Named after Thomas Young, → Young's experiment.

youth paradox
  پارادخش ِ جوانی   
pârâdaxš-e javâni

Fr.: paradoxe de jeunesse   

Same as → paradox of youth.

ytterbium
  ایتربیوم   
iterbiom (#)

Fr.: ytterbium   

A soft, malleable, silver-white metallic chemical element; symbol Yb. Atomic number 70; atomic weight 173.04; melting point 819°C; boiling point about 1,194°C; specific gravity about 7.0. It has several radioactive isotopes.

From Ytterby, the name of the Swedish village where the mineral ytterbite (the source of ytterbium) was originally found. It was discovered by the Swiss chemist Jean-Charles Galissard de Marignac in 1878.

yttrium
  ایتریوم   
itriom (#)

Fr.: yttrium   

A highly crystalline iron-gray metallic chemical element; symbol Y. Atomic number 39; atomic weight 88.9059; melting point about 1,522°C; boiling point 3,338°C; specific gravity about 4.45. It has several radioactive isotopes.

From ytterbite, → ytterbium, which turnd out to be containing two different elements.

Yukawa potential
  توند ِ یوکاوا   
tavand-e Yukawa

Fr.: potentiel de Yukawa   

The potential function that is associated with the strong, short-ranged force resulting from the exchange of massive particles between two → nucleons in the same atomic nucleus. The potential has the form of V(r) = C. (1/r) exp (-K.r), where r is the distance between the nucleons and C and K are constants, giving measures of the strength and range of the force respectively.

In honor of the Japanese physicist Hideki Yukawa (1907-1981), winner of the 1949 Nobel Prize in Physics; → potential.

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