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: 61 Search : gene
-genesis
   -زایی   
-zâyi (#)

Fr.: -génèse   

A combining form of genesis.

From L. genesis, from Gk. genesis "origin, generation," from gignesthai "to be born," related to genos "race, birth, descent," cognate with Pers. zâdan "to bring forth, give birth," → generate.

anisotropic homogeneous cosmological model
  مدل ِ کیهانشناختی ِ همگن و نا-ایزوگرد   
model-e keyhânšenâxti-ye hamgen o nâ-izogard

Fr.: modèle cosmiologique homogène mais anisotrope   

A solution to Einstein's theory of → general relativity that is spatially homogeneous but allows for rotation and/or shear. See also → Bianchi cosmological model.

anisotropic; → homogeneous; → cosmological; → model.

baryogenesis
  باریونزایی   
bâriyonzâyi

Fr.: baryogénèse   

The hypothetical mechanism of creating the → baryon asymmetry in the → Universe. Universe. Explaining the observed matter asymmetry is an important open question in physical cosmology. → Sakharov conditions.

From baryo-, from → baryon + → -genesis.

Cretaceous-Paleogene extinction event
  رویداد ِ خاموشی ِ گچاسا-پارینزاد   
ruydâd-e xâmuši-ye Gacâsâ-Pârinzâd

Fr.: extinction Crétacé-Tertiaire   

The → mass extinction event that destroyed the dinosaurs and a majority of other species on Earth approximately 65 million years ago. This event is believed to have been the impact of a 10 km-size → asteroid or → comet nucleus and its aftereffects, including a severe → impact winter. Same as the → Cretaceous-Tertiary event.

Cretaceous; → Paleogene; → extinction; → event.

degeneracy
  واگنی   
vâgeni (#)

Fr.: dégénérescence   

1) General: Degenerate state or character. Reverting to an earlier, simpler, state.
2) Math.: Limiting case in which a class of object changes its nature so as to belong to another, usually simpler, class.
3) Physics: In quatum mechanics, the condition in which two or more different → wave functions of a system correspond to the same energy. In the case of atomic energy levels, the degeneracy can be removed, for example, by applying an electric field to the atom.
State or charcater of → degenerate matter.

From degener(ate), → degenerate, + -acy suffix of nouns of quality and state.

Vâgeni, from vâgen, → degenerate, + noun suffix -i.

degeneracy pressure
  فشار ِ واگنی   
fešâr-e vâgeni (#)

Fr.: pression de dégénérescence   

Pressure in a degenerate electron or neutron gas. → degenerate matter.

degeneracy; → pressure.

degenerate
  واگن   
vâgen (#)

Fr.: dégénéré   

Characterized by or associated with → degeneracy.

L. degeneratus, p.p. of degenerare "depart from one's kind, fall from ancestral quality," from → de- + gener-, stem of genus "race, stock, kind," gignere "to beget," cf. with Gk. genos "race, kind," gonos "birth, offspring," from PIE base *gen-/*gon-/*gn- "to produce, beget, be born," cf. Av. zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born," zana- "race" (in sruuô.zana- "belonging to the race of the horned ones"), O.Pers. zana- "tribe" (in paru-zana- "consisting of many tribes"), Skt. janati "begets, bears," jana- "creature, human being, race, tribe, people."

Vâgen, from vâ-, → de-, + gen "kind," (as in hamgen "of the same kind, like each other; friend, partner," from ham- "together," → com- + gen "kind," O.Pers./Av. zana- "race; tribe," cognate with L. genus, as above). Alternatively, gen may be a variant of Mid./Mod.Pers. gôn/gun "kind, type; manner; color, skin color," from Av. gaona- "hair, hair color, color."

degenerate dwarf
  کوتوله‌ی ِ واگن   
kutule-ye vâgen

Fr.: naine dégénérée   

Same as → white dwarf.

degenerate; → dwarf.

degenerate matter
  ماده‌ی ِ واگن   
mâdde-ye vâgen (#)

Fr.: matière dégénérée   

Highly compressed matter in which the normal atomic structure has broken down and which, because of quantum-mechanical effects, exerts a pressure that is independent of temperature. Bodies with masses less than → Chandrasekhar's limit (1.4 solar masses) are supported by electron → degeneracy pressure and have densities of about 106 kg/m3. In collapsed stars of mass above 1.4 solar masses, gravity will overwhelm electron degeneracy and further collapse ensues. Electrons combine with protons to form neutrons, so producing a → neutron star. Because neutrons, like electrons, are → fermions and therefore subject to the → Pauli exclusion principle, at high enough densities, about 1014 kg/m3, neutron degeneracy pressure prevents further collapse of the star. For masses larger than 2-3 solar masses, even neutron degeneracy cannot prevent further collapse, and a → black hole is formed.

degenerate; → matter.

double-degenerate binary system
  راژمان ِ درین ِ دوبار واگن   
râžmân-e dorin-e dobâr vâgen

Fr.: système binaire doublement dégénéré   

A system of evolved → binary stars in which both → components have ejected their envelopes and evolve toward → white dwarf stage. So far a half dozen double-degenerate → binary systems are known, for example Henize 2-248 (M. Santander-Garcia et al., 2015, 518, 5).

double; → degenerate; → binary; → system.

electron degeneracy
  واگنی ِ الکترون   
vâgeni-ye elektron (#)

Fr.: dégénérescence des électrons   

A → degenerate matter in which electrons are very tightly packed together, as in a white dwarf, but cannot get closer than a certain limit to each other, because according to quantum mechanics laws (→ Pauli exclusion principle) the lowest energy levels can be occupied by only one electron. Therefore, electrons are forced into high energy states. And the significant pressure created by these high energy electrons supports white dwarf stars against their own gravity.

electron; → degeneracy.

energy generation equation
  هموگش ِ آزانش ِ کاروژ   
hamugeš-e âzâneš-e kâruž

Fr.: équation de génération d'énergie   

Of a stellar → nuclear fusion, the equation describing the → energy generation rate as a function of → density and → temperature.

energy; → generation; → equation.

energy generation rate
  نرخ ِ آزانش ِ کاروژ   
nerx-e âzâneš-e kâruž

Fr.: taux de génération d'énergie   

Of a stellar → nuclear fusion, the energy produced per unit mass per unit time, usually denoted ε (erg g-1s-1). The general form of the energy generation equation is: ε = ε0ρλTν, where ε0, ρ, and λ are constants over some efficiently restricted range of → temperature T, → density ρ, and → chemical composition. The temperature exponent ν is about 4, 15, and 40 for → proton-proton chain, → CNO cycle, and → triple alpha process, respectively.

energy; → generation; → rate.

gene
  ژن   
žen (#)

Fr.: gène   

The basic unit of hereditary that is an ordered sequence of nucleotides located in a particular position of a particular chromosome. It is the means by which characteristics are transmitted from parents to offsprings.

From Ger. Gen, coined 1905 by Danish scientist Wilhelm Ludvig Johannsen (1857-1927), from Gk. genos "race, kind," genesis "origin," genea "generation, race;" cognate with L. genus "race, stock;" generare "to bring forth;" Pers. zâdan "to bring forth;" → generate.

Žen, loanword from Fr., as above.

general
  هروین   
harvin

Fr.: général   

(Adj.) 1) Not limited to one class, field, product, service, etc. 2) Relating to the whole or to the all or most. 3) Dealing with overall characteristics, universal aspects, or important elements.
See also:
general precession, → general relativity, → generalization, → generalize, → generalized, → generalized coordinates, → generalized forces, → generalized momenta, → generalized velocities, → New General Catalogue (NGC).

From L. generalis "relating to all, of a whole class," from genus "race, stock, kind," akin to Pers. zâdan, Av. zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born;" Mod.Pers. zâdan, present stem zā- "to bring forth, give birth" (Mid.Pers. zâtan; cf. Skt. jan- "to produce, create; to be born," janati "begets, bears;" Gk. gignomai "to happen, become, be born;" L. gignere "to beget;" PIE base *gen- "to give birth, beget."

Harvin, from Mid.Pers. harvin "all," from har(v) "all, each, every" (Mod.Pers. har "every, all, each, any"); O.Pers. haruva- "whole, all together;" Av. hauruua- "whole, at all, undamaged;" cf. Skt. sárva- "whole, all, every, undivided;" Gk. holos "whole, complete;" L. salvus "whole, safe, healthy," sollus "whole, entire, unbroken;" PIE base *sol- "whole."

general precession
  پیشایان ِ هروین   
pišâyân-e harvin

Fr.: précession générale   

The secular motions of the → celestial equator and → ecliptic. In other words, the sum of → lunisolar precession, → planetary precession, and → geodesic precession.

general; → precession

general precession in longitude
  پیشایان ِ هروینِ درژنا   
pišâyân-e harvin-e derežnâ

Fr.: précession générale en longitude   

The secular displacement of the → equinox on the → ecliptic of date.

general; → precession; → longitude.

general precession in right ascension
  پیشایان ِ هروین ِ راست‌افراز   
pišâyân-e harvin-e râst afrâz

Fr.: précession générale en ascension droite   

The secular motion of the → equinox along the → celestial equator.

general; → precession; → right ascension.

general relativistic
  بازانیگی‌مند ِ هروین   
bâzânigimand-e harvin

Fr.: de relativité générale   

Of, relating to, or subject to the theory of → general relativity.

general; → relativistic.

general relativity
  بازانیگی ِ هروین   
bâzânigi-ye harvin

Fr.: relativité générale   

The theory of → gravitation developed by Albert Einstein (1916) that describes the gravitation as the → space-time curvature caused by the presence of matter or energy. Mass creates a → gravitational field which distorts the space and changes the flow of time. In other words, mass causes a deviation of the → metric of space-time continuum from that of the "flat" space-time structure described by the → Euclidean geometry and treated in → special relativity. General relativity developed from the → principle of equivalence between gravitational and inertial forces. According to general relativity, photons follow a curved path in a gravitational field. This prediction was confirmed by the measurements of star positions near the solar limb during the total eclipse of 1919. The same effect is seen in the delay of radio signals coming from distant space probes when grazing the Sun's surface. Moreover, the space curvature caused by the Sun makes the → perihelion of Mercury's orbit advance by 43'' per century more than that predicted by Newton's theory of gravitation. The → perihelion advance can reach several degrees per year for → binary pulsar orbits. Another effect predicted by general relativity is the → gravitational reddening. This effect is verified in the → redshift of spectral lines in the solar spectrum and, even more obviously, in → white dwarfs. Other predictions of the theory include → gravitational lensing, → gravitational waves, and the invariance of Newton's → gravitational constant.

general; → relativity.

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