An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 142 Search : erg
activation energy
  کاروژ ِ ژیرانش   
kâruž-e žirâneš

Fr.: énergie d'activation   

Chemistry: The minimum amount of energy that is required to activate → atoms or → molecules to a condition in which they can undergo a → chemical reaction. Most reactions involving neutral molecules cannot take place at all until they have acquired the energy needed to stretch, bend, or otherwise distort one or more → bonds. In most cases, the activation energy is supplied by → thermal energy.

activation; → energy.



1) A broad glowing arc of radiance, sometimes seen high in the western sky at → twilight, caused by the → scattering effect of → fine dust particles suspended in the → upper atmosphere.
2) Lingering → radiation that remains after a violent → event such as a → gamma-ray burst. The afterglow of any gamma-ray burst is caused by an event different from the original explosion, likely by → shock waves colliding with the ambient medium. Afterglows occur in a large range of → electromagnetic  → wavelengths.

after; → glow.

alternative energy
  کاروژ ِ دگرینه   
kâruž-e degarine-ye

Fr.: énergie alternative   

Energy from a source other than the conventional fossil fuel sources.

alternative; → energy.

anbar (#)

Fr.: ambre gris   

A wax-like, ash-colored, strongly scent substance present in the intestines of → whales and found in seas or cast ashore. Used in perfumery.

From M.Fr. ambre gris "gray amber," → gray; → amber.

Anbar "ambergris," from Mid.Pers. ambar.

angle of emergence
  زاویه‌ی ِ زمرچش   
zâviye-ye zomarceš

Fr.: angle d'émergence   

The angle of the light coming out of a medium. For a medium with parallel sides (such as a glass slab) it is equal to the angle of incidence.

angle; → emergence.

angular kinetic energy
  کاروژ ِ جنبشی ِ زاویه‌ای   
kâruž-e jonbeši-ye zâviye-yi

Fr.: énergie cinétique angulaier   

Same as → rotational energy.

angular; → kinetic; → energy.

binding energy
  کاروژ ِ بندش، ~ همگیری   
kâruž-e bandeš, ~ hamgiri

Fr.: énergie de liaison   

1) Of a gravitational system, the difference in energies between the hypothetical state where all bodies of the system are infinitely separated from each other and the actual bound state.
2) The energy which must be supplied to a nucleus in order to cause it to decompose into its constituent neutrons and protons.

Binding, noun from → bind; → energy.

Kâruž, → energy; bandeš noun from bandidan, → bind.

black hole merger
  تشک ِ سیه‌چالها   
tašk-e siyah-câlhâ

Fr.: fusion de trous noirs   

The collision of two → black holes in a → binary black hole system once they come so close that they cannot escape each other's gravity. They will merge in an extremely violent event to become one more massive black hole. The merger would produce tremendous energy and send massive ripples, called → gravitational waves, through the → space-time fabric of the Universe. Such an event (called GW150914) was first detected by the → Laser Interferometer Gravitational-Wave Observatory (LIGO) on September 14, 2015. The initial black hole masses were 36 and 29 Msun which gave a final black hole mass of 62 Msun, with 3 Msun radiated in gravitational waves. The event happened at a distance of 1.3 billion → light-years from Earth (Abbott et al., 2016, Phys. Rev. Lett. 116, 061102). Black hole merger is preceded by → inspiral and followed by → ringdown.

black; → hole; → merger.

blue supergiant
  ابرغول ِ آبی   
abarqul-e âbi

Fr.: supergéante bleue   

An evolved star of spectral type O, B, or A; e.g. → Rigel, → Deneb.

blue; → supergiant.

characteristic thermal energy
  کاروژ ِ گرمایی ِ سرشتاری   
kâruž-e garmâyi-ye sereštâri

Fr.: énergie thermique caractéristique   

The quantity kT in the → Maxwell-Boltzmann distribution law, where k is → Boltzmann's constant and T the gas temperature. See also → thermal energy.

characteristic; → thermal; → energy

cohesive energy
  کاروژ ِ همدوسش   
kâruž-e hamduseš

Fr.: énergie de cohésion   

The energy associated with the chemical bonding of atoms in a solid.

cohesive; → energy.

conservation of energy
  پتایش ِ کاروژ   
patâyeš-e kâruž

Fr.: conservation d'énergie   

The → principle whereby the → total energy of a → closed system remains → constant. This means that energy can neither be created nor destroyed. See also the → first law of thermodynamics.

conservation; → energy.

conservation of mass and energy
  پتایش ِ جرم و کاروژ   
patâyeš-e jerm o kâruž

Fr.: conservation de masse et d'énergie   

A principle, resulting from Einstein's theory of → special relativity whereby in any → closed system the sum of mass and energy remains → constant.

conservation; → mass; → energy.

hamgerâyidan (#)

Fr.: converger   

1) General: To tend to meet in a point; incline toward each other.
2) Math: (of an infinite series) to have a finite sum. (of an improper integral) to have a finite value.

From L.L. convergere "to incline together" from → com- "together" + vergere "to bend."

Hamgerâyidan, from ham- "together," → com- + gerâyidan "to incline toward, verge on; to intend," Mid.Pers. grayidan "to lean, incline; to intend, desire," → diverge.

hamgerâyi (#)

Fr.: convergence   

1) General: Act or state of converging.
2) Math: The property of a → sequence or → series which ensures that it will approach a definite → finite limit. See also: → divergence.

From converg-, from → convergent + -ence, equivalent to → -ance.

Hamgerâyi, verbal noun from hamgerâyidan, → converge.

hamgerâ (#)

Fr.: convergent   

Coming together, as a light beam after passing through a convex lens which brings the beam into the focus.

Verbal ddj. from → converge.

converging mirror
  آینه‌ی ِ همگرا   
âyene-ye hamgerâ (#)

Fr.: miroir convergent   

A concave mirror that reflects a parallel beam into a convergent beam.

From → converge + → -ing; → mirror.

cool hypergiant
  هیپرغول ِ سرد   
hiperqul-e sard

Fr.: hypergéante froide   

A highly unstable, → very massive star lying just below the empirical upper luminosity boundary in the → H-R diagram (→ Humphreys-Davidson limit) with spectral types ranging from late A to M. Cool hypergiants very likely represent a very short-lived evolutionary stage, and are distinguished by their high → mass loss rates. Many of them also show photometric and spectroscopic variability, and some have large → infrared excesses and extensive circumstellar ejecta. The evolutionary state of most of these stars is not known but they are all → post-main-sequence stars (Humphreys, 2008, IAUS 250).

cool; → hypergiant.

cosmic energy equation
  هموگش ِ کاروژ ِ کیهانی   
hamugeš-e kâruž-e keyhâni

Fr.: équation de l'énergie cosmique   

Same as the → Layzer-Irvine equation.

cosmic; → energy; → equation.

Coulomb energy
  کاروژ ِ کولن   
kâruž-e Coulomb

Fr.: énergie coulombienne   

The → potential energy from which derives the repulsive electrostatic force between two → charged particles. For example, the Coulomb energy between two protons is e2/r ~ 0.5 MeV, which is small compared with the average → binding energy per particle (~ 8 Mev). However the Coulomb repulsion becomes important for heavy nuclei. The total Coulomb energy of a nucleus is given by: (3/5) Z(Z - 1)e2/R, where Z is the → atomic number, e the charge, and R the nuclear radius. Since R ∝ A1/3 and Z is roughly proportional to A, the Coulomb energy is roughly proportional to A5/3. On the other hand, the total binding energy is proportional to A, which means that the relative importance of the repulsive electrostatic energy increases with increasing mass number as A2/3.

coulomb; → energy.

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