An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 69 Search : energy
energy transfer
  تراوژ ِ کاروژ   
tarâvaž-e kâruž

Fr.: transfert d'énergie   

The → conversion of one → form of energy into another, or the movement of energy from one place or system to another.

energy; → transfer.

energy-momentum tensor
  تانسور ِ کاروژ-جنباک   
tânsor-e kâruž-jonbâk

Fr.: tenseur énergie-quantité de mouvement   

A tensor (Tμν) related to the → Einstein tensor through → Einstein's field equations. The energy-momentum tensor depends upon the distribution of the → energy and → matter in the space.

energy; → momentum; → tensor.

equipartition of energy
  هموگپاری ِ کاروژ   
hamugpâri-ye kâruž

Fr.: équipartition de l'énergie   

1) General: Equal sharing of the → total energy among all → components of a → system.
2) In the → kinetic theory of gases, the → theorem according to which → molecules in → thermal equilibrium have the same average energy (1/2 kT) associated with each independent → degree of freedom of their motion.

equi-; → part; → -tion.

excitation energy
  کاروژ ِ بر انگیزش   
kâruž-e barangizeš

Fr.: énergie d'excitation   

Amount of energy (usually measured in → electron-volts) required to bring an electron from its → ground state to a given → excited state.

excitation; → energy.

Fermi energy
  کاروژ ِ فرمی   
kâruž-e Fermi

Fr.: énergie de Fermi   

The energy of the highest occupied quantum state in a system of fermions at absolute zero temperature. See also → Fermi sea.

fermi; → energy.

Gibbs free energy
  کاروژ ِ آزاد ِ گیبس   
kâruž-e âzâd-e Gibbs

Fr.: énergie libre de Gibbs   

The total energy needed to create a thermodynamic system minus the energy provided the environment. It is defined by G = U + PV -TS, where U is the → internal energy, T the → absolute temperature, S the → entropy, P the → pressure, and V is the final → volume. Same as the → Gibbs function and → thermodynamic potential.

Named after Josiah Willard Gibbs (1839-1903), an American physicist who played an important part in the foundation of analytical thermodynamics; → free; → energy.

gravitational energy
  کاروژ ِ گرانشی   
kâruž-e gerâneši

Fr.: énergie gravitationnelle   

Same as → gravitational potential energy.

gravitational; → energy.

gravitational potential energy
  کاروژ ِ توند ِ گرانشی   
kâruž-e tavand-e gerâneši

Fr.: énergie potentielle gravitationnelle   

1) The energy that an object possesses because of its position in a → gravitational field, especially an object near the surface of the Earth where the → gravitational acceleration can be assumed to be constant, at about 9.8 m s-2.
2) In a two body system. It is the amount of work done in bringing the mass m to the distance R from M: EP = -GMm/R, where G is the → gravitational constant.
3) For a uniform sphere. It is EP = -(3/5)GM2/R, where G is the gravitational constant and M is the mass contained in the sphere of radius R.

gravitational; → potential; → energy.

Helmholtz free energy
  کاروژ ِ آزاد ِ هلمهولتس   
kâruž-e âzâd-e Helmholtz

Fr.: énergie libre de Helmholtz   

Of a system, the quantity whose decrease gives the maximum amount of external work which is performed when any physical or chemical process is carried out reversibly at constant temperature. It is defined by F = U - TS, where U is the → internal energy, T the → absolute temperature, and S the final → entropy.

After the German physicist and physician Hermann Ludwig Ferdinand von Helmholtz (1821-1894), who made important contributions to the thermodynamics of gaseous systems; → free; → energy.

High Energy Stereoscopic System (H.E.S.S.)
  راژمان ِ استریوی ِ مه‌ کاروژ   
râžmân-e estereyo-ye meh kâruž (H.E.S.S.)

Fr.: Système stéréoscopique de haute énergie (H.E.S.S.)   

An array of → IACT telescopes for studying cosmic → gamma rays in the 100 GeV to 100 TeV energy range. The HESS observatory is located in Namibia, southern Africa, at an altitude of 1800 m, and the project is an international collaboration of more than 100 scientists from nine countries. In its Phase I, HESS used four telescopes each consisting of a light collector with a diameter of 13 m and a focal length of 15 m placed at the corners of a square 120 m apart. Each telescope is segmented into 380 round mirror facets of 60 cm diameter and uses a camera consisting of 960 closely packed → photomultiplier tubes. The first of the telescopes went into operation in Summer 2002. Phase II includes a fifth telescope, called Large Cherenkov Telescope (LCT), of 27 m diameter, located in the centre of the initial array. This upgrade lowers the triggering threshold of the HESS array to about 20 GeV, thus broadening the energy window in which gamma-ray astronomy can be done, opening up more opportunities in astrophysical research (see, e.g., Bernlöhr et al. 2003, Astroparticle Physics 20, 111).

H.E.S.S., short for High Energy Stereoscopic System, is also intended to pay homage to Victor F. Hess (1883-1964), an Austrian-American physicist who received the Nobel Prize in Physics in 1936 for his discovery of → cosmic rays.

high-energy astrophysics
  اخترفیزیک ِ مه‌کاروژ   
axtarfizik-e meh-kâruž

Fr.: astrophysique des hautes énergies   

A branch of astrophysics that deals with objects emitting highly energetic radiation, such as X-ray astronomy, gamma-ray astronomy, and extreme ultraviolet astronomy, as well as neutrinos and cosmic rays.

high; → energy; → astrophysics.

high-energy cosmic rays
  پرتوهای ِ کیهانی ِ مه‌کاروژ، ~ ~ پرکاروژ   
partowhâ-ye keyhâni-ye meh-kâruž, ~ ~ por-kâruž

Fr.: rayons cosmiques de hautes énergies   

Cosmic rays which typically have energies in the range 1015 to 1020 electron volts. For the most part, they are protons and other atomic nuclei, and come from distant cosmos, perhaps even from outside our own Galaxy.

high; → energy; → cosmic; → ray.

high-energy neutrino
  نوترینو‌ی ِ مه‌کاروژ   
notrino-ye meh-kâruž

Fr.: neutrino haute énergie   

A neutrino produced in high-energy particle collisions, such as those occurring when → cosmic rays strike atoms in the Earth's → atmosphere. Their energy range expands from a few → MeVs up to tenths of a → peta- (P) → electron-volts.

high; → energy; → neutrino.

internal energy
  کاروژ ِ درونی   
kâruž-e daruni

Fr.: énergie interne   

The difference between the energy added to a system and the energy given up by the system in performing work.

internal; → energy.

ionization energy
  کاروژ ِ یونش   
kâruž-e yoneš

Fr.: énergie d'ionisation   

Same as → ionization potential.

ionization; → energy.

kinetic energy
  کاروژ ِ جنبشی   
kâruž-e jonbeši

Fr.: énergie cinétique   

The energy which a body possesses as a consequence of its motion, defined as one-half the product of its mass m and the square of its speed v, i.e. 1/2 mv2.

kinetic; → energy.

lattice energy
  کاروژ ِ جاره   
kâruž-e jâré

Fr.: énergie réticulaire   

The energy required to separate an ion from a → crystal to an infinite distance. In other words, the energy released when one → mole of a crystal is formed from gaseous ions.

lattice; → energy.

low-energy neutrino
  نوترینو‌ی ِ کم‌کاروژ   
notrino-ye kamkâruž

Fr.: neutrino faible énergie   

A neutrino which is mainly produced in → nuclear processes, such as the ones in the → Sun (→ solar neutrino), or in the center of an exploding → supernova. Such neutrinos are, however, more energetic than those making up the → cosmic neutrino background.

low; → energy; → neutrino.

magnetic energy
  کاروژ ِ مغناتیسی   
kâruž-e meqnâtisi

Fr.: énergie magnétique   

The energy stored in a magnetic field. It is the → work that must be done to establish a magnetic field in terms of the → magnetic induction. Magnetic energy varies as the square of the magnetic induction. It can be expressed in several other ways, for example in terms of the current and of the magnetic flux, or in terms of the current density and vector potential.

magnetic; → energy.

mass energy
  کاروژ ِ جرم   
kâruž-e jerm

Fr.: énergie de masse   

The energy (E) associated with a mass (m), as specified by the → mass-energy equivalence  E = mc2, where c is the → speed of light. For a moving body the total energy of the particle is expressed by: E2 = m2c4 + p2c2, where m is → rest mass and p → momentum.

mass; → energy.

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