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: 12934 Search : far
meson
  مسون   
meson

Fr.: méson   

A nuclear particle with a mass intermediate between that of a proton and an electron, which is believed to be responsible for the strong nuclear force. In contrast to the case of baryons or leptons, meson number is not conserved: like photons, mesons can be created or destroyed in arbitrary numbers. Their charge can be positive, negative, or zero.

From mes-, meso-, from Gk. mesos "middle," akin to L. medius, Pers. miyân, → medium, → middle, + -on a suffix used in the names of subatomic particles.

mesosiderite
  مسوسیدریت   
mesosiderit

Fr.: mesosidérite   

A class of → meteorites that is → brecciatedstony-iron with nearly equal amounts of → metal and → silicates.

meso-; → siderite.

mesosphere
  مسوسپهر   
mesosepehr

Fr.: mésosphère   

The layer of the atmosphere located between the → stratosphere and the → ionosphere, where temperature drops rapidly with increasing height. It extends between 17 to 80 kilometers above the Earth's surface.

meso-; → sphere.

message
  پیام   
payâm (#)

Fr.: message   

1) General: A piece of information (written, spoken, or by signals).
2) Computer science: A defined amount of information, coded or not, between machines or machines and men. → information theory.

M.E., from O.Fr. message "message, news, embassy," from M.L. missaticum, from L. missus "a sending away, dispatching," from mittere "to send," → mission.

Payâm, variants payqâm, peyqâm, Mid.Pers. paygâm, ultimately from *patigam-, literally "arriving, newcomer," from *pati- "to, toward, at, in," → ad hoc, + *gam- "to come," → heliosheath.

Messier catalog
  کاتالوگ ِ مسیه   
kâtâlog-e Messier

Fr.: catalogue de Messier   

A catalog of more than 100 nebulous-appearing astronomical objects, initially established to avoid confusion with comets. These objects are now well known to be among the brightest and most striking gaseous nebulae, star clusters, and galaxies. The designations of the catalog are still used in identification; e.g. M1 is the Crab Nebula (in Taurus).

In honor of the French astronomer Charles Messier (1730-1817), who compiled the list between 1760 and 1784 in order to avoid confusion with comets; → catalog.

Messier object
  بر‌آخت ِ مسیه   
barâxt-e Messier

Fr.: objet de Messier   

Any of the nebulous-looking → astronomical objects listed in the → Messier catalog.

Messier catalog; → object.

Mestel theory
  نگره‌ی ِ مستل   
negare-ye Mestel

Fr.: théorie de Mestel   

The first quantitative model showing that the energy of → white dwarfs is the leftover heat from the star's past nuclear fusion that leaks slowly into space. In this analytic model constructed by Mestel (1952), a white dwarf consists of two layers. The inner layer, which contains most of the mass, is assumed to be → isothermal because of efficient thermal conductivity by the → degenerate electrons. Moreover, it is supposed that the electrons do not contribute significantly to the → heat capacity. The heat capacity comes entirely from the ions, which are assumed to behave as a classical → ideal gas. The thin non-degenerate outer layer forms an insulating blanket and controls the rate at which the energy from the ion reservoir is leaked out into space. The specific rate is controlled by the radiative opacity at the boundary between these two layers, and is assumed to obey → Kramers' opacity law. The Mestel theory shows that the cooling rate of a white dwarf is proportional to its temperature (hotter white dwarfs cool faster), and gives a relationship between the luminosity (L) of the white dwarf and the cooling time: t ∝ L-5/7. More recent models take into account some or all of the following processes neglected in the Mestel theory: neutrino cooling (important for L > 10-1.5 Lsun), latent heat of crystallization release (important for L < 10-4 Lsun), nuclear energy generation via proton-proton burning (important when MH ≥ 10-4 M*), and gravitational energy release from surface layers. The Mestel theory is a very good approximation of more recent calculations. For a review of the Mestel theory see Van Horn (1971, IAU Symp. 42, 97; W. J. Luyten, Editor), Wood (1990, J. Roy. Astro. Soc. Canada 84, 150), and Kepler and Brdaley (1995, Baltic Astron. 4, 166).

Named after Leon Mestel (1927-), British astrophysicist, who put forward this theory in 1952 (MNRAS, 112, 583); → theory.

Meszaros effect
  اسکر ِ مسزاروس   
oskar-e Meszaros

Fr.: effet de Meszaros   

Reduced growth or stagnation undergone by → cold dark matter perturbations during the period when the → early Universe was → radiation-dominated. The photons cannot collapse, and by their pressure prevent the matter to do so, when radiation dominates. Matter pertubation (collapse) remains frozen until the density equality between radiation and matter.

Péter Mészáros, 1974, A&A 37, 225; → effect.

meta-
  مَتا-   
matâ- (#)

Fr.: méta-   

A prefix appearing in loanwords from Gk., with the meanings 1) "after, behind;" 2) "changed, altered;" 3) "higher, beyond." → metagalaxy; metaphysics; → metastable.

From Gk. meta (prepositin) "in the midst of, among, with, after," originally me-ta (Mycenaean Greek), from PIE *me- "in the middle" (cf. Goth. miþ, O.E. mið "with, together with, among," E. with).

Matâ-, from Av. matay-, mati- "protrusion of mountain range," framanyente "to be protruding, jutting;" from PIE base *men- "to stand out, to project;" cf. L. mons (genitive montis) "mountain," minere "to project, jut, threaten" (other related terms: mouth, prominent, amount, etc.).

metadata
  متا-داده‌ها   
matâ-dâdhâ

Fr.: métadonnées   

Specifically defined data elements that describe how and when a particular set of data was collected, and how it is formatted. Metadata is used to organize, manipulate, and work with data when it is not necessary or desired to actually deal with the data itself. The reason is that the metadata is usually far smaller and easier to work with than the data that it represents.

meta-; → data.

metagalaxy
  مَتا-کهکشان   
matâ-kahkešân

Fr.: métagalaxie   

An obsolete term which once denoted the entire system of galaxies including the Milky Way.

meta-; → galaxy.

metal
  فلز   
felez (#)

Fr.: métal   

1) Chemistry: An → element in which the highest occupied energy band (→ conduction band) is only partially filled with electrons.
2) Astrophysics: Conventionally, any element heavier than → helium. The term "metal," as used for this concept, is in fact inappropriate. Same as → heavy element. See also → metallicity.

From O.Fr. metal, from L. metallum "metal, mine, quarry, what is got by mining," from Gk. metallon "metal, ore," originally "mine, quarry, pit," probably from metalleuein "to mine, to quarry," of unknown origin, but related somehow to metallan "to seek after."

Felez "metal," loanword from Ar. filizz.

metal deficiency
  کم‌فلزی   
kamfelezi

Fr.: déficience en métaux   

The quality of being metal deficient, e.g. → metal-deficient galaxy.

metal; deficiency from L. deficientem (nominative deficiens), pr.p. of deficere "to desert, fail," from → de- "down, away" + facere "to do, perform" + -ency a noun suffix, equivalent to -ence.

Kamfelezi, from kam "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few," related to keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") + felezmetal + -i suffix denoting state.

metal-deficient galaxy
  کهکشان ِ کم‌فلز   
kahkešân-e kamfelez

Fr.: galaxie pauvre en métaux   

A galaxy whose → metallicity is smaller than that of the → Milky Way galaxy.

Adj. from → metal deficiency; → galaxy.

metal-poor
  کم‌فلز   
kamfelez

Fr.: pauvre en métaux   

Describing an → astronomical object in which the → chemical abundances of → heavy elements are lower than that of a reference value (usually solar or of Milky Way).

metal; → poor.

metal-poor galaxy
  کهکشان ِ کم‌فلز   
kahkešân-e kamfelez

Fr.: galaxie pauvre en métaux   

Same as → metal-deficient galaxy.

metal; → poor; → galaxy.

metal-rich environment
  پرگیر ِ پرفلز   
pargir-e porfelez

Fr.: environnement riche en métaux   

An environment (→ galaxy, → nebula) whose → metallicity is larger than that of the → Milky Way galaxy.

metal; → rich; → environment.

metal-rich star
  ستاره‌ی ِ پرفلز   
setâre-ye porfelez

Fr.: étoile riche en métaux   

A star whose → metal content is higher than the → solar metallicity. The stars that harbor → extrasolar planets tend to be considerably more metal-rich than the average → Population I star in the Galactic neighborhood. See also → super-metal-rich star.

metal; → rich; → star.

metalanguage
  متا-زبان   
matâ-zabâb

Fr.: métalangue   

Any language that is used to describe a language. See also → object language.

meta-; → language.

metallic
  فلزی   
felezi (#)

Fr.: métallique   

Of, relating to, or consisting of metal.

metal; → -ic.

<< < -es -iv -ti 217 A s abe abs abs acc acc Ach act act ADa adi adv aff age Alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg arm art ass ast ast ast atm ato att aur aut axi B-t Bai Bal bar bar Be bed Bes BHB bif bim bin Bio bis bla ble blu bod Bol bor bou bra Bre bro Bul cag cal can Can car Car Cas cat CCD cel cen Cet cha cha che che chr cir cir cit cla clo clo clu Coa coe coh col Col col com com com com com com com com com con con con con con con con con con con con coo cor cor cor Cos cos cos cou cou cra cri cro cry cum cur cyc d'A dar dat DB dea dec dec dec def def deh del den dep des det deu dia dif dif dif dim dip Dir dis dis dis dis dis div dom dou dou dri duo dus dyn dyn ear eas ecl Edd eff Ein eje ele ele ele ele ell emb emi enc ene ent eph equ equ equ eru eth Eul eve ewe exc exc exi exo exp ext ext ext fab fal far fec Fer fer fie fin fir fis fla Flo flu fog for for Fou fra fre Fre fro fus G t gal gal Gam gas Gau Gem gen geo geo geo gia gla God gra gra gra gra Gre Gre gue GZK Haf hal har har He hea hel hel Her Her hid hig hip hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima imp imp imp inc ind ind ine inf inf inf ini ins ins int int int int int int int int inv inv ion iro Isl iso iso Jac jet jud jur Kel Kep kil Klo kur Lag lam Lap Lar lat law lea len lep lib lig Lin lin lin liq lit loc log lon Lor low lum lun Lut Lyo mac mag mag mag Mag mag maj man Mar mas mas mat May mea mec mel mer mes met met met mic mid mil min mir mix mod mol mom Moo mos Mu mul mus nad nas nat neb neg net neu New New nig Noe non non non nor nuc nuc nul nut Obe obl obs occ Oct off old one ope opp opt opt orb ord org Ori osc oth ova oxi P-w pal par par par par Pas pat pej per per per per per per pha phi pho pho pho phy pin Pla pla pla pla pla plu Poi pol pol pol poo pos pos pot pra pre pre pre Pre pri pri pro pro pro pro pro pro pro pse pul Pur qua qua qua qua que rad rad rad rad rad rad raf ran rar ray rea rea rec rec red red ref ref reg rel rel rel rep res res res res ret rev ric rig rin roc ROS rot Rox rus Sad sam sat sca sca Sch sci sea sec sec see sel sem sen ser Sgr sha shi sho sid sig sim sin Sir ske sli Smo soc sol sol sol Sol Som sou spa spa spe spe spe sph spi spi Spo squ sta sta sta sta Ste ste ste Sto str str str sub sub suc sun sup sup sup sup sur Swa syn syn tac tas tel tem ter tes the the the the Tho thr tid tim tit top tot tra tra tra tra tre tri Tro tru tun tut Tyn typ ult unb und uni uni uns ups Urv vag van vec vei Ven ver Vic Vir vir vis vol W b war wav wav wea wee Wey Wid win WN2 Wol wro XMM YOR zen zir > >>