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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<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir 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 Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>

Number of Results: 12948 Search : far
meridional
  نیمروزانی   
nimruzâni

Fr.: méridien   

Of, pertaining to, or resembling a meridian.

meridian + → -al.

From nimruzân, → meridian, + -i adj. suffix.

meridional circulation
  پرهونش ِ نیمروزانی   
parhuneš-e nimruzâni

Fr.: circulation méridien   

The mass motion of material within a → rotating star generated by the star's departure from spherical symmetry. For a rotating star in which → centrifugal forces are not negligible, → radiative equilibrium and → hydrostatic equilibrium cannot be satisfied. In this condition energy transfer is accomplished by means of the physical motion of material. According to → von Zeipel theorem, the heating on an → equipotential surface is generally higher in the polar direction than in the equatorial direction, which drives a large scale circulation current rising at the pole and descending at the equator. As a consequence, → mixing of material takes place in the stellar interior; see also → Eddington-Sweet time scale. The meridional circulation plays an important role in the evolution of → massive stars. The circulation current was first suggested by Arthur S. Eddington in 1926 (The Internal Constitution of the Stars, Dover Pub. Inc., New York) and subsequently quantified by P. A. Sweet (1950, MNRAS 110, 548).

meridional; → circulation.

meridional flow
  تچان ِ نیمروزانی   
tacân-e nimruzâni

Fr.: courant méridien   

Meteo.: A flow between the poles, or between the equator and the poles. A positive value indicates flow away from the equator; a negative value, flow toward the equator.

meridional; → flow.

meridional magnetic field
  میدان ِ مغناتیسی ِ نیمروزانی   
meydân-e meqnâtisi-ye nimruzâni

Fr.: champ magnétiquue méridien   

In the → solar dynamo model, a magnetic field that points from the north to south or south to north.

meridional; → magnetic; → field.

Merope
  مروپه   
Meropé (#)

Fr.: Mérope   

One of the stars in the Pleiades with a visual magnitude 4.17. It is a giant of spectral type B6 lying at a distance of about 1400 light-years.

Merope was one of the seven Pleiades, daughters of the Titan Atlas.

Mersenne prime
  نخست ِ مرسن   
naxost-e Mersenne

Fr.: nombre de Mersenne premier   

A → prime number of the form 2p - 1, where p is a prime. As of February 2013, 48 Mersenne primes are known. The largest known prime number is 257,885,161 - 1. Each prime gives rise to an even → perfect number.

Marin Mersenne (1588-1648), French theologian, philosopher, mathematician and music theorist; → prime.

Mesarthim (γ Arietis)
  مسارتیم   
Mesârtim

Fr.: Mésarthim   

A star of visual magnitude 4.8 lying 204 light-years away in the constellation → Aries. It is in fact a triple star system.

The origin of Mesarthim (or Mesartim) is a matter of controversy. Some scholars have related it to the Ar. methartim (مثرطم) "very fat (animal)," but the connection is not obvious although the words are apparently similar. The original Ar. name was Šaratayn (الشرطین) "the two marks" denoting the current β and γ stars in Aries. It was also the name of the lunar mansion of which these two stars were members. Johann Bayer (1572-1625) erroneously related Šaratayn to the Hebrew Sartai, a current term in the astrological literature of his time. Subsequently, others figured that Sartai was related to Hebrew Mesartim "servants." The Latin transliteration and alteration Mesarthim found much success in establishing itself as the proper name for star γ Arietis.

mesh
  بانچه   
bâncé

Fr.: maille, maillage   

1) One of the open spaces between the cords or ropes of a net.
2) Any knit, woven, or knotted fabric of open texture.
3) An interwoven or intertwined structure; network.
4) Electricity: A set of branches that forms a closed path in a network so that removal of a branch results in an open path. (Dictionary.com).

M.E. mesche "open space in a net," apparently from O.E. max "net," earlier mæscre (cf. Dan. maske, Sw. maska, M.Du. maessce, Du. maas "mesh," O.H.G. masca, Ger. Masche "mesh").

Bâncé "aperture, opening, window" in (Kermânšâhi) Kurd., ultimately from Proto-Ir. *banaka-, from *baH- "to shine," cf. Av. bāmya- "light, bright;" Pers. bâm "morning, dawn; splendor, light," Ossetic bon "day," probably related to bezel "opening, aperture," in several dialects of the Fârs province (Lâr, Gerâš, Xonj, Fišvar), → morning.

meso-
  مسو-   
meso-

Fr.: meso-   

A combining form meaning "middle," used in the formation of compound words; e.g. → meson; → mesosphere.

From Gk. mesos "middle, in the middle;" akin to L. medius, Pers. miyân, → middle; → medium.

Meso-, loan from Gk.

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.

<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir 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 Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>