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: 672
microturbulence
  ریز‌آشوبناکی   
riz-âšubnâki

Fr.: microturbulence   

The → turbulence phenomenon involving relatively smaller physical volumes compared to → macroturbulence. In stellar atmospheres, it is a bulk gas motion with a characteristic size less than the local photon → mean free path. Microturbulence is one of the most significant mechanisms that can cause → line broadening in the stellar spectrum. The presence of microturbulence de-saturates strong lines and increases their → equivalent widths. Microturbulence in → hot stars brings about gas motions with velocities 0-20 km s-1. A physical connection may exist between microturbulence in hot star atmospheres and a subsurface → iron convection zone. Microturbulence may also be at the origin of → wind clumping in hot stars.

micro-; → turbulence.

microwave
  ریزموج   
rizmowj (#)

Fr.: micro-onde   

Electromagnetic radiation having wavelengths in the 1 to 300 mm range.

micro-; → wave.

microwave background radiation
  تابش ِ پس‌زمینه‌ی ِ ریزموج   
tâbeš-e paszamine-ye rizmowj

Fr.: rayonnement micro-onde du fond cosmique   

Thermal radiation with a temperature of 2.73 K that is apparently uniformly distributed in the Universe. It is believed to be a redshifted remnant of the hot radiation that was in thermal equilibrium with matter during the first hundred thousand years after the Big Bang. Same as → cosmic microwave background (CMB) radiation.

microwave; → background; → radiation.

microwave radiation
  تابش ِ ریزموج   
tâbeš-e rizmowj (#)

Fr.: rayonnement micro-onde   

Electromagnetic radiation carried by → microwaves.

microwave; → radiation.

mid-
     
miyâni-; nim-, nimé (#)

Fr.: mi-; moyen   

A prefix which means being at or near the middle point of; being or occupying a middle place or position.

M.E., from O.E. midd-, cognate with O.H.G. mitti, O.N. mithr, Gothic midjis, O.Ir. mide, L. medius, Gk. mesos, Skt. mádhya-, Av. maidiia- "middle, the middle," Pers. miyân, as below.

Miyâni, from miyân "within, between, center," from Mid.Pers. mayân "middle; among, between," Av. maidiia- "middle, the middle," maiδiiāna- "middle, center," maδəma- [adj.] "middle, being in the middle; middling, of a middling size or quality," maiδim "in the midst of," cf. Skt. mádhya- "middle, located in the middle;" O.H.G. mitti "located in the middle."
nim-, nimé, → half.

Mid-Atlantic Ridge
  روک ِ میان-اتلسی   
ruk-e miyân Atlasi

Fr.: dorsale médio-atlantique   

An immense chain of underwater mountains that runs down the middle of the Atlantic Ocean. The MAR, approximately 500-1000 km wide, extends 16,000 km from Iceland to the Antarctic Circle. The MAR is so high that it actually rises above sea level in many places, forming volcanic islands. The Azores, Ascension, St. Helena, and Iceland all arise from this great Atlantic range. The chain results from the movement of the continental plates. As these plates slowly separate, they leave gaps in the → Earth's crust. This allows molten rock from beneath the Earth's crust to reach the surface and forms a ridge. The MAR is a part of the global → mid-ocean ridge system.

mid-; → Atlantic; → ridge.

mid-infrared
  فروسرخ ِ میانی   
forusorx-e miyâni (#)

Fr.: infrarouge moyen   

The portion of the → electromagnetic radiation lying between the → near-infrared and the → far-infrared. This covers the wavelength range approximately from 8 to 30 → microns. See also: → infrared radiation, → submillimeter radiation.

mid-; → infrared.

mid-ocean ridge
  روک ِ میان-اقیانوسی   
ruk-e miyân-oqyânusi

Fr.: dorsale médio-océanique   

Any of submarine mountain ranges that stretch around the world through the Atlantic Ocean and across the Pacific and Indian Oceans. Such ridges generally stand about 1000 m to 3000 m above the adjacent ocean floor and are about 500-1000 km in width.

mid-; → ocean; → ridge.

midday
  نیمروز   
nimruz (#)

Fr.: midi   

The middle of the day; noon or the time centering around noon.

mid-; → day.

middle
  ۱) میان؛ ۲) میانی   
1) (n.) miyân; 2) (adj.) miyâni

Fr.: 1) milieu; 2) du milieu   

The point, part, position, etc., equidistant from extremes or limits.

M.E., O.E. middel; cf. M.L.G., Du. middel, Ger. mittel, variant mid; cognate with Pers. miyân, as below; from PIE *medhyo-.

1) Miyân "within, between, center," from Mid.Pers. mayân "middle; among, between," Av. maidiia- "middle, the middle," maiδiiāna- "middle, center," maδəma- [adj.] "middle, being in the middle; middling, of a middling size or quality," maiδim "in the midst of," cf. Skt. mádhya- "middle, located in the middle;" O.H.G. mitti "located in the middle."
2) From miyân + suffix -i.

middle atmosphere
  هواسپهر ِ میانی، جو ِ ~   
havâsepehr-e miyâni, javv-e ~

Fr.: atmosphère moyenne   

The region lying between the → troposphere and the → thermosphere comprising the → stratosphere and the → mesosphere (Meteorology Glossary, American Meteorological Society).

middle; → atmosphere.

middle infrared
  فروسرخ ِ میانی   
forusorx-e miyâni (#)

Fr.: infrarouge moyen   

Same as → mid-infrared.

middle; → infrared.

middle latitudes
  وَروناهای ِ میانی   
varunâhâ-ye miyâni

Fr.: latitudes moyennes   

The latitude belt roughly between 35 and 65 degrees North and South. Also referred to as the temperate region.

middle; → latitude.

middle term
  ترم ِ میانی   
tarm-e miyâni

Fr.: moyen terme   

Logic: In a → syllogism, the categorical term occurring in both the → major term and the → minor term.

middle; → term.

midnight
  نیمشب   
nimšab (#)

Fr.: minuit   

Generally, the middle of the night as indicated by twelve o'clock at night.
True midnight: The time when the Sun is closest to nadir and the night is equi-distant from dusk and dawn. The opposite of noon.

From mid- an E. combining form related to → middle; → night.

Nimšab, from nim "mid-, half" (Mid.Pers. nêm, nêmag "half;" Av. naēma- "half;" cf. Skt. néma- "half") + šab, → night

midnight Sun
  خورشید ِ نیمشب   
xoršid-e nimšab (#)

Fr.: Soleil de minuit   

The phenomenon occurring when the Sun is visible above the horizon at midnight. This phenomenon can be seen at positions north of the Arctic Circle and south of the Antarctic Circle when the Sun is circumpolar (around the summer solstice in the northern hemisphere and the winter solstice in the southern hemisphere respectively).

midnight, → sun.

Mie scattering
  پراکنش ِ می   
parâkaneš-e Mie

Fr.: diffusion de Mie   

The scattering of → electromagnetic waves by → particles of → size comparable to the radiation → wavelength. Mie scattering depends weakly upon the wavelength, hence the → scattered light spectrum is similar to that of the → incident light. Mie scattering explains the → white color of clouds when scattering is due to → water droplets having a size of few microns. Cloud → droplets with a diameter of around 20 microns or so are large enough to scatter all visible wavelengths more or less equally. Because all wavelengths are scattered, clouds appear to be white. When clouds become very deep, less and less of the incoming solar radiation makes it through to the bottom of the cloud, which gives these clouds a darker appearance.

Named after Gustav Adolf Mie (1868-1957), a German physicist, whose theory of 1908 explains the process; → scattering.

Mie theory
  نگره‌ی ِ می   
negare-ye Mie

Fr.: théorie de Mie   

The explanation of the → scattering of → electromagnetic waves by → homogeneous spheres of arbitrary → size and → composition using analytical solutions of → Maxwell's equations. See also: → Mie scattering, → Rayleigh scattering.

Mie scattering; → theory.

migrate
  موژیدن   
mužidan

Fr.: émigrer, immigrer   

1) To go from one country, region, or place to another.
2) To pass periodically from one region or climate to another, as certain birds, fishes, and animals.
3) Chem.: To move toward an electrode during electrolysis; (of atoms within a molecule) to change position (Dictionary.com).

From L. migratus p.p. of migrare "to move from one place to another," ultimately from PIE *meigh- "to move, go;" cf. Gk. ameibein "to change," Iranian muž-, as below.

Mužidan, ultimately from Proto-Ir. *maij- "to move (to places);" cf. Parachi muž-, muš-, Yazghulami mûž- "to go," mexw-/maxwt- "to move, shake," Gilaki maxtan "to stroll," Gonâbâdi mejon "ague, shivering, shaking chills," Sangesari moj; cognate with L. migrare "to move, go," as below, Skt. niméghanāna- "moving down;" PIE *meigh- "to move, eo."<.p6

migration
  موژش، کوچ   
mužeš, kuc (#)

Fr.: migration   

1) The process or act of migrating; a migratory movement.
2) For an astronomical body, the process or act of changing its place over considerably large distances under the effect of certain physical forces. See, for example, → orbital migration; → Type I migration; → Type II migration.
3) Chem.: A movement or change of position of atoms within a molecule (Dictionary.com).

migrate; → -tion. Kuc "the act of moving from a dwelling, a place to another, decamping, migration."

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