An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 657
Mirândâ (#)

Fr.: Miranda   

The eleventh of Uranus's known satellites and the innermost of Uranus' large moons. Its is about 470 km in diameter and orbits Uranus at about 130,000 km from its planet. It was discovered by Kuiper in 1948.

Miranda is a daughter of the magician Prospero in Shakespeare's The Tempest.

Mirfak (α Persei)
Merfaq (#)

Fr.: Mirfak   

The brightest star of Perseus, with a visual magnitude of 1.8. It is a giant of spectral type F5 lying some 590 light-years away.

From Ar. al-Mirfaq (المرفق) "the elbow."

Merfaq, from Ar. al-Mirfaq, as above.

âyené (#)

Fr.: miroir   

A smooth, highly polished surface, for reflecting light, that may be plane or curved. The actual reflecting surface is usually a thin coating of silver or aluminum on glass.

From O.Fr. mireor "a reflecting glass," earlier miradoir, from mirer "look at," from V.L. *mirare, from L. mirari "to wonder at, admire."

Âyené, from Mid.Pers. êwênag "mirror," from *âdênak, from Proto-Iranian *ādayanaka-, from prefix ā- + the root of Av. dā(y)- "to see," didāti "sees" (cf. Mod.Pers. didan "to see," Mid.Pers. ditan "to see, regard, catch sight of, contemplate, experience;" O.Pers. dī- "to see;" Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen") + suffix -ak.

mirror blank
  گرده‌ی ِ آینه   
gerde-ye âyené

Fr.: disque miroir   

The material on which the reflecting coating is applied. It may be glass, quartz, or metal.

mirror; blank "a piece of metal ready to be drawn, pressed, or machined into a finished object," from M.E., from O.Fr. blanc (adj.) from Gmc; cf. O.E. blanca "white horse," O.H.G. blanch "bright, white."

Gerdé, → disk; âyené, → mirror.

mirror disk
  گرده‌ی ِ آینه   
gerde-ye âyené

Fr.: ébauche de miroir   

Same as → mirror blank.

mirror; → disk.

mirror testing
  آزمون ِ آینه   
âzmun-e âyené (#)

Fr.: test d'un miroir   

The observation and measurement of the flatness of a mirror surface. The process generally is done before coating so as not to damage the delicate coated surface. For coated and curved surfaces, non-contact methods are often employed, generally using interference techniques.

mirror; → test.

Mirzam (β Canis Majoris)
Merzam (#)

Fr.: Mirzam   

The fourth brightest star in the constellation → Canis Major. It is a B1 → giant of magnitude 2.0 lying about 500 → light-years away. Mirzam is one of the brightest of the → Beta Cephei variable stars.

From Ar. al-Mirzam (المرزم) "subordinate," which according to the Persian astronomer Biruni (A.D. 973-1048) was a general name for a relatively fainter star lying beside a much brighter one, in this case → Sirius. Some sources have related the name of this star to Ar. al-Murzim (المرزم) "the roarer." They claim that this name refers to the fact that the star is situated to the east of Sirius and thus "announces, heralds" imminent rising of Sirius. However, this interpretation does not seem tenable since the meaning "announcing" is far-fetched, and moreover the angular distance between Sirius and Mirzam being small, they actually rise together.


Fr.: mésalignement   

Deviation of the chain of → optical components from the optimum → alignment in an instrument which leads to → loss of → light and poor → image.

From mis- a prefix meaning "ill, mistaken, wrong, wrongly" + → alignment.

Dožxateš, from dož-, → dys-, + (â)xateš, → alignment.

mušak (#)

Fr.: missile   

An object or weapon for throwing, hurling, or shooting. → ballistic missile.

From Fr. missile, from L. missile "weapon that can be thrown," from missus, p.p. of mittere "to send."

Mušak, literally "little mouse," or "mouse like," from a firework explosive that was likened to a mouse, from muš, → mouse, + -ak diminutive or similarity suffix.

missing mass
  جرم ِ گم‌شده   
jerm-e gomšodé (#)

Fr.: masse manquante   

The unseen mass whose gravitational influence is needed to account for the way galaxies rotate, and also to bind clusters of galaxies together. It is thought to consist, in part, of giant halos of dark matter that surround the visible portions of galaxies, and similar material that invisibly occupies the intergalactic voids. Same as → hidden mass; → dark matter.

Missing, from miss "to fail to be present," from M.E. missen, O.E. missan; cf. O.Fris. missa, M.Du. missen, Ger. missen "to miss, fail;" → mass.

Jerm, → mass; gomšodé "lost, missing," from gom "missing, lost" + šodé p.p. of šodan "to become" (from Mid.Pers. šudan, šaw- "to go;" Av. šiyav-, š(ii)auu- "to move, go," šiyavati "goes," šyaoθna- "activity; action; doing, working;" O.Pers. šiyav- "to go forth, set," ašiyavam "I set forth;" cf. Skt. cyu- "to move to and fro, shake about; to stir," cyávate "stirs himself, goes;" Gk. kinein "to move;" Goth. haitan "call, be called;" O.E. hatan "command, call;" PIE base *kei- "to move to and fro").

missing satellites problem (MSP)
  پراسه‌ی ِ بنده‌وارهای ِ گم‌شده   
parâse-ye bandevârhâ-ye gomšodé

Fr.: problème des satellites manquants   

The observed underabundance, by one or two orders of magnitude, of → dwarf galaxies orbiting → spiral galaxies compared to their number predicted by the standard model. The → cold dark matter (CDM) model predicts that dwarf galaxies are the building blocks of large galaxies like the Milky Way and should largely outnumber them. Dwarf galaxies form first, they merge into bigger and bigger galaxies, and galaxies into groups of galaxies. The dark matter halos, however, are very dense, and dwarf halos are not destroyed in the merging, resulting in their large predicted number, in numerical simulations.

Probably first dealt with in an article entitled "Where Are the Missing Galactic Satellites?" (Lypin et al. 1999, ApJ 522, 82); → missing mass; → satellite; → problem.


Fr.: mission   

An operation designed to carry out the goals of a specific program, such as a a space flight or voyage.

Mission, from L. missionem (nominative missio) "act of sending," from mittere "to send," of unknown origin.

Gosilân, from gosil, variant gosi "sending away, dismission;" Mid.Pers. wisé "to despatch" (Parthian Mid.Pers. wsys- "to despatch;" Buddhist Mid.Pers. wsydy "to despatch;" Sogdian 'ns'yd- "to exhort"), from Proto-Iranian *vi-sid- "to despatch, send off," from prefix vi- "apart, away, out," + *sid- "to call" + -ân nuance suffix.


Fr.: brume   

A very thin fog consisting of an aggregate of microscopic water droplets or wet hygroscopic particles (of diameter not less than 0.5 mm), in which the visibility at the earth's surface is greater than 1 km.

O.E. mist "dimness, mist," from P.Gmc. *mikhstaz (cf. M.L.G. mist, Icelandic mistur), from PIE *migh-/*meigh-; cf. Pers. miq "fog, mist;" Gk. omikhle, O.C.S. migla, Skt. megha- "cloud, mist." → nebula.

Nezm "mist, fog," variants nezu, nezvâ "mist," nam "moisture, humidity;" Av. napta- "moist," nabās-câ- "cloud," nabah- "sky;" cf. Skt. nábhas- "moisture, cloud, mist;" Gk. nephos "cloud, mass of clouds," nephele "cloud;" L. nebula "mist," nimbus "rainstorm, rain cloud;" O.H.G. nebul; Ger. Nebel "fog;" O.E. nifol "dark;" from PIE *nebh- "cloud, vapor, fog, moist, sky."

âmixtan (#)

Fr.: mélanger   

To combine (substances, elements, things) into one mass, collection, or assemblage, generally with a thorough blending of the constituents.

From M.E. myxte, from O.Fr. mixte, from L. mixtus, p.p. of miscere "to mix;" cognate with Pers. âmixtan, âmiz-, as below; from PIE *meik- "to mix."

Âmixtan, âmizidan "to mix," from Mid.Pers. âmêz-, âmêxtan (Proto-Iranian *āmis- ,*āmiz-; PIE *meik- "to mix"); cf. Av. mayas- "to mix;" Skt. miks- "to mix, mingle," miśr- "to mix, blend, combine;" Gk. misgein "to mix, mingle;" L. miscere (p.p. mixtus) "to mix;" O.C.S. meso, mesiti "to mix," Rus. meshat, Lith. maisau "to mix, mingle."

mixed merger
  تشک ِ آمیخته   
tašk-e âmixté

Fr.: fusion mixte   

A merger that takes place when a → gas-poor galaxy collides with a → gas-rich galaxy.

Past-participle of → mix; → merger.


Fr.: mélangeur   

In the → superheterodyne technique, the electronic component that lowers the frequency of the input signal and combines it with the signal coming from the → local oscillator to produce the → intermediate frequency signal. The lowered frequency, when amplified, has little chance to escape back into the antenna and produce feedback. Moreover, it is easier to make efficient amplifiers, filters, and other components for lower frequencies.

Agent noun from → mix.

âmizeš (#)

Fr.: mélange   

1) General: The process or result of irregular fluctuations in fluid motions on all scales from the molecular to large eddies.
2) Stellar interior: A process whereby → angular momentum and chemical species are transported from layer to layer within a star. The main mixing processes include: → convection, → overshooting, → rotation, → turbulence. The extent to which the interiors of stars are mixed strongly influences their evolution, age, chemical content, and the relationship between their internal and surface abundances.

Verbal noun of → mix.

mixing length
  درازای ِ آمیزش   
derâzâ-ye âmizeš

Fr.: longueur de mélange   

In a → turbulent flow, the average distance traveled by a → convective cell before it dissolves into its surroundings and deposits its energy. The mixing length is of the order of the → pressure scale height (HP), l = αHP, where α is the → mixing length parameter. See also → mixing length theory.

mixing; → length.

mixing length parameter
  پارامون ِ درازای ِ آمیزش   
pârâmun-e derâzâ-ye âmizeš

Fr.: paramètre de la longueur de mémange   

In the → mixing length theory, a parameter, α, that relates the → mixing length, l, to the → pressure scale height: α = l/HP. It is usually supposed that α is of order unity. Changes in α correspond to variations in the efficiency of the → convection, hence the transfer of heat.

mixing; → length; → parameter.

mixing length theory (MLT)
  نگره‌ی ِ درازای ِ آمیزش   
negare-ye derâzâ-ye âmizeš

Fr.: théorie de la longueur de mélange   

A theory dealing with heat transport by → turbulence which includes an elementary treatment of → convection. The central idea is that an unbalanced → buoyancy force drives a → convective cell to move through a distance, called the → mixing length, before the cell dissolves and joins the ambient medium. In this theory an adjustable → mixing length parameter  α is used. The theory, originally due to L. Prandtl (1925), was first applied to the Sun by L. Biermann (1932, Z. Astrophys. 5, 117).

mixing; → length; → theory.

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