An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

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.

Spell a word wrongly.

→ mis-; → spell.

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."

A → glove that leaves the lower ends of the fingers bare, especially a long one made of lace or other fancy material and worn by women (Dictionary.com). → mitten.

→ mitten.

Dastpuš, from dast, → hand, + puš present stem of pušidan "to cover, to put on," → envelope.

A hand covering enclosing the four fingers together and the thumb separately (Dictionary.com). → glove, → mitt.

M.E. miteyn, from M.Fr., O.Fr. mitaine, from from O.Fr. mite "mitten," and from M.L. mitta.

Dasmtuž, literally "hand-shoe" (Ger. Handschuh, "glove," literally "hand-shoe"), from dast, → hand, + Muž, variant of Pers. muzé "shoe," Mid.Pers. môg "shoe, boot;" cf. Pers. paymôz- / paymôxtan "to dress;" Av. (+ pati-paitišmaoc- "to shoe;" Proto-Ir. *(h)mauc-? "to dress, clothe" (Cheung 2007).

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."

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

Past-participle of → mix; → merger.

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.

1) General: The process or result of irregular fluctuations in fluid motions on all scales from the molecular to large eddies.
2) Relating to → stellar interior, → mixing process.

Verbal noun of → mix.

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 (H_P), l = αH_P, where α is the → mixing length parameter. See also → mixing length theory.

→ mixing; → length.

In the → mixing length theory, a parameter, α, that relates the → mixing length, l, to the → pressure scale height: α = l/H_P. 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.

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.

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, and → 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 → chemical abundances.

→ mixing; → process.

Mass of water vapor per mass of dry air; expressed as grams per kilogram. → humidity

→ mixing; → ratio.

An aggregate of two or more substances that are not chemically combined with each other.

M.E., from L. mixtura "a mixing," from mixtus, → mix.

Âmizé, from âmiz present stem of âmixtan, → mix.

A star of visual magnitude 2.3 in the constellation → Ursa Major, which is the second star from the end of the → Big Dipper's handle. It forms a naked-eye double with → Alcor, lying at an angular separation of about 12 minutes of arc. Mizar is resolved into a 14''.4 → binary star (denoted A and B) with a probable period of thousands of years. Mizar A is a nearly equal-mass, → double-lined spectroscopic binary with period 20.54 days and → eccentricity of 0.53. The two components of Mizar A (denoted Aa and Ab) are both about 35 times as luminous as the Sun, and revolve around each other in about 20 days. Similarly, Mizar B is a → spectroscopic binary with a period of 175.57 days and an eccentricity of 0.46. Recent results suggest that Alcor is actually a binary and apparently → gravitationally bound to the Mizar system. This would make the Mizar-Alcor system a probable → sextuplet, lying at about 78 → light-years from Sun and the second closest such multiple known, after → Castor (Mamajek et al., 2010, AJ 139, 919).

Mizar, from Ar. al-Mi'zar (المءزر) "loin cloth, apron, veil."

A unit of → radio flux density, equal to 10^-3 → jansky (Jy).

→ milli-; → jansky (Jy).

A system of stellar → spectral classification. The same as → Morgan-Keenan classification. Also called MKK system, → Yerkes system.

→ Morgan-Keenan classification.

The system of → MKS units.

→ MKS unit; → system.

The international system of units based on the → meter, → kilogram, and → second.

MKS, the initials of → meter, → kilogram, and → second; meter, kilogram, and second; → unit.