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
monsoon
  بادهای ِ موسمی   
bâdhâ-ye mowsemi (#)

Fr.: mousson   

A seasonal change in wind direction bringing dry air or heavy rain in India and nearby lands.

Monsoon, from Du. monssoen, from Port. monçao, from Ar. mausim "season." It was first applied to the winds over the Arabian Sea, which blow for six months from northeast and for six months from southwest, but it has been extended to similar winds in other parts of the world.

Bâd, → "wind;" mowsem, related to mowsem, from Ar. mausim, as above.

Monte Carlo Method
  روش ِ مونت‌کارلو   
raveš-e Monte Carlo

Fr.: méthode de Monte Carlo   

A computer-intensive technique that relies on repeated random sampling of a statistical population to compute its results. Monte Carlo simulation is often used for approximate numerical computations when application of strict methods requires too much calculation, or when it is infeasible or impossible to compute an exact result with a deterministic algorithm.

The term Monte Carlo was coined in the 1940s by physicists (Stanislaw Ulam, Enrico Fermi, John von Neumann, and Nicholas Metropolis) working on nuclear weapon projects in the Los Alamos National Laboratory. The name is a reference to a famous casino in Monaco which, it is said that, Ulam's uncle would borrow money to gamble at. → method.

month
  ماه   
mâh (#)

Fr.: mois   

A period of time based on the revolution of the Moon around the Earth. Several types of months are defined: → anomalistic month; → draconic month; → sidereal month; → synodic month; → tropical month.

O.E. monað, from P.Gmc. *mænoth- (O.N. manaðr, M.Du. manet, Du. maand, O.H.G. manod, Ger. Monat, Goth. menoþs "month"), related to *mænon-, → moon.

Mâh and mâng in Pers. are variants of the same term, the dominant form being mâh, while mâng (Av. from, see below) is used in classical literature as well as in some dialects: Tabari, Kurd. mâng, Laki, Tâti, Taeši mong, Šahmirzâdi, Sangesari mung; Mid.Pers. mâh "moon, month;" O.Pers. māha- "moon, month;" Av. māh- "month, moon," also māwngh-; cf. Skt. mās- "moon, month;" Gk. mene "moon," men "month;" L. mensis "month;" O.C.S. meseci, Lith. menesis "moon, month;" O.Ir. mi, Welsh mis, Bret. miz "month;" O.E. mona; E. moon, month; Ger. Mond, Monat; Du. maan; PIE base *me(n)ses- "moon, month."

Note: In Persian the same term, mâh, is used for two different, but related, concepts: moon and month. This was also the case for other IE languages, as shows the above etymology. However, other IE languages have evolved toward more accuracy by using different forms of the same initial term, as in E. moon / month or Ger. Mond / Monat. The Latin family uses two unrelated words, as in Fr. lune "moon" / mois "month" and Sp. luna / mes. An additional difficulty in present Pers. is that the adj. mâhi not only means "lunar" and "monthly" it also denotes "fish." For the sake of clarity and precision, this dictionary uses mângi for "lunar."

moon
  ماه، مانگ   
mâh (#), mâng (#)

Fr.: Lune   

1) Natural satellite of the Earth. Mass 7.35 x 1025 g = 1/81 or 0.0123 Earth's. Mean radius 1740 km = ~ 1/4 the Earth's; this relatively small size ratio makes the Earth-Moon system unique in the → solar system. Mean density 3.34 g cm-3. Mean distance from Earth 384,400 km. → Escape velocity 2.38 km s-1. → Surface gravity 162.2 cm s-2 = 0.165 Earth's. → Sidereal period 27d 7h 43m 11s. → Eccentricity 0.0549. → Inclination of → orbital plane to → ecliptic 5° 8' 43''. → Obliquity 6° 41'. → Synodic period 29d 12h 44m 2s.9. → Orbital velocity 1.02 km s-1. The Moon's average visual → Albedo is 0.12, a factor of three smaller than that of Earth. The Moon's → center of mass is displaced about 2 km in the direction of Earth. The average temperature on the surface of the Moon during the day is 107 °C. During the night, the average temperature drops to -153 °C. Studies of lunar rock have shown that melting and separation must have begun at least 4.5 x 109 years ago, so the → crust of the Moon was beginning to form a very short time after the → solar system itself. Thickness of crust ~ 60 km; of mantle ~ 1000 km. Temperature of core ~ 1500 K. It would have taken only 107 years to slow the Moon's rotation into its present lock with its → orbital period. Because of this → synchronous rotation, the Moon revolves once on its axis each time it orbits the Earth, thus always presenting the same face, the nearside, toward Earth. The Moon may have formed during a collision between the early Earth and a Mars-sized rocky planet about 4.6 billion years ago; → Theia.
2) A large body orbiting a planet.

O.E. mona, from P.Gmc. *mænon- (cf. O.S., O.H.G. mano, O.Fris. mona, O.N. mani, Du. maan, Ger. Mond, Goth. mena "moon"), cognate with Pers. mâh, as below, from PIE *me(n)ses- "moon, month."

Mâh and mâng in Pers. are variants of the same term, the dominant form being mâh, while mâng (Av. from, see below) is used in classical literature as well as in some dialects: Tabari, Kurd. mâng, Laki, Tâti, Taelši mong, Šahmirzâdi, Sangesari mung; Mid.Pers. mâh "moon, month;" O.Pers. māha- "moon, month;" Av. māh- "month, moon," also māwngh-; cf. Skt. mās- "moon, month;" Gk. mene "moon," men "month;" L. mensis "month;" O.C.S. meseci, Lith. menesis "moon, month;" O.Ir. mi, Welsh mis, Bret. miz "month;" O.E. mona; E. moon, month; Ger. Mond, Monat; Du. maan; PIE base *me(n)ses- "moon, month."

Note: In Persian the same term, mâh, is used for two different, but related, concepts: moon and month. This was also the case for other IE languages, as shows the above etymology. However, other IE languages have evolved toward more accuracy by using different forms of the same initial term, as in E. moon / month or Ger. Mond / Monat. The Latin family uses two unrelated words, as in Fr. lune "moon" / mois "month" and Sp. luna / mes. An additional difficulty in present Pers. is that the adj. mâhi not only means "lunar" and "monthly" it also denotes "fish." For the sake of clarity and precision, this dictionary uses mângi for "lunar."

Moon halo
  هاله‌ی ِ ماه   
hâle-ye mâh (#)

Fr.: halo de la lune   

Same as → lunar halo.

Moon; → halo.

Moon's age
  ۱) کهن‌روزی ِ ماه؛ ۲) سن ِ ماه   
1) kohan-ruzi-ye mâh; 2) senn-e mâh

Fr.: âge de la lune   

1) The number of days that have elapsed since the last → conjunction of the Sun and Moon. It is 7 days at → first quarter, 15 days at → full moon, and 22 days at → third quarter.
2) The time past since the → formation of the Moon.

Moon; → age.

1) Kohan-ruzi literally "age in days," from kohan-ruz "old in days," from kohan "old, ancient," kohné "worn;" Mid.Pers. kahwan "old, aged, worn;" pir; Mid.Pers. pir "old, aged, ancient;" Av. parô (adv.) "before, before (of time)," in front (of space); cf. Skt. puáh, combining form of puras "before (of time and place), in front, in advance;" mâh, → Moon.
2) Senn, → age.

Moon's apsidal precession
  پیشایان ِ هباکی ِ مانگ   
pišâyân-e habâki-ye mâng

Fr.: précession absidiale de la Lune   

The → rotation of the Moon's → orbit within the → orbital plane, whereby the axes of the ellipse change direction. The Moon's → major axis makes one complete revolution every 8.85 Earth years, or 3,232.6054 days, as it rotates slowly in the same direction as the Moon itself (direct, or → prograde motion). The Moon's apsidal precession is a → relativistic effect, and should not be confused with its → axial procession.

Moon; → apsidal; → precession.

moonbow
  ماه‌کمان   
mâhkamân

Fr.: arc en ciel lunaire   

A rainbow that arises from the refraction and reflection of moonlight on rain drops or mist.

moon; → bow.

moonlet
  مانگچه   
mângcé

Fr.: satellite mineur, lune mineure   

A very small natural or artificial satellite orbiting a planet. Saturn has dozens of moonlets often associated with its → planetary rings.

moon; → -let.

moonlet wake
  کل ِ مانگچه   
kel-e mângcé

Fr.: sillage de lune mineure   

Local disturbances in the ring structure caused by the gravitational influence of embedded satellites. If the satellite (moonlet) is large enough to clear a gap in the rings, the moonlet wakes become edge waves that precede the satellite on the inner edge and trail the satellite on the outer edge. For smaller satellites, the "gap-less" wakes have been nicknamed propellors (Ellis et al., 2007, Planetary Ring Systems, Springer).

moonlet; → wake.

moonlight
  مهتاب   
mahtâb (#)

Fr.: clair de lune   

The light of the Moon.

From → moon + → light.

Mahtâb (Gilaki mângtâb) from mah, mâh (mâng), → moon, + tâb "light," from tâbidan, tâftan "to shine," tafsidan "to become hot" (Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "to spoil, injure, damage; to suffer; to heat, be/become hot," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "warm").

moonrise
  بر‌آمد ِ ماه   
barâmad-e mâh (#)

Fr.: lever de la lune   

The times at which the apparent upper limb of the ascending Moon is on the astronomical horizon.

moon; → rise.

moonset
  فروشد ِ ماه   
forušod-e mâh (#)

Fr.: coucher de la lune   

The crossing of the visible horizon by the upper limb of the descending Moon.

moon; → set.

moonset lag
  لک ِ فروشد ِ ماه   
lek-e forušod-e mâh

Fr.: retard du coucher de la lune   

The delay between → sunset and → moonset.

moonset; → lag.

Mordor
  موردور   
Mordor

Fr.: Mordor   

A unique feature of → Pluto's large satellite → Charon. It appears as a dark reddish area about 475 km in diameter in Charon's north polar region, as revealed in → New Horizons' approach images. It has been proposed that the feature is due to gas from Pluto. A part of Pluto's → atmosphere (→ methane molecules) is transiently cold-trapped and processed at Charon's winter pole (W. M. Grundy et al., 2016, Nature, 14 September).

Unofficial name.

Moreton wave
  موج ِ مورتون   
mowj-e Moreton

Fr.: onde de Moreton   

A large-scale → shock wave observed in Hα on the Sun's → chromosphere that is generated by the impact of a → solar flare. Moreton waves expand outward at about 1,000 km/s, and may travel for several hundred thousand kilometers. They are accompanied by meter-wave radio bursts.

Named after the American astronomer Gail E. Moreton (1960, A.J. 65, 494); → wave.

Morgan-Keenan classification
  رده‌بندی ِ مورگان-کینان   
radebandi-ye Morgan-Keenan (#)

Fr.: classification de Morgan-Keenan   

A system of → spectral classification introduced in 1943 by William W. Morgan (1906-1994), Philip C. Keenan (1908-2000), and Edith M. Kellman (1911-2007) at Yerkes Observatory. Also known as the MK (or MKK) classification or the → Yerkes system.

Named after the two main astronomers, as above; → classification.

morning
  بامداد   
bâmdâd (#)

Fr.: matin   

The first part or period of the day, extending from dawn, or from midnight, to noon. Not a precise astronomical term.

From M.E. morn, morwen, from O.E. margen earlier morgen (cf. O.H.G. morgen, Goth. maurgins) + → -ing.

Bâmdâd, from Mid.Pers. bâmdâd"morning, dawn," from bâm "beam of light, splendor," bâmik "brilliant" (from Av. *bāma- "light," bāmya- "light, luminous, bright," vīspô.bāma- "all resplendent," from bā- "to shine;" cf. Skt. bhāti- "light, splendor") + dâd "given," from dâdan "to give" (O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer," facere "to do, to make;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do").

morning star
  روجا، ستاره‌ی ِ بامداد   
rujâ (#), setâre-ye bâmdâd (#)

Fr.: étoile du matin   

Not actually a star, but the planet Venus shining brightly in the east just before or at sunrise. Opposed to → evening star.

morning; → star.

Rujâ "morning star" in Tabari, "star" in Gilaki. This word is a variant of official Pers. ruz "day," since in Tabari and Gilaki the phoneme z is sometimes changed into j, as in rujin = rowzan "window" and jir or jer = zir "under." Therefore it is related to rowšan "bright, clear," rowzan "window, aperture;" foruq "light," afruxtan "to light, kindle;" Mid.Pers. rôšn "light; bright, luminous," rôc "day;" O.Pers. raucah-rocânak "window;" O.Pers. raocah- "light, luminous; daylight;" Av. raocana- "bright, shining, radiant;" akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" L. lumen (gen. luminis) "light," from lucere "to shine," related to lux "light," lucidus "clear," luna, "moon;" Fr. lumière "light;" O.E. leoht, leht, from W.Gmc. *leukhtam (cf. O.Fris. liacht, M.Du. lucht, Ger. Licht), from PIE *leuk- "light, brightness;" → morning; → star.

morphism
  ریخت‌مندی   
rixtmandi

Fr.: morphisme   

A → mapping between two → objects in a → category.

morphology; → -ism.

From rixt, → morphology, + -mandi, → ism.

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