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: 458
luminous infrared galaxy (LIRG)
  کهکشان ِ فروسرخ ِ تابان   
kahkešân-e forusorx-e tâbân

Fr.: galaxie lumineuse en infrarouge   

A galaxy that emits most of its energy in the infrared and whose infrared luminosity (in the 8-1000 µm range) is more than 1011 solar luminosities. → ultraluminous infrared galaxy.

luminous; → infrared; → galaxy.

luminous intensity
  درتنویی ِ تابشی   
dartanuyi-ye tâbeši

Fr.: intensité lumineuse   

A measure of the amount of light that a point source radiates in a given direction. It is expressed by the luminous flux per unit leaving the source in the direction per unit of solid angle.

luminous; → intensity.

luminous matter
  مادّه‌ی ِ تابان   
mâdde-ye tâbân (#)

Fr.: matière lumineuse   

Ordinary baryonic matter that can emit electromagnetic radiation, as opposed to → dark matter.

luminous; → matter.

luminous red nova (LRN)
  نو‌اختر ِ سرخ ِ تابان   
now-axtar-e sorx-e tâbân

Fr.: nova rouge lumineuse   

A stellar explosion thought to be caused by the → merger of stars in a → binary system. They are characterized by a distinct red color, and a → light curve that lingers with resurgent brightness in the → infrared. The luminosity of the explosion is between that of a → supernova and a → nova.

luminous; → red; → nova

lunar
  مانگی، ماهی   
mângi (#), mahi (#)

Fr.: lunaire   

Of or pertaining to the moon.

From O.Fr. lunaire, from L. lunaris "of the moon," from luna "moon" (with capital L) "moon goddess," from *leuksna- (cf. O.C.S. luna "moon," O.Pruss. lauxnos "stars," M.Ir. luan "light, moon"), from the same source as lux, lumen "light;" cognate with Pers. ruz, → day, rowšan "bright, clear."

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 precison, this dictionary uses mângi for "lunar."

lunar calendar
  گاهشمار ِ مانگی   
gâhšomâr-e mângi

Fr.: calendrier lunaire   

A calendar that is based on the cycles of the → lunar phase and involves the → lunar month and → lunar year. For example → Islamic calendar, → Vietnamese lunar calendar.

lunar; → calendar.

lunar crater
  لاوک ِ ماه، ~ ِ مانگی، کندال ِ ~   
lâvak-e mâh, ~ mângi, kandâl-e ~

Fr.: cratère lunaire   

A → crater on the surface of the Moon.

lunar; → crater.

lunar day
  روز ِ مانگ، ~ ِ مانگی   
ruz-e mâng, ~ mângi

Fr.: jour lunaire   

The interval between two successive sunrises for an observer standing on the Moon. This is not the rotational period of the Moon, because the Moon-Earth system has moved round the Sun during that period. It is equal to the length of a → synodic month (29.5306 days).

lunar; → day.

lunar dust
  غبار ِ ماه   
qobâr-e mâh

Fr.: poussière lunaire   

A fine, powder-like dust covering the Moon's surface. → regolith. It is formed when meteoroids crash on the Moon's surface, heating and pulverizing rocks, which contain silica and metals. Since there is no wind or water to smooth rough edges, the tiny grains are sharp and jagged, and cling to nearly everything. Their main chemical compositions are SiO2 (about 45%) and Al2O3 (about 15%). The dust grains have an average size of 19 microns (40% smaller than hair).

lunar; → dust.

lunar eclipse
  ماه‌گرفت   
mâhgereft (#)

Fr.: éclipse de lune   

The → darkening of the → Moon which occurs when the Moon enters the → umbra of the → Earth's shadow. This phenomenon can occur only when the → full Moon is near one of the → lunar nodes of its → orbit around the Earth. There will be a → total eclipse if the entire Moon enters the umbra, otherwise the eclipse will be partial when the Moon is somewhat to the north or south of the node and does not cross the shadow entirely. During the eclipse the Moon looks more or less dark, depending especially on the transparency of the Earth's → atmosphere. The → refraction of Sun's light through the atmosphere sometimes gives a red color to the eclipsed Moon. Colored fringes can be seen around the shadow edge during → partial eclipses. Because an eclipse of the Moon is due to the cutting off of the Sun's light, it is visible from the entire hemisphere where the Moon is above the horizon. The maximum duration of a total lunar eclipse, when the Moon passes through the shadow centrally, is 1h 47m (M.S.: SDE).

lunar; → eclipse.

lunar ecliptic limit
  حد ِ هورپهی ِ ماه   
hadd-e hurpehi-ye mâh

Fr.: limite écliptique de la Lune   

The farthest distance from a → lunar orbit node within which, if the Moon happens to be at full, a lunar eclipse may occur. The lunar ecliptic limit extends about 12° on each side of the node.

lunar; → ecliptic; → limit.

lunar exosphere
  برون‌سپهر ِ ماه   
borun-sepehr-e mâh

Fr.: exosphère lunaire   

An extremely thin gathering of gas surrounding the → Moon. It is made up of → atoms and → ions generated at the Moon's surface by interaction with → solar radiation, → plasma in the Earth's → magnetosphere, or → micrometeorites.

lunar; → exosphere.

lunar geology
  زمین‌شناسی ِ ماه   
zaminšenâsi-ye mâh

Fr.: géologie lunaire   

The study of the → Moon's → crust, → rocks, strata (→ stratum), etc.

lunar; → geology.

lunar highland
  کوهسار ِ مانگی   
kuhsâr-e mângi

Fr.: hauts plateaux lunaires   

A light color area on the → Moon, as contrasted with → lunar maria. Also called terra.

lunar; → highland.

lunar horizon glow
  فروغ ِ افق ِ ماه   
foruq-e ofoq-e mâh

Fr.: éclat de l'horizon lunaire   

A very bright crescent of light glowing on the lunar horizon at → sunset or just before → sunrise. It has been suggested that → lunar dust is transported electrically high into sky, allowing sunlight to scatter and create glows. On the day side of the → Moon, solar → ultraviolet radiation is strong enough to kick → electrons from → dust grains in the lunar soil. Removal of electrons, which have a negative electric charge, leaves the dust with a positive electric charge. Since like charges repel, the positively charged dust particles get pushed away from each other, and the only direction not blocked by more dust is up. In the 1960s, Surveyor probes filmed a glowing cloud floating just above the lunar surface during sunrise. Later, Apollo 17 astronaut Gene Cernan, while orbiting the Moon, recorded a similar phenomenon at the sharp line where lunar day meets night, called the → terminator.

lunar; → horizon; → glow.

lunar mansion
  منزل ِ ماه   
manzel-e mâh (#)

Fr.: maison lunaire   

One of the 28 divisions of the sky, identified by the prominent stars in them, that the Moon passes through during its monthly cycle, as used in ancient Chinese, Hindu, and Arab astronomy/astrology.

From O.Fr. mansion, from L. mansionem (nom. mansio) "a staying, a remaining, night quarters, station," from manere "to stay, abide" (Fr. maison, ménage; E. manor, mansion, permanent); cf. Pers. mân "house, home," mândan "to remain, stay, relinquish, leave;" Mid.Pers. mândan "to remain, stay;" O.Pers. mān- "to remain, dwell;" Av. man- "to remain, dwell; to wait;" Gk. menein "to remain;" PIE base *men- "to remain, wait for."

Manzel, from Ar. "dwelling, habitation, mansion."

lunar mare
   \"دریای ِ ماه\"   
"daryâ-ye mâh" (#)

Fr.: mer lunaire   

An area on the surface of the → Moon that appears darker and smoother than its surroundings. Once thought to be seas, lunar maria are now known to be basaltic basins created by volcanic → lava floods; plural maria.

lunar; L. mare "sea," plural form maria, because Galileo thought the dark featureless areas on the Moon were → seas.

lunar maria
   \"دریاهای ِ ماه\"   
"daryâhâ-ye mâh" (#)

Fr.: mer lunaire   

Plural of → lunar mare.

lunar mare.

lunar mass
  جرم ِ ماه، ~ مانگ   
jerm-e mâh (#), ~ mâng

Fr.: masse lunaire, masse de la Lune   

The mass of the → Moon, which is 7.35 x 1022 kg, about 1/81 of the Earth's mass.

lunar; → mass.

lunar month
  ماه ِ مانگی   
mâh-e mângi

Fr.: mois lunaire   

The average time between successive new or full moons. Also called → synodic month, → lunation.

lunar; → month.

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