An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 712
Bahrâm (#)

Fr.: Mars   

Fourth planet from Sun and the seventh largest. Mass 6.42 × 1026 g (0.11 Earth's); radius 3397 km. Mean distance from Sun 1.52 A.U.. Sidereal period 687 days; synodic period 779.9 days. Surface temperature 248 K., rotational period 24h37m22s.6. Obliquity 23°59'. Atmosphere more than 90% CO2, traces of O2, CO, H2O. Two tiny satellites (Phobos and Deimos), both of which are locked in synchronous rotation with Mars.

Late M.E., from L. Mars the Roman god of war, Ares in Gk. mythology.

Bahrâm, from Mid.Pers. Vahrâm, from Vahrân "god of victory," from Av. vərəθraγna- "victory, breaking the defence, the god of victory." The first element vərəθra- "shield, defensive power," cf. Skt. vrtrá- "defence, name of a demon slain by Indra," Arm. vahagan name of a god (loanword from Iranian). The second element γna-, from Av., also O.Pers., jan-, gan- "to strike, hit, smite, kill" (jantar- "smiter"); cf. Mod.Pers. zadan, zan- "to strike, beat;" Mid.Pers. zatan, žatan; Skt. han- "to strike, beat" (hantar- "smiter, killer"); Gk. theinein "to strike," phonos "murder;" L. fendere "to strike, push;" Gmc. *gundjo "war, battle;" PIE *gwhen- "to strike, kill."

Mars datum
  فرازبن ِ بهرام   
farâzbon-e Bahrâm


The → zero point of elevation on Mars. It is the elevation at which the atmosphere pressure is 6.1 millibars, or 610 → Pascals. Atmosphere pressure has to be used because Mars has no ocean, and "sea level" cannot be used like on Earth. More formally, the datum is a fourth-order, fourth-degree surface of equal → gravitational potential (determined from the Viking orbiter spacecraft) such that the pressure of the atmosphere is 6.1 millibars (source: Lunar and Planetary Institute, USRA).

Mars; → datum.

Mars Trojan
  ترویایی ِ بهرام   
troyâ-yi-ye Bahrâm

Fr.: trojan de Mars   

A member of the family of → asteroids located at either of the stable → Lagrangian points (L4 or L5) of the orbit of → Mars.

Mars; → Trojan asteroid.


Fr.: tremblement de Mars   

A quake on the → planet Mars, probably caused by some phenomena other than → tectonic plate motions. Unlike Earth, Mars seems to lack tectonic plates. Therefore, its quakes are thought to arise from the slow cooling of the planet over time, which causes the → crust to contract and develop fractures. These quakes can also come from the impact of → meteorites and possibly the movement of → magma deep below the surface. On April 6, 2019, the instrument called Seismic Experiment for Interior Structure (SEIS) on NASA's Mars → InSight Mission lander recorded quakes that appear to have come from inside the planet, the first time ever a likely marsquake.

Mars; → quake.

  بهرامی، مریخی   
Bahrâmi (#), Merixi (#)

Fr.: martien   

Of, relating to, or like the planet → Mars.

M.E. marcien, from L. Marti(us) of, belonging to → Mars + -an a suffix of adjectives.

Martian meteorite
  شخانه‌ی ِ بهرامی، شهاب‌سنگ ِ ~   
šaxâne-ye Bahrâmi, šahâbsang-e ~

Fr.: météorite martienne   

A piece of rock that was ejected from the Martian surface into space by the impact of an asteroid or comet, and landed on Earth. So far about 100 Martian meteorites have been collected. These meteorites have elemental and isotopic compositions that match those of the Martian crust as measured by NASA's Mars exploration missions.

Martian; → meteorite.

Martian plume
  پرک ِ بهرام   
parrak-e Bahrâm

Fr.: plume de Mars   

A slender, cloudy projection sometimes seen to extend from the surface of → Mars to very high altitudes. Noted and confirmed by amateur astronomers on photos of Mars in March 2012, possibly similar plumes have been found on archived images as far back as 1997. The plumes reach 200 km up, which seems too high for them to be related to wind-blown surface dust. Since one plume lasted for more than 10 days, it seemed too long lasting to be related to → aurora. The origin of this phenomenon is not yet known.

Martian; → plume.


Fr.: mascon   

A region on the surface of the → Moon where the → gravitational attraction is slightly higher than normal due to the presence of dense rock.

Short for mass concentration; → mass; → concentration.

narin (#)

Fr.: masculin   

1) Having qualities appropriate to or usually associated with a man.
2) Of, relating to, or constituting the gender that ordinarily includes most words or grammatical forms referring to males (

M.E. masculin, from O.Fr. masculin "of the male sex," from L. masculinus "male, of masculine gender," from masculus "male, masculine; worthy of a man," diminutive of mas "male person, male," of unknown origin.

Narin, from nar, → male.

meyzer (#)

Fr.: maser   

1) A source of very intense, narrow-band, coherent microwave radiation involving → stimulated emission, as in the → laser.
2) A device that generates such radiation.
3) In astronomy, maser emission detected from a number of molecules and associated with several environments: the vicinity of newly forming stars and → H II regions (OH, water, SiO, and methanol masers); the circumstellar shells of evolved stars, i.e. red giants and supergiants (OH, water, and SiO masers); the shocked regions where supernova remnants are expanding into an adjacent molecular cloud (OH masers); and the nuclei and jets of active galaxies (OH and water masers). The hydroxyl radical (OH) was the first interstellar maser detected (Weinreb et al. 1963).

Maser stands for Microwave Amplification by Stimulated Emission of Radiation; → laser.

maser emission
  گسیل ِ میزری   
gosil-e meyzeri (#)

Fr.: émission maser   

An emission arising from the → maser process.

maser; → emission.

  ۱) ماسک؛ ۲) ماسک زدن   
1) mâsk (#); 2) mâsk zadan (#)

Fr.: 1) masque; 2) masquer   

1) Something that serves to cover or conceal.
Electronics: A pattern used to control the configuration of conducting material deposited or etched onto a semiconductor chip.
2) Electronics: To override one signal with a stronger one.

From M.Fr. masque "covering to hide or guard the face," from It. maschera, from M.L. masca "mask, specter, nightmare," of uncertain origin.

1) Mâsk, loan from Fr., as above; 2) with verb zadan "to make, to do," originally "to strike, beat; to do; to play an instrument" (Mid.Pers. zatan, žatan; O.Pers./Av. jan-, gan- "to strike, hit, smite, kill" (jantar- "smiter"); cf. Skt. han- "to strike, beat" (hantar- "smiter, killer"); Gk. theinein "to strike;" L. fendere "to strike, push;" Gmc. *gundjo "war, battle;" PIE *gwhen- "to strike, kill").


Fr.: masque, masquage   

1) A method of improving → spatial resolution of images. → pupil masking; → unsharp masking.
2) Computers: The process of specifying a number of values that allow extracting desired information from a set of characters or bits while suppressing the undesired information.

Verbal noun of → mask.

  ۱) جرم، غند؛ ۲) توده، انبوه   
1) jerm (#), qond (#); 2) tudé (#), anbuh (#)

Fr.: masse   

1) A measure of the amount of material in an object, defined either by the inertial properties of the object or by its gravitational influence on other bodies. See also → inertial mass, → gravitational mass.
2) A considerable assemblage, number, or quantity.

From O.Fr. masse "lump," from L. massa "kneaded dough, lump," from Gk. maza "barley cake, lump, mass, ball," related to massein "to knead."

Jerm, from Ar. jirm.
Qond "assembled, collected; a crowd," related to gondé "coarse, thick; big;" Mid.Pers. gund "troop, group, gathering;" loaned into Arm. gund and Ar. jund.
Tudé "heap, stack, tumulus;" cf. Kurd. tavda "all, total;" Tati tâya "heap, mass;" Sogd. tuδē "heap, mass." Perhaps related to PIE *teuta- "people, tribe;" cf. Lith. tauta, Oscan touto, O.Irish tuath, Goth. þiuda, O.E. þeod "people, folk, race."
Anbuh "numerous, abundant," from Proto-Iranian *ham-buH- "to come together," from ham- "together," → com- + *buH- "to be , become," Av. ham.bauu- "to come together, unite," from ham- as above + bauu-, bu- "to be, become," O.Pers. bav- "to be, become," Mod.Pers. budan "to be," Skt. bhavati "becomes, happens," PIE base *bheu-, *bhu- "to grow, become;" cf. Gk. phu- "become," P.Gmc. *beo-, *beu-, E. be.

mass absorption coefficient
  همگر ِ درشم ِ جرمی   
hamgar-e daršm-e jermi

Fr.: coefficient d'absorption de masse   

A measure of the rate of absorption of radiation, expressed as the linear absorption coefficient divided by the density of the medium through which radiation is passing.

mass; → absorption; → coefficient.

mass defect
  کاست ِ جرم   
kâst-e jerm

Fr.: défaut de masse   

The difference between the rest mass of an atomic nucleus (made up of protons and neutrons) and the sum of the masses of its individual protons and neutrons. The mass difference is equal to the released binding energy. Also called mass deficiency

mass; → defect.

mass density
  چگالی ِ جرمی   
cagâli-ye jermi

Fr.: densité massique   

The mass per unit area of the ring material, integrated through the thickness of the ring. Sometimes called → surface density (Ellis et al., 2007, Planetary Ring Systems, Springer).

mass; → density.

mass discrepancy
  ناهم‌خوانی ِ جرم   
nâhamxâni-ye jerm

Fr.: écart de masse   

1) For → massive stars and → supergiants, the difference between the → spectroscopic mass and the → evolutionary mass. Early studies found that the spectroscopic mass was systematically less than the evolutionary mass by as much as a factor of 2 for supergiants. Improvements in the stellar atmosphere models (taking into account → line blanketing) have decreased or eliminated the size of the discrepancy for Galactic stars. There is still a mass discrepancy for the hottest → O stars in the → Magellanic Clouds (See, e.g. Massey et al. 2009, ApJ 692, 618).
2) For a → cluster of galaxies, the apparent difference between the mass of the cluster obtained by using the → virial theorem, and the mass inferred from the total luminosities of the member galaxies.

mass; → discrepancy.

mass energy
  کاروژ ِ جرم   
kâruž-e jerm

Fr.: énergie de masse   

The energy (E) associated with a mass (m), as specified by the → mass-energy equivalence  E = mc2, where c is the → speed of light. For a moving body the total energy of the particle is expressed by: E2 = m2c4 + p2c2, where m is → rest mass and p → momentum.

mass; → energy.

mass extinction
  خاموشی ِ انبوه   
xâmuši-ye anbuh

Fr.: extinction en masse   

An event in the history of life on Earth in which large numbers of species (sometimes more than 90% of some species) vanish in a relatively short period of time. In spite of controversy, it is generally recognized that there have been at least six major mass extinctions. These occurred in the late Cambrian (500 million years ago), in the late Ordovician (440 million years ago), in the late Devonian (365 million years ago), at the end of the Permian (245 million years ago), in the late Triassic (208 million years ago), and at the end of the Cretaceous (65 million years ago).

mass; → extinction.

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