An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -me mac mag mag mag mag mai man Mar mas mas matmea mec mem mer Mes Met met mic mic mil min Mir mix mod mol mom moo mot mul mul mys > >>

Number of Results: 663
Möbius band
  باند ِ موی‌بیوس   
bând-e Möbius

Fr.: ruban de Möbius   

A surface with only one side, made by putting a simple twist in a long, rectangular strip of paper, then pasting the ends together.

After the German astronomer and geometer August Ferdinand Möbius (1790-1868); → band.

Mössbauer effect
  ا ُسکر ِ موسباؤر   
oskar-e Mössbauer

Fr.: effet Mössbauer   

The resonant and recoil-free emission and absorption of gamma rays by atoms bound in a solid form.

Named after Rudolf Mößbauer (1929-), a German physicist who studied gamma rays from nuclear transitions, and discovered this phenomenon in 1957; → effect.

  ۱) میانگین؛ ۲) چماردن   
1) miyângin (#); 2) cemârdan

Fr.: 1) moyenne; 2) signifier, vouloir dire   

1a) General: A quantity having a value intermediate between the values of other quantities; an average.
1b) → arithmetic mean.
1c) → geometric mean.
1d) → harmonic mean.
1e) → weighted mean.
1f) → root mean square.
2) To have as its sense or signification; signify.

1) From O.Fr. meien, from L. medianus "of or that is in the middle," → median.
2) Verb of → meaning.

1) Miyângin "the middle; middle-sized; the middle pearl in a string," from miyân, → middle, + -gin a suffix forming adjectives of possession.
2) → meaning.

mean anomaly
  ناسانی ِ میانگین   
nâsâni-ye miyângin

Fr.: anomalie moyenne   

The angle between the periapsis of an orbit and the position of a hypothetical body that orbits in the same period as the real one but at a constant mean angular velocity.

mean; → anomaly.

mean catalog place
  جای ِ میانگین ِ کاتالوگی   
jâ-ye miyângin-e kâtâlogi

Fr.: position catalogue moyenne   

That point on the → celestial sphere at which an object would be seen from the solar system → barycenter affected by the → e-terms → aberration.

catalog; → mean; → place.

mean daily motion
  جنبش ِ روزانه‌ی ِ میانگین   
jenbeš-e ruzâne-ye miyângin (#)

Fr.: mouvement diurne moyen   

The average movement of a body along its orbit in one day, usually expressed in degrees.

mean; → diurnal; → motion.

mean element
  بن‌پار ِ میانگین   
bonpâr-e miyângin

Fr.: élément moyen   

An element of an adopted reference orbit that approximates the actual, perturbed orbit. Mean elements may serve as the basis for calculating perturbations.

mean; → element.

mean equator
  هموگار ِ میانگین   
hamugâr-e miyângin

Fr.: équateur moyen   

The orientation the Earth's equator would have if the nutation was subtracted.

mean; → equator.

mean equinox
  هموگان ِ میانگین   
hamugân-e miyângin

Fr.: équinoxe moyen   

A fictitious equinox whose position is that of the vernal equinox at a particular epoch with the effect of nutation removed.

mean; → equinox.

mean free path
  پویش ِ آزاد ِ میانگین   
puyeš-e âzâd-e miyângin (#)

Fr.: libre parcours moyen   

The mean distance which a particle moves between two successive collisions with other particles of the medium. Mean free path is inversely proportional to the number of particles per cm3 (n), and the collision → cross section (σ). In the case of a gas with molecules having a diameter of d, the cross section is equal to the area of a circle of radius d, i.e. σ = πd2, and the mean free path is given by: l = 1/(nσ). Taking into account the relative velocity distribution of the colliding molecules, l = 1/(√2 . nσ). For a gas at one atmosphere pressure and room temperature, the average distance between molecules is roughly 3.5 × 10-7 cm, that is some 35 times the diameter of a molecule. Taking the gas density n = 2.4 × 1014 molecules cm-3, and a typical diameter d = 2 × 10-8 cm for a molecule, the mean free path is 3.3 × 10-5 cm. This means that the average distance between collisions is about 95 times the average distance between molecules.

mean; → free; → path.

Puyeš, verbal noun of puyidan "to run, trot; wander," from Mid.Pers. pôy-, pwd- "to run;" cf. Gk. speudein "to hasten;" Lith. spudinti; âzâd, → free; miyângin, → mean.

mean life
  زیست ِ میانگین   
zist-e miyângin

Fr.: vie moyenne   

The average amount of time an unstable radioisotope exists before it decays, It is equal to 1.44 times the half-life.

mean; → life.

mean molecular weight
  وزن ِ مولکولی ِ میانگین   
vazn-e molekuli-ye miyângin (#)

Fr.: poids moléculaire moyen   

The total atomic or molecular weight divided by the total number of particles. For instance, the mean molecular weight of a plasma of pure ionized 4He would be 4 (the atomic mass number) divided by 3, the total number of particles (1 nucleus plus 2 electrons), i.e. 4/3.

mean; → molecular; → weight.

mean moon
  ماه ِ میانگین   
mâh-e miyângin (#)

Fr.: lune moyenne   

A fictitious Moon that has the same average motion as the true Moon but that is not subject to any gravitational perturbations by other bodies.

mean; → moon.

mean motion
  جنبش ِ میانگین   
jonbeš-e miyângin (#)

Fr.: mouvement moyen   

The average angular velocity of a satellite in an elliptical orbit.

mean; → motion.

mean parallax
  دیدگشت ِ میانگین   
didgašt-e miyângin

Fr.: parallaxe moyenne   

The parallax, derived by means of statistical studies of brightness and motions, for a large group of stars whose individual parallaxes cannot be measured.

mean; → parallax.

mean place
  جای ِ میانگین   
jâ-ye miyângin

Fr.: position moyenne   

An object's celestial position as determined for a given mean equator and equinox. → mean position.

mean; → place.

mean pole
  قطب ِ میانگین   
qotb-e miyângin

Fr.: pôle moyen   

The direction of the Earth's axis at a particular epoch if the nutation is ignored.

mean; → pole.

mean position
  نهش ِ میانگین   
neheš-e miyângin

Fr.: position moyenne   

Same as → mean place.

mean; → position.

mean profile
  فراپال ِ میانگین   
farâpâl-e miyângin

Fr.: profil moyen   

The shape of a pulsar's pulse as determined by averaging several pulses.

mean; → profile.

mean sidereal day
  روز ِ اختری ِ میانگین   
ruz-e axtari-ye miyângin

Fr.: jour sidéral moyen   

The average time interval between two successive → upper transits of the → mean equinox.

mean; → sidereal; → day.

<< < -me mac mag mag mag mag mai man Mar mas mas matmea mec mem mer Mes Met met mic mic mil min Mir mix mod mol mom moo mot mul mul mys > >>