An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < -sc Sag sam sat sca sca Sch sci Sea sec sec see sel sem sen ser Sey Sha she sho sid sig SIM sim Sin ske sle Smi SNR sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi Spo squ sta sta sta sta Ste ste ste sto str str str sub sub sub sun sup sup sup sup sur sus sym syn syz > >>

Number of Results: 1381
SNR shell
  پوسته‌ی ِ بازمانده‌ی ِ اَبَر-نوختر   
pustey-e bâzmânde-ye abar-now-axtar

Fr.: coquille de reste de supernova   

A ring-like structure of swept-up → gas and → dust around a → supernova remnant. See also: → free expansion phase, → Sedov-Taylor phase, → snowplow phase.

supernova remnant (SNR); → shell.

Sobolev approximation
  نزدینش ِ سوبولف   
nazdineš-e Sobolev

Fr.: approximation de Sobolev   

A method allowing for a simplified solution to the → radiative transfer equation at frequencies of spectral lines in media moving with a high velocity gradient. This method assumes that the macroscopic velocity gradients are more important than local random variations of thermal line width: dv/dr > vth/l, where dv/dr is the velocity gradient, vth is the thermal broadening of the line, and l the length scale. The Sobolev approximation is only valid if the conditions of the gas do not change over the → Sobolev length. Under the Sobolev approximation, each point in the medium is isolated from other points, and the → radiative transfer problem becomes a local one and therefore much easier to solve.

Named after the Russian astronomer Viktor Viktorovich Sobolev, Moving Envelopes of Stars [in Russian], Leningr. Gos. Univ., Leningrad (1947) [translated by S. Gaposchkin, Harvard Univ. Press, Cambridge, Mass. (1960)]; → approximation.

Sobolev length
  درازای ِ سوبولف   
derâzâ-ye Sobolev

Fr.: longueur de Sobolev   

In the → Sobolev approximation, the length over which the conditions of the gas do not change and the approximation is valid. It is expressed by: ls = vth/(dv/dr), where vth is the thermal line width and (dv/dr) the velocity gradient. In other words, the length over which the profile function of a line is shifted through a distance equal to its own width by the macroscopic velocity gradients that exist in the moving medium.

Sobolev approximation; → length.


Fr.: social   

Of or pertaining to human society.

society; → -al.


Fr.: socialisation   

A continuing process whereby an individual acquires a personal identity and learns the norms, values, behavior, and social skills appropriate to his or her social position (

socialize; → -tion.


Fr.: socialiser   

To make social; make fit for life in companionship with others (

social; → -ize.


Fr.: sociétal   

Of or pertaining to social groups, their activities, or to social relations.

From societ-, from → society, + → -al.

Hazâni, from hazân-, from hazâné, → society, + -i, → -al.


Fr.: société   

An organized group of persons associated together for scientific, cultural, or other purposes; e.g. a physical society. See also:
associate, → association, → dissociate, → dissociation, → social, → socialization, → socialize, → societal.

M.E., from O.Fr. societe, from L. societatem (nominative societas), from socius "companion," → associate.

Hazâné, from Av. hacenay- "getting together, association," from verb hac-, hax- "to associate, follow, accompany" (haxay-, hašy-, haš- "friend"), hacaiti "follows;" hacā "from, out of;" O.Pers. hacā "from" (Mid.Pers. hac "from;" Mod.Pers. az "from"); PIE base *sekw- "to follow;" cf. Skt. sac- "to be associated or united with," sácate "accompanies, follows," sácā "with;" Gk. hepesthai "to follow;" L. sequi "to follow."


Fr.: sociologie   

The science or study of the origin, development, organization, and functioning of human society; the science of the fundamental laws of social relations, institutions, etc. (

society; → -logy.

  سقراطی، سقراتی   

Fr.: socratique   

Of or pertaining to Socrates or his philosophy, followers, etc., → Socratic irony, → Socratic method.

Socrates (469?-399 B.C.), Athenian philosopher.

Socratic irony
  گواژه‌ی ِ سقراطی، ~ سقراتی   
govâže-ye Soqrâti

Fr.: ironie socratique   

A means by which the pretended ignorance of a skillful questioner leads the person answering to expose his own ignorance (Collins).

Socratic; → irony.

Socratic method
  روش ِ سقراطی، ~ سقراتی   
raveš-e Soqrâti

Fr.: méthode socratique   

The use of questions, as employed by Socrates, to develop a latent idea, as in the mind of a pupil, or to elicit admissions, as from an opponent, tending to establish a proposition (

Socratic; → method.

sodiom (#)

Fr.: sodium   

A metallic chemical element; symbol Na (L. natrium]. Atomic number 11; atomic weight 22.98977; melting point 97.81°C; boiling point 892.9°C; specific gravity 0.971 at 20°C. It was discovered in 1807 by the English chemist Humphry Davy from electrolysis of caustic soda (NaOH).

Sodium, from soda (NaOH).

Sodium Moon Spot (SMS)
  لکه‌ی ِ سودیومی ِ مانگ   
lake-ye sodiomi-ye Mâng

Fr.: tache de sodium de la Lune   

The → sodium tail of the Moon as it appears in the sky opposite the Sun. The SMS undergoes changes in shape and brightness. It is brighter when the → new moon occurs at → perigee, when the new moon is north of the → ecliptic, and approximately five hours after the new moon.

sodium; → Moon; → spot.

sodium tail
  دم ِ سودیومی   
dom-e sodiomi

Fr.: queue de sodium   

1) A kind of → cometary tail appearing in some → comets, such as → Hale-Bopp. Sodium tails arise from the very strong → fluorescence of their sodium atom → D lines in the visible. They are rapidly accelerated to high velocities by the Sun, forming a very straight tail distinct from the → ion tail. The release mechanism of sodium from comets is still a matter of debate. Also called → neutral tail.
2) → sodium tail of the Moon.
3) A comet-like tail of Mercury similar to that of the Moon, but much longer, stretching up to 3.5 million km.

sodium; → tail.

sodium tail of the Moon
  دنباله‌ی ِ سودیومی ِ مانگ   
donbâle-ye sodiomi-ye Mâng

Fr.: queue de sodium de la Lune   

A comet-like tail of the Moon comprised of → sodium (Na) atoms and invisible to the naked eye. The lunar surface is constantly bombarded by the → solar wind, → photons, and → meteoroids, which can liberate Na atoms from the → regolith. These atoms are subsequently accelerated by solar → radiation pressure to form a long comet-like tail opposite the Sun. Near → new moon, this diffuse cloud of Na atoms encounters the Earth's gravity and is "pinched" into a beam of enhanced density. This beam appears as the ~3° diameter Sodium Moon Spot (SMS) seen in the sky opposite the Sun. The spot is about five times the diameter of the → full moon, and is 50 times fainter than can be seen with the unaided eye. The spot is reflected light from millions of Na atoms that two days earlier were on the surface of the Moon. This spot is visible to sensitive cameras equipped with filters tuned to the orange light emitted by Na atoms near 589.3 nm (Baumgardner et al., 2021 Journal of Geophysical Research: Planets DOI: 10.1029/2020je006671).

sodium; → tail; → Moon.

narm (#)

Fr.: mou   

General: Delicate in texture, grain, or fiber.
Not bright or glaring.
Physics: Of a beam of particles or electromagnetic radiation, having relatively low energy, as opposed to → hard. → soft X-rays

M.E. softe "yielding, gentle, mild;" O.E. softe "gentle, easy;" cf. O.S. safti, O.H.G. semfti, Ger. sanft, M.Du. sachte, Du. zacht.

Narm "soft; smooth; mild," from Mid.Pers. narm "soft; humble."

soft binary
  درین ِ نرم   
dorin-e narm

Fr.: binaire mou   

In → stellar dynamics studies of → three-body encounters, a → binary system whose → binding energy is smaller than the typical → kinetic energy of the relative motion of an incoming third body. See also → hard binary.

soft; → binary.

soft gamma repeater (SGR)
  بازگرشگر ِ گامای ِ نرم   
bâzgaršgar-e gâmmâ-ye narm

Fr.: répéteur gamma mou   

A member of a small class of objects which emit intense bursts of → gamma rays and → X-rays (> 100 keV) at irregular intervals. The bursts last for some 100 milli-seconds. It is conjectured that they are → magnetars. See also → starquake.

soft; → gamma rays; → repeater.

soft gamma-ray repeater (SGR)
  بازگرشگر ِ پرتوهای ِ گامای ِ نرم   
bâzgaršgar-e partowhâ-ye gâmmâ-ye narm

Fr.: répéteur des rayons gamma mous   

Same as → soft gamma repeater (SGR).

soft; → gamma ray; → repeater.

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