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: 1295
spherical polar coordinate
  هماراهای ِ کره‌ای ِ قطبی   
hamârâhâ-ye kore-yi-ye qotbi

Fr.: coordonnées sphériques polaires   

Same as → spherical coordinates.

spherical; → polar; → coordinate

spherical symmetry
  همامونی ِ کُره‌ای   
hamâmuni-ye kore-yi

Fr.: symétrie sphérique   

A configuration in which the constituting parts are arranged concentrically around the center of a sphere.

spherical; → symmetry.

spherical triangle
  سه‌بر ِ کُره‌ای   
sebar-e kore-yi

Fr.: triangle sphérique   

A triangle drawn on the → surface of a → sphere. A spherical triangle, like a plane triangle, may be right, obtuse, acute, equilateral, isosceles, or scalene. The sum of the angles of a spherical triangle is greater than 180° (π) and less than 540° (3π). See also → spherical excess.

spherical; → triangle.

spheroid
  کُره‌وار   
korevâr

Fr.: sphéroïde   

A body that is shaped like a sphere but is not perfectly round, especially an ellipsoid that is generated by revolving an ellipse around one of its axes.

sphere; → -oid.

spheroidal
  کره‌وار   
korevâr (#)

Fr.: sphéroïdal   

Shaped like a → spheroid.

spheroid; → -al.

spherule
  گویل   
guyel

Fr.: sphérule   

Any of many vitrified droplets of rock formed by the solidification of molten meteoritic material that flows off a meteorite during its passage through the Earth's atmosphere. Sizes range typically from 10 to 200 microns.

"Small sphere," from → sphere + diminutive suffix → -ule.

Guyel "small globe," from guy "ball, sphere" (variants golulé, gullé, goruk, gulu, gudé; cf. Skt. guda- "ball, mouthful, lump, tumour," Pali gula- "ball," Gk. gloutos "rump," L. glomus "ball," globus "globe," Ger. Kugel, E. clot; PIE *gel- "to make into a ball") + -el diminutive suffix, → -ule.

Spica (α Virginis)
  سنبله   
Sonbolé (#)

Fr.: Spica   

The brightest star in the constellation → Virgo, and the 15th brightest star in the night sky. Also known as HD 116658. It is 260 → light-years distant from Earth. A → blue giant, it is a variable → eclipsing binary, with a period of 4.014 days. Both components are → B-type stars, the → primary being a → Beta Cephei variable near to core hydrogen exhaustion (→ spectral type B1 III-IV) and the → secondary a → main sequence star (B2 V). See, e.g., R.S. Schnerr et al., 2010, arXiv:1008.4260.

From L. spica "ear of grain," related to spina "thorn," corresponding to Gk. stakhys "grapes."

Sonbolé, from sonbol "an ear of corn; a hyacinth," from Ar. sumbul.

spicule
  سیخک   
sixak

Fr.: spicule   

Any of numerous vertical → spikes of → gas visible in the → monochromatic light of certain strong → spectral lines beyond the → Sun's limb. Spicules are short-lived phenomena, corresponding to rising → jets of gas that move upward at about 30km/sec up to 10,000 km and last only about 10 minutes.

From L. spiculum "spearhead, arrowhead, bee stinger," from spica "ear of grain" + -ulum, → -ule.

Sixak, from six "spur, spit; thorn; any pointed thing."

spider vane
  پره‌ی ِ تارتن   
parre-ye târtan

Fr.: araignée   

One of, usually three or four, diagonal supports that hold the → secondary mirror in a → reflecting telescope. Also called support vane.

M.E. spithre, O.E. M.E. spithra, akin to spinnan "to spin;" cf. M.L.G., M.Du., M.H.G., Ger. spinne, Du. spin "spider;" → vane.

Parré, → vane; târtan "spider," literally "weaver," composite word of with two cognate elements, the first one târ "thread, warp, string," related to tur "net, fishing net, snare," tâl "thread" (Borujerdi dialect), tân "thread, warp of a web," from the second element tan-, tanidan "to spin, twist, weave;" Mid.Pers. tanitan; Av. tan- to stretch, extend;" cf. Skt. tan- to stretch, extend;" tanoti "stretches," tántra- "warp; essence, main point;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch;" Lith. tiñklas "net, fishing net, snare," Latv. tikls "net;" PIE base *ten- "to stretch."

spike
  سیخک   
sixak (#)

Fr.: pointe   

1) A long, pointed → metal  → bar.
2) Physics: A → transient variation in → voltage or → current in an → electric circuit.

M.E. spik(e) from O.N. spikr "nail;" akin to M.L.G. spiker "nail."

Sixak, from six "spur, spit; thorn; any pointed thing," + -ak a suffix of similarity and nuance.

spin
  اسپین   
espin

Fr.: spin   

1) Mechanics: The rotation of a body about an axis through the body. To cause to turn around rapidly, as on an axis. To revolve or rotate rapidly,
2) Quantum mechanics: See → spin quantum number; → spin angular momentum.

M.E. spinnen; O.E. spinnan "to draw out and twist fibers into thread" (cf. O.N., O.Fris. spinna, Dan. spinde, Du. spinnen, O.H.G. spinnan, Ger. spinnen); cognate with Pers. tan-, tanidan "to spin, twist, weave" (Mid.Pers. tanitan; Av. tan- to stretch, extend;" cf. Skt. tan- to stretch, extend;" tanoti "stretches," tántra- "warp; essence, main point;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch;" Lith. tiñklas "net, fishing net, snare," Latv. tikls "net;" PIE base *ten- "to stretch").

Espin, loan from E., as above.

spin angular momentum
  جنباک ِ زاویه‌ای ِ اسپین   
jonbâk-e zâviyeyi-ye espin

Fr.: moment angulaire de spin   

An intrinsic quantum mechanical characteristic of a particle that has no classical counterpart but may loosely be likened to the classical → angular momentum of a particle arising from rotation about its own axis. The magnitude of spin angular momentum is given by the expression S = ħ √ s(s + 1), where s is the → spin quantum number. As an example, the spin of an electron is s = 1/2; this means that its spin angular momentum is (ħ /2) √ 3 or 0.91 x 10-34 J.s. In addition, the projection of an angular momentum onto some defined axis is also quantized, with a z-component Sz = msħ. The only values of ms (magnetic quantum number) are ± 1/2. See also → Stern-Gerlach experiment.

spin; → angular; → momentum.

spin magnetic moment
  گشتاور ِ مغناتیسی ِ اسپین   
gaštâvar-e meqnâtisi-ye espin (#)

Fr.: moment magnétique de spin   

The magnetic moment associated with the → spin angular momentum of a charged particle. The direction of the magnetic moment is opposite to the direction of the angular momentum. The magnitude of the magnetic moment is given by: μ = -g(q / 2m)J, where q is the charge, m is the mass, and J the angular momentum. The parameter g is a characteristic of the state of the atom. It would be 1 for a pure orbital moment, or 2 for a spin moment, or some other number in between for a complicated system like an atom. The quantity in the parenthesis for the electron is the → Bohr magneton. The electron spin magnetic moment is important in the → spin-orbit interaction which splits atomic energy levels and gives rise to → fine structure in the spectra of atoms. It is also a factor in the interaction of atom with external fields, → Zeeman effect.

spin; → magnetic moment.

spin quantum number
  عدد ِ کو‌آنتومی ِ اسپین   
adad-e kuântomi-ye espin

Fr.: nombre quantique de spin   

An integer or half-integer on which the magnitude of a particle's → spin angular momentum depends. It is expressed in units of → Planck's constant divided by 2π. Called also spin, denoted s. The spin of a particle can only have a value that is zero or a multiple of 1/2. Particles with half-integer spins, 1/2, 3/2, 5/2, ..., are → fermions. Particles with integer spin (0, 1, 2, ...) are called → bosons.

spin; → quantum; → number.

spin temperature
  دمای ِ اسپین   
damâ-ye espin

Fr.: température de spin   

The → excitation temperature of the → hyperfine structure levels of the → neutral hydrogen21-centimeter line.

spin; → temperature.

spin-down
  کند-چرخی   
kond-carxi

Fr.: ralentissement   

A phenomenon in which the rotation period of a pulsar steadily decreases with the pulsar age. The cause of the spin-down is magnetic torque due to the strong fields threading out from the pulsar. The magnetic energy is being converted to high-energy particles and radiation from the nebula. Observed spin-down rates range from about 10-5 seconds/year for the youngest pulsars to about 10-12 seconds/year for recycled pulsars. The Crab pulsar is slowing down at a rate of about 10-5 seconds/year. Knowing the rotation period and the lengthening rate of a pulsar leads to its age.

spin; down, M.E.; O.E. ofdune "downward," from dune "from the hill."

Kond-carxi, from kond "slow; dull" + carxrotate + -i noun suffix.

spin-flip scattering
  پراکنش با وارونی ِ اسپین   
parâkaneš bâ vâruni-ye espin

Fr.: diffusion avec renversement du spin   

Quantum mechanics: The scattering of a particle that reverses the spin direction.

spin; flip, from flip-flap; → scattering.

Parâkaneš, → scattering; "with;" vâruni, noun from vârun, → inverse; espin, → spin.

spin-orbit coupling
  جفسری ِ اسپین-مدار، جفتش ِ ~   
jafsari-ye espin-madâr, jofteš-e ~

Fr.: couplage spin-orbite   

1) Astro.: A relationship between the orbital period of one body around another and its rotational period on its axis. The relationship results from tidal forces between the two bodies. For example, the rotation period of the Moon equals its revolution period around the Earth.
2) Quantum mechanics: The interaction between a particle's → spin angular momentum and its → orbital angular momentum.

spin; → orbit; → coupling.

spindle
  دوک   
duk (#)

Fr.: fuseau   

A rounded rod, usually of wood, tapering toward each end, used in hand-spinning to twist into thread the fibers drawn from the mass on the distaff, and on which the thread is wound as it is spun (Dictionary.com).

M.E. spindel, O.E. spin(e)l, from spinnan, → spin.

Duk "spindle," variants dêk, dik, ultimately from Proto-Ir. *dau- "to run;" cf. Pers. dow-, davidan "to run" (Cheung 2007).

spine
  خار   
xâr (#)

Fr.: épine   

1) In 3D → magnetic reconnection models of solar plasma, a field line crossing the → fan at the → magnetic null point. See also → fan (Lau & Finn. 1990, ApJ 350, 672; Parnell et al. 1996, Physics of Plasmas 3, 759).
2) A very narrow line of light extending back from the coma into the tail of some → comets.

M.E., from O.Fr. espine, from L. spina "backbone," originally "thorn, prickle," cf. L. spica "ear of corn," O.N. spikr "nail;" from PIE *spei- "sharp point."

Xâr "spine, thorn," related to xal-, xalidan "to prick, to pierce," xâridan "to scratch, itch;" Av. xvara- "wound, sore."

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