An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The empirical law that predicts the variation of → sunspot latitudes during a → solar cycle. At the start of a sunspot cycle, sunspots tend to appear around 30° to 45° latitude on the Sun's surface. As the cycle progresses, they appear at lower and lower latitudes, until 5° to 10°, at the end of the cycle. This tendency is revealed on a → butterfly diagram. Although named after Gustav Spörer, the "law" was first discovered by Richard Carrington.

→ Sporer minimum; → law.

A mark on a surface differing sharply in color from its surroundings. → sunspot; → Great Red Spot.

M.E. spotte "a spot, blot, patch;" M.Du. spotte "spot, speck."

Lak(k), lak(k)é "spot, stain."

1a) To draw, stretch, or open out, especially over a flat surface, as something rolled or folded (often followed by out).
1b) To stretch out or unfurl in the air, as folded wings, a flag, etc.
2) An act or instance of spreading; expansion, extension, or diffusion (Dictionary.com).

M.E. spreden, from O.E. sprædan "to spread, extend," cf. Dan. sprede, O.Swed. spreda, M.Du. spreiden, O.H.G. and Ger. spreiten "to spread," from PIE root *sper- "to strew."

Gostardan "to spread; to diffuse, to expand," from Mid.Pers. wistardan "to extend; to spread;" Proto-Iranian *ui.star-; Av. vi- "apart, away from, out" (O.Pers. viy- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + Av. star- "to spread," starati "spreads" (cf. Skt. star- "to spread out, extend, strew," strnati "spreads;" Gk. stornumi "I spread out," strotos "spread, laid out;" L. sternere "to spread;" Ger. Strahlung "radiation," from strahlen "to radiate," from Strahl "ray;" from M.H.G. strāle; from O.H.G. strāla "arrow," stripe; PIE base *ster- "to spread").

1) The season that starts when the Sun, during its apparent yearly motion, attains the celestial longitude 0 degree in the Northern Hemisphere and 180 degrees in the Southern Hemisphere. The current length of the spring season, around the year 2000, is about: spring 92.76 days.
2) A surface flow of groundwater which occurs any time the water table intersects the surface. Related concept → source = xan (خن).
3) An elastic device, usually a twisted piece of metal, that returns to its original shape when it is pressed or stretched, used chiefly to exert constant tension or absorb movement.

1) From the verb M.E. springen; O.E. springan "to leap, burst forth, fly up;" the notion is of the "spring of the year," when plants "spring up" cf. Du., Ger. springen.
2) Similarly from the verb, as above, M.E. spring(e); O.E. spring, spryng; cf. O.H.G., Dan., Sw. spring.
3) From the verb spring, as above.

1) Bahâr, from Mid.Pers. wahâr "spring;" O.Pers. vāhara- "spring time," θūra-vāhara- "name of a spring month;" Av. vaηhar "spring;" cf. Skt. vasara- "relating or appearing in the morning;" Gk. ear "spring;" L. uēr "spring," vernus "of spring;" O.N. vār "spring;" Lith. vasara "summer;" O.C.S. vesna "spring."
2) Cešmé "spring, source," from Mid.Pers. cašmag "spring, source," supposed to be related to cašm, cešm→ eye.
3) Fanar, from Turk fanâr.

A characteristic of a spring which is defined as the ratio of the force affecting the spring to the displacement caused by the force. In other words, the spring constant is the force applied if the displacement in the spring is unity. It is expressed by the equation k = -F/x (from → Hooke's law), where F = force applied, x = displacement by the spring. The spring constant is usually expressed in Newton per meter (N/m).

→ spring; → force.

→ vernal equinox.

→ spring; → equinox.

Tide that occurs when the → Earth, the → Sun, and the → Moon are in a line. This happens approximately twice a month, around → new moon and → full moon. In such a condition, known as → syzygy, the tidal force due to the Sun reinforces that due to the Moon. Spring tides have nothing to do with the season spring. The name derives from the meaning "a leap, jump, bound, rise."

Spring "a leap, jump, or bound;" M.E. springen, from spring O.E. springan "to leap, fly up; spread, grow;" cognates: O.N., O.Fris. springa, M.Du. springhen, O.H.G. springan, Ger. springen, from PIE *sprengh-, form *spergh- "to move, hasten, spring" (Skt. sprhayati "desires eagerly," Gk. sperkhesthai "to hurry."

Mehkešandak "high tide," from meh-, → high, + kešand, → tide.

1) To scatter (a liquid, powder, etc.) in drops or particles.
2) The act or an instance of sprinkling.

M.E. sprenklen (v.); cognate with Du. sprenkelen, Ger. sprenkeln; O.E. sprengan "to sprinkle, make (something) spring, scatter."

Peškidan, from (Malâyeri, Hamedâni) peška "sprinkle, water drop," variant of (Dehxodâ) pašang "sprinkle," pešanjidan "to sprinkle, spray;" (dialects of Khorâsân, Bandar Abbâs, Kermân, Dari Kermân, Lâ) pešang "spraying;" ultimately from Proto-Ir. *pati-haic- from *haic- "to pour (out), moisten);" cf. Av. patihaēc- "to sprinkle all over, pour on;" Mid.Pers. pšnc-/paššinj- "to sprinkle;" related to Pers. xēs, xis, hēs "wet;" O.H.G. sīhan "to sift;" O.E. sēon "to flow away, to sift;" PIE root *seik^w- "to pour" (Cheung 2007).

A very brief, predominantly red, luminous glow, that occurs in the → mesosphere. Sprites occur high above large → thunderstorms and last only a few milliseconds. They have a lump of light on top and numerous tendrils descending downward. Sprites can shoot about 90 to 95 km up into the atmosphere, reaching the → ionosphere, and extend 160 km across. They are very difficult to see, and for that reason were not reliably recorded until 1989. See also → elve; → blue jet.

Sprite "elf, fairy, eerie, ghost-like quality," so named by D. Sentman et al. (1995, Geophys. Res. Let, 22, 1205) because of the fleeting nature of sprites; M.E., from O.Fr. esprit "spirit," from L. spiritus "soul, vigor, breath," related to spirare "to breathe."

Farfadé, from Fr. farfadet, of dialectal origin, derived from fado "fairy."

1) A pointed device on the heel of a rider's boot used to urge on the horse.
2) A sharp horny part on the leg of some birds.
3) Geology: A lateral lower mountain ridge descending from the mountain or the main ridge crest.
4) Mining: A small vein branching from a main one.
5) → Orion Spur.

M.E. spur, from O.E. spura, spora "metal implement worn on the heel to goad a horse," akin to M.Du. spore, Du. spoor, O.H.G. sporo, Ger. Sporn "spur."

Šaxâk, from šax "hard ground, especially on the summit or at the skirt of a mountain; anything hard; a mountain," + noun/nuance suffix -âk.
Mehmiz "a spur, a goad," loan from Ar.

To emit particles, sparks, etc., forcibly or explosively, especially accompanied by sputtering sounds.

Originally "to spit with explosive sounds," cognate with Du. sputteren, W.Fris. sputterje.

Osparândan, literally "to throw out," from os- "out," → ex-, + parândan "to eject," transitive verb of paridan "to fly" (from Mid./Mod.Pers. par(r) "feather, wing," Av. parəna- "feather, wing;" cp. Skt. parna "feather," E. fern; PIE *porno- "feather").

The ejection of charged particles or atoms by a solid or liquid surface which undergoes collision with high-energy ions.

Verbal noun of → sputter.

A sudden, violent gust of wind, often accompanied by rain, snow, or sleet. A sudden increase of the mean wind speed which lasts for several minutes at least before the mean wind returns to near its previous value. It is often accompanied by rain or snow.

Probably from a Scand. source (cf. Norw. skval "sudden rush of water," Sw. skvala "to gush, pour down").

Bâdzad, from bâd, → wind + zad past stem of zadan "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 *g^when- "to strike, kill").

1) A rectangle having all four sides of equal length.
2) The second power of a quantity, expressed as a² = a × a, where a is the quantity. → inverse square law.

M.E., from O.Fr. esquire "a square, squareness," from V.L. *exquadra, from *exquadrare "to square," from L. → ex- "out" + quadrare "make square," from quadrus "a square," from quattuor→ four.

Câruš, from Av. caθruša- "four sides (of a four-sided figure)", from caθru- "four," Mod.Pers. cahâr, câr "four" + uša- "angle," Mod.Pers. guš, gušé.

A solid angle whose cone is a tetrahedral pyramid with an angle between its edges equal to 1°. 1 square degree = 3.046 x 10^-4 sr = 2.424 x 10^-5 solid angle of a complete sphere.

→ square; → degree.

An international project to construct a highly sensitive radio interferometer array operating between 0.15 and 20 GHz with an effective collecting area of one square kilometer. The number of individual telescopes will be 2000 to 3000. SKA will have a sensitivity 100 times higher than that of today's best radio telescopes and an angular resolution < 0.1 arcsec at 1.4 GHz. The site will be selected in 2012 and early science with Phase 1 is scheduled for from 2016 on. See also the SKA homepage.

→ square; → kilometer; → array.

A → matrix with equal numbers of → rows and → columns (i.e., an n × n matrix).

→ square; → matrix.

A large → asterism of four stars, approximately square in shape, in the northern sky. Three of the stars, → → Markab, → Scheat, and → Algenib, belong to the constellation → Pegasus. The fourth, → Alpheratz, was lost to Pegasus when the constellation boundaries were formalised, and now lies just within the borders of → Andromeda.

→ square; → Pegasus.

Chahârguš, → tetragon; → Pegasus.

Quantity which when multiplied by itself produces another quantity.

→ square; → root.

An oscillation which alternatively assumes, for equal lengths of time, one or two fixed values.

→ square; → wave.