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

A form of fiction that draws imaginatively on scientific knowledge and speculation in its plot, setting, theme, etc. (Dictionary.com).

→ science; → fiction.

Of or pertaining to science or the sciences.
Systematic or accurate in the manner of an exact science.

From M.Fr. scientifique, from M.L. scientificus "pertaining to science," from L. scientia "knowledge," → science, + -ficus "making," from facere "to make." → -ic

Dâneši, dânešik, from dâneš, → science + -i, -ik, → ic.

An agreement by competent observers of a series of observations of the same phenomena. From time to time scientific facts are revised by additional data (G. Smooth, Lawrence Berkeley Lab website).

→ scientific; → fact.

The process by which scientists, collectively and over time, endeavor to construct an accurate (that is, reliable, consistent, and non-arbitrary) representation of the world. The scientific method has four steps:
1) Observation and description of a phenomenon or group of phenomena.
2) Formulation of an hypothesis to explain the phenomena. In physics, the hypothesis often takes the form of a causal mechanism or a mathematical relation.
3) Use of the hypothesis to predict the existence of other phenomena, or to predict quantitatively the results of new observations.
4) Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments.
If the experiments bear out the hypothesis it may come to be regarded as a theory or law of nature. If the experiments do not bear out the hypothesis, it must be rejected or modified. What is key in the description of the scientific method just given is the predictive power (the ability to get more out of the theory than you put in) of the hypothesis or theory, as tested by experiment. It is often said in science that theories can never be proved, only disproved. There is always the possibility that a new observation or a new experiment will conflict with a long-standing theory (Frank L. H. Wolfs, University of Rochester).

→ scientific; → method.

A compact format for writing very large or very small numbers. Numbers are made up of three parts: the coefficient, the base and the exponent. For example 3.58 x 10⁴ is the scientific notation for 35,800.

→ scientific; → notation.

The quality of the practices and theories that aim at establishing reproducible regularities in phenomena by using experimental method and providing a clearly formulated description.

→ scientific + → -ity.

An expert in science, especially one of the physical or natural sciences. → scholar.

From → science + -ist an agent noun suffix.

Dânešmand, from dâneš, → science, + -mand suffix of possession.

1) Rapid variation in the brightness, wavelength, and mean position of stars caused by turbulence in the Earth's atmosphere.
2) In radio astronomy, rapid fluctuations in the detected intensity of radiation from compact cosmic radio sources due to disturbances in ionized gas through which the radiation has passed. → interstellar scintillation.

From L. scintillationem (nominative scintillatio), from scintillatus p.p. of scintillare "to send out sparks, to flash," from scintilla "particle of fire, spark."

Susu, from su "light," related to suz "burning," present stem of suxtan; Mid.Pers. sôxtan, sôzidan "to burn," Av. base saoc- "to burn, inflame" sūcā- "brilliance," upa.suxta- "inflamed;" cf. Skt. śoc- "to light, glow, burn," śocati "burns," śoka- "light, flame;" PIE base *(s)keuk- "to shine."

A device for detecting and measuring ionizing radiation by means of flashes produced when the radiation particles strike a sensitive layer of phosphor.

→ scintillation; → counter.

Relating to a constraint or system that does not contain time explicitly. For example, a pendulum with an inextensible string of length l₀ is described by the equation: x² + y² = l₀² is both → holonomic and scleronomous.

From Gk. sclero-, from skleros "hard" + -nomous, → -nomy.

Saxtdâtik, from saxt, → hard, + dâtik, → -nomy.

The Scorpion. A large and impressive constellation in the → Zodiac, which lies between → Libra to the west and → Sagittarius to the east. Scorpius is located in the southern hemisphere near the center of the Milky Way at approximately 17h right ascension, -40° declination. The bright, red star → Antares marks the heart of the scorpion. The constellation contains deep sky objects such as the open clusters M6 and M7, and the globular clusters M4 and M80. Also in the southern end of the constellation there is the open star cluster NGC 6231. Abbreviation: Sco; genitive: Scorpii.

M.E., from O.Fr. scorpion, from L. scorpionem (nominative scorpio), from Gk. skorpios "a scorpion," from PIE base *(s)ker- "to cut," → shear. According to Gk. mythology, the constellation represents a giant scorpion sent forth by the earth-goddess Gaia to kill the giant Orion when he threatened to slay all the beasts of the earth. Orion and the Scorpion were afterward placed amongst the stars as a pair of constellations. The two opponents are never seen in the sky at the same time, for one constellation sets as the other rises. The scorpion's claws were originally formed by Libra.

Každom "scorpion," variants kajdom, gaždom literally "crooked tail," from Mid.Pers. gazdum literally "stinging tail," from gaz present stem of gazidan (also Mod.Pers.) "to sting, to bite" + dum, dumb (Mod.Pers. dom, domb) "tail;" Av. duma- "tail."

The first and the brightest X-ray source in the sky, after the Sun, discovered in 1962. Scorpius X-1 is a low-mass → X-ray binary consisting of a compact object like a → neutron star or a → black hole, and a low-mass stellar companion. The compact object has a mass of 1.4 → solar masses and the companion 0.42 solar masses. The orbital period is 18.9 hours, and the system lies at a distance of about 9,000 → light-years. The X-rays come from → accretion, where material from the companion overflows its → Roche lobe and spirals down onto the compact object. The luminosity results from the transformation of the falling material's → gravitational potential energy to heat by → viscosity in the → accretion disk.

Named such by the discoverers (Giacconi et al. 1962), because it was the first extrasolar → X-ray source of the sky detected in the constellation → Scorpius.

The nearest → OB association to the Sun. It contains several hundred stars, mostly → B stars which concentrate in the three subgroups: Upper Scorpius, Upper Centaurus Lupus, and Lower Centaurus Crux. Upper Scorpius is the youngest subgroup, Upper Centaurus Lupus the oldest subgroup of the association. Isochrone fitting to the Hertzsprung-Russell diagram indicates that the star formation occurred some 5-20 Myr ago. Based on data from the → Hipparcos catalog, it turns out that the Sco-Cen association lies at a distance of 118-145 → parsecs, with the exact value depending on the subgroup of the association. The Sco-Cen association is probably a member of the → Gould Belt (Preibisch & Mamajek, 2008, astro-ph/0809.0407).

→ Scorpius; → Centaurus; → association.

Vision that occurs when the eye is dark-adapted. In scotopic vision, the level of luminance is so low that the retinal cones are not stimulated, and there is no color vision. Same as scotopia; → dark adaptation.

Scotopic, from L. Gk. skoto- combining form of skotos "darkness" + -opia akin to ope "view, look," ops "eye, face;" → vision.

Did, → vision; târiki noun from târik "dark," Mid.Pers. târig "dark," târ "darkness," Av. taθra- "darkness," taθrya- "dark," cf. Skt. támisrâ- "darkness, dark night," L. tenebrae "darkness," Hittite taš(u)uant- "blind," O.H.G. demar "twilight."

1) A large, usually flat surface onto which an image is projected for viewing.
2) The portion of a computer terminal or monitor upon which information is displayed.

M.E. screne; O.Fr. escren "a screen against heat," from M.Du. scherm "screen, cover," or Frank. *skrank "barrier;" cf. O.H.G. skirm, skerm "protection," scrank "barrier;" Ger. Schrank "cupboard."

Pardé, from Mid.Pers. pardag "curtain, veil, covering;" loaned in Armenian partak "veil," and Georgian p'ardag-i "curtain;" cognate with Gk. pelas, pella, L. pellis "skin;" O.E. filmen "thin skin;" PIE root *pel- "to cover."

A character used for on-screen → display. See also → printer font.

→ screen; → font.

The → Coulomb interaction reduced owing to the presence of other electrons. See → shielding effect.

→ screen; → coulomb; → interaction.

Same as → shielding effect.

→ screen; → effect.

A piece of metal, consisting of a threaded and usually tapered shank that has a slotted head by which it is turned into something in order to fasten things together.

M.E. scrwe, screw, from M.Fr. escroue "nut, cylindrical socket," of uncertain origin.

Pic "screw," present stem of picidan "to twist, entwine, coil."

A minor and faint → constellation in the southern sky at 0h 30m → right ascension, 33° south → declination. Its brightest star is variable with a mean magnitude of only 4.31. Sculptor contains the south Galactic pole. It also contains the → Sculptor Dwarf, which is a member of the → Local Group. Abbreviation: Scl; Genitive: Sculptoris.

Sculptor was introduced by Nicolas Louis de Lacaille (1713-1762). He originally named it Apparatus Sculptoris "the sculptor's studio," but the name was later shortened. From L. sculp(ere) "to carve" + a suffix forming personal agent nouns.

Peykartarâš, from peykar "form, figure, body" (from Mid.Pers. pahikar "picture, image;" from O.Pers. patikara- "picture, (sculpted) likeness," from patiy "against" (Av. paiti; Skt. prati; Gk. poti/proti + kara- "doer, maker," from kar- "to do, make, build;" Av. kar-; Skt. kr-; cf. Skt. pratikrti- "an image, likeness, model; counterpart") + tarâš "cutter," from tarâšidan "to cut, hew; scape; shave;" (Mid.Pers. tâšitan "to cut, cleave; create by putting together different elements;" Av. taš- "to cut off, fashion, shape, create," taša- "axe" (Mod.Pers. taš tišé "axe"), tašan- "creator;" cf. Skt. taks- "to fom by cutting, tool, hammer, form," taksan- "wood-cutter, carpenter;" Gk. tekton "carpenter," tekhne "art, skill, craft, method, system;" L. textere "to weave;" PIE *teks- "to fashion").