An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1965 Search : ion
submillimeter radiation
  تابش ِ زیر-میلیمتری   
tâbeš-e zir-milimetri

Fr.: rayonnement sub-millimétrique   

That part of the → electromagnetic radiation with a → wavelength beyond 300 → microns.

submillimeter; → radiation.


Fr.: soumission   

An act or instance of submitting. The condition of having submitted. → submit

Verbal noun of → submit.


Fr.: souscription   

1) A sum of money given or pledged as a contribution, payment, investment, etc. 2) The right to receive a periodical for a sum paid, usually for an agreed number of issues (

subscribe; → -tion.


Fr.: soustraction   

The operation of finding the difference between two numbers or quantities.

Verbal noun of → subtract.

pišnehâd (#)

Fr.: suggestion   

1) The act of suggesting.
2) The state of being suggested.
3) Something suggested, as a piece of advice (

Verbal noun of → suggest.

supergranulation cell
  یاخته‌ی ِ اَبَر-دانه‌بندی   
yâxte-ye abar-dâne-bandi

Fr.: cellule de supergranulation   

One of a number of large convective cells (about 15,000-30,000 km in diameter) in the solar photosphere, distributed fairly uniformly over the solar disk, that last longer than a day.

super-; → granulation; → cell.


Fr.: superion   

An ion which is responsible for the existence of a strong → P Cygni profile observed in many early O stars. Since the → effective temperature of the star is too low to produce such an ion appreciably, the ion is termed a superion. For example, the ion O5+ which is at the origin of a strong O VI λλ1031, 1038 P Cygni profile observed in many O stars. Similarly, the lines due to N V λλ1238, 1242 belong to the superion category, while in later spectral types C IV λλ1548, 1552 also falls into this category. Initial modeling of the → ultraviolet line superions assumed the → stellar winds were smooth and homogeneous. However it is now generally accepted that the winds are (→ clumped wind), and this can have a profound influence on the formation of the superion profiles. We know that the strength of lines due to the superions is strongly influenced by the → interclump medium. Indeed, the interclump medium may be more important for producing the lines than are the clumps -- this is simply a consequence of the higher ionization in the interclump medium which occurs because of its lower density (see D. John Hillier, 2020,, and references therein).

super-; → ion.

superior conjunction
  هم‌ایستان ِ زبرین   
hamistân-e zabarin

Fr.: conjonction supérieure   

The conjunction of a planet with the Sun which occurs when the planet is beyond the Sun. → inferior conjunction.

superior; → conjunction.

superior culmination
  بالست ِ زبرین   
bâlest-e zabarin

Fr.: culmination supérieure   

The meridian transit of a star between the celestial pole and the south point of the horizon. Same as → upper culmination. → inferior culmination.

superior; → culmination.

superluminal motion
  جنبش ِ اَبَر-نوری   
jonbeš-e abar-nuri

Fr.: mouvement superluminal   

Apparent proper motion exceeding the velocity of light seen toward certain astronomical objects, such as the jets of radio galaxies and quasars. However, these jets are not actually moving at speeds in excess of the speed of light: the apparent superluminal motion is a projection effect caused by objects moving near the speed of light and at a small angle to the line of sight.

super-; luminal, from → lumen; → motion.

Jonbeš, → motion; abarsuper-; nur, → light.

supernova explosion
  اُسکفت ِ اَبَر-نو‌اختر   
oskaft-e abar-now-axtar

Fr.: explosion de supernova   

The very short and violent phenomenon that occurs when a star undergoes → core collapse or → thermonuclear runaway.

supernova; → explosion.


Fr.: superposition   

1) The act of placing upon; the state of being placed upon.
2) Math. The act of placing (one geometric figure) over another so that all like parts coincide.

super- + → position.

Barhamneheš, from bar- "on, upon, up" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + -ham- "together, with," → syn-, + neheš, → position.

superposition principle
  پروز ِ برهم‌نهش   
parvaz-e barhamneheš

Fr.: principe de superposition   

1) Math.: The principle concerned with homogeneous and non-homogeneous → linear differential equations, stating that two or more solutions to a linear equation or set of linear equations can be added together so that their sum is also a solution.
2) One of the most fundamental principles of → quantum mechanics which distinctly marks the departure from classical concepts. It holds that any linear superposition of → wave functions is also a possible wave function. Simply put, the state of an object is all its possible states simultaneously, as long as we do not look to check. It is the measurement itself that causes the object to be limited to a single possibility. The superposition principle is rooted in the linearity of → Schrödinger's equation. Hence if two solutions of the wave function, ψ1 and ψ2, are known, other solutions, of the form: ψ = a1ψ1 + a2ψ2 also represent possible states of the system.

superposition; → principle.


Fr.: super-saturation   

The process whereby the amount of → water vapor in the air exceeds that needed to → saturate. In other words, the condition of air in which the → humidity is above the level required for saturation at a given temperature (i.e. the → relative humidity is greater than 100%). When the temperature drops below freezing, this can lead to a situation where more water vapor is present in the air than the air can hold. At every temperature, there is a maximum amount of water vapor that can be supported in the air. The higher the temperature, the more water vapor can be accommodated. But if the air that is already at 100% relative humidity is cooled then it becomes supersaturated, and this situation is unstable. As a result, the excess water vapor crystallizes out, either into water droplets or directly into ice.

super-; → saturation.


Fr.: suppression   

The act of suppressing; the state of being suppressed. → Compton suppression, → zero suppression.

suppress; → -tion.

surface tension
  تنش ِ رویه‌ای   
taeš-e ruye-yi

Fr.: tension superficielle   

The inward → attraction of the → molecules at the → surface of a → liquid. The reason is that the molecules at the surface do not have other like molecules on all sides of them and consequently they cohere more strongly to those directly associated with them on the surface. Also called surface energy and capillary forces.

surface; → tension.


Fr.: surjection   

A mapping f of a set A onto a set B in such a way that every b element of B is the image of at least one element a of A. In other words, for any element b of B, the equation f(a) = b yields at least one solution. Allso called → surjective mapping.

From → sur- + → injection.


Fr.: suspicion   

1) The state of mind or feeling of one who suspects.
2) An instance of suspecting something or someone (

M.E., from suspecioun, from O.Fr. suspicion, sospeçon "mistrust, suspicion," from L.L. suspectionem "mistrust, suspicion, fear," noun of state from past participle stem of L. suspicere "to look up at," → suspect.

Verbal noun from bargâsidan, → suspect.

symmetric relation
  بازانش ِ همامون   
bâzâneš-e hamâmun

Fr.: relation symétrique   

A relation between two quantities such that the first is to the second as the second is to the first. In symbols: a R b = b R a. For example, multiplication is an operation with a symmetric relation between the factors: 5 x 3 = 3 x 5.

symmetric; → relation.

synchronous rotation
  چرخش ِ همگام   
carxeš-e hamgâm (#)

Fr.: rotation synchrone   

Of a body orbiting another, where the orbiting body takes as long to rotate on its axis as it does to make one orbit. Therefore it always keeps the same hemisphere pointed at the body it is orbiting. Both bodies are tidally locked (→ tidal locking). This phenomenon is a natural consequence of → tidal braking. Synchronous rotation is common throughout the → solar system. It is found among the satellites of → Mars (→ Phobos and → Deimos), → Jupiter (most of Jupiter satellites, including the → Galilean Moons) and → Saturn (e.g. → Iapetus). Similarly, → Pluto and its moon → Charon are locked in mutual synchronous rotation, with both of them keeping the same faces towards each other.

synchronous; → rotation.

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