An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 544
teranzistor (#)

Fr.: transistor   

An active semiconductor device with a small low-powered solid-state electronic device consisting of a semiconductor and three or more electrodes, used as an amplifier and rectifier and frequently incorporated into integrated circuit chips. Although much smaller in size than a vacuum tube, it performs similar functions without requiring current to heat a cathode.

From trans-, from → transfer + -istor, from → resistor; → resistance.

gozar (#)

Fr.: transit   

1) An event where one astronomical object appears to move across the face of another. As seen from Earth, the planets Venus and Mercury are seen to transit the Sun. We can also observe natural satellites transit the face of their host planet. Similarly exoplanets have been observed to transit their host stars. See also → planetary transit, → transit method.
2) The passage of a heavenly body across the meridian of a given location.

M.E., from L. transitus, p.p. of transire "to go or cross over," from → trans- "across" + ire "to go."

Gozar "passage, transit, passing," from gozaštan "to pass, cross, transit," variant gozâštan "to put, to place, let, allow;" Mid.Pers. widardan, widâštan "to pass, to let pass (by);" O.Pers. vitar- "to pass across," viyatarayam "I put across;" Av. vi-tar- "to pass across," from vi- "apart, away from" (O.Pers. viy- "apart, away;" Av. vi- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + O.Pers./Av. tar- "to cross over;" → trans-.

transit circle
  پرهونِ گذر، ~ِ نیمروزانی   
parhun-e gozar, ~ nimruzâni

Fr.: cercle méridien   

An observing instrument provided with a graduated vertical scale, used to measure the declinations of heavenly bodies and to determine the time of meridian transits. Same as → meridian circle.

transit; → circle; nimruzâni, adj. of nimruzân, → meridian.

transit instrument
  سازال ِ گذر ِ نیمروزانی   
sâzâl-e gozare nimruzâni

Fr.: instrument méridien   

An instrument mounted so as to allow it to be pointed only at objects in the sky crossing the local meridian. Also known as → transit telescope.

transit; → instrument.

transit method
  روش ِ گذر   
raveš-e gozar

Fr.: méthode du transit   

A method for detecting → exoplanets that is based on the decrease of star → brightness when the exoplanet passes in front of its star. As the planet transits, a portion of the light from the star is blocked causing a decrease in the → magnitude of the star. The amount of decrease (typically between 0.01% and 1%) depends on the sizes of the star and the planet. The duration of the transit depends on the planet's distance from the star and the star's mass. This change must be periodic if it is caused by a planet. In addition, all transits produced by the same planet must be of the same change in brightness and last the same amount of time. Once detected, the planet's distance from its star can be calculated from the period and the mass of the star using → Kepler's third law of planetary motion. The size of the planet is found from the depth of the transit and the size of the star. From the orbital size and the temperature of the star, the planet's characteristic temperature can be calculated. Knowing the star's mass and size, the planet's size and distance can be estimated. Also the composition of a → transiting planet's atmosphere can, in principle, be determined.

transit; → method.

transit of Mercury
  گذر ِ تیر   
gozar-e Tir

Fr.: transit de Mercure   

The crossing the face of the Sun by the planet Mercury, as seen from Earth. Because the plane of Mercury's orbit is not exactly coincident with the plane of Earth's orbit, Mercury usually appears to pass over or under the Sun. On the average it occurs 13 times each century when the Earth is near the → line of nodes of Mercury's orbit. The three last transits were on 2003 May 07, 2006 November 08, and 2016 May 09. The next one will be on 2019 November 11. The first observation of a transit of Mercury was on November 7, 1631 by Pierre Gassendi. On June 4, 2014 NASA's Mars rover Curiosity photographed a transit of Mercury, marking the first time such a phenomenon has ever been imaged from the surface of a planet other than Earth. See also → black drop.

Mercury; → transit.

transit of Venus
  گذر ِ ناهید   
gozar-e Nâhid

Fr.: transit de Vénus   

A rare phenomenon that happens when the planet Venus passes directly between the Sun and Earth and is therefore seen against the solar disk. Such a passage occurs every 122 or 105 years and when it happens the next occurrence is after 8 years. Only seven transits of Venus have occurred since the invention of the telescope: in 1639, 1761, 1769, 1874, 1882, 2004, and 2012. The next one will be in 2117. The reason for this rarity is that the Earth and Venus do not orbit the Sun in the same plane. Their orbital planes have a relative inclination of about 3°. The first observation of the Venus transit was in 1639 by the English Jeremiah Horrocks (1618-1641). See also → black drop.

Venus; → transit

transit telescope
  دوربین ِ گذر ِ نیمروزانی، تلسکوپ ِ ~ ِ ~   
durbin-e gozar-e nimruzâni, teleskop-e ~ ~

Fr.: lunette méridienne   

Same as → transit instrument.

transit; → telescope.

transit time
  زمان ِ گذر   
zamân-e gozar

Fr.: temps de passage   

The time interval between the release of an electron at the photocathode and the arrival of an electron at the anode. Transit time is not a single-valued quantity, but has a bell-shaped distribution.

transit; → time.

transiting planet
  سیاره‌ی ِ درگذر   
sayyâre-ye dar gozar

Fr.: planète en transit   

A planet that passes in front of its star directly between Earth and the star. The → transit method is used for detecting → exoplanets around stars.

transit; → planet.

TRAnsiting Planets and PlanetesImals Small Telescope (TRAPPIST)


A Belgian facility devoted to the detection and characterization of → exoplanets and to the study of → comets (→ transiting planet) and other → small solar system bodies. It consists of two 60 cm robotic telescopes located at the → European Southern Observatory, → La Silla, in Chile and at Oukaïmden Observatory in Marroco.

transit; → planet; → planetesimal; → small; → telescope.


Fr.: transition   

1) Passage from one position, state, stage, subject, concept, etc., to another.
2) A change between phases such as solid to liquid or liquid to gas.
3) A change in the → energy level or state of an atom or nucleus. → atomic transition, → bound-bound transition, → bound-free transition, → cascade transition, → discrete transition, → forbidden transition, → hyperfine transition, → nuclear transition, → permitted transition, → phase transition, → quark-hadron phase transition, → radiative transition, → rotational transition, → semi-forbidden transition, → transition disk, → transition function, → transition probability, → vibrational transition.

From L. transitionem (nominative transition) "a going across or over," noun of action from transire "go or cross over," from → trans- "across" + ire "to go."

Gozareš, verbal noun of gozaštan "to transit, pass," → transit, + -eš, → -tion.

transition disk
  گرده‌ی ِ گذرش، دیسک ِ ~   
gerde-ye gozaresh, disk-e ~

Fr.: disque de transition   

The → accretion disk of a → T Tauri star that displays very weak or no → infrared excess at → near infrared wavelengths, but shows strong excess at → intermediate infrared and longer wavelengths. This happens when the hot inner dust disk has dissipated whereas the cooler outer disk is still intact.

transition; → disk.

transition function
  کریای ِ گذرش   
karyâ-ye gozareš

Fr.: fonction de transition   

The → probability of finding the → Universe in a → state labelled X2 at a time t2, if it was in a state X1 at an earlier time t1.

transition; → function.

transition probability
  شوانایی ِ گذرشی   
šavânâyi-ye gozareši

Fr.: probabilité de transition   

The probability that a quantum-mechanical system will make a transition from a given initial state to a given final state.

transition; → probability.

transitional flow
  تچان ِ گذرشی   
tacan-e gozareši

Fr.: flux de transition   

In fluid mechanics, a flow composed of → laminar and → turbulent flows, for which the → Reynolds number is between 2300 and 4000.

transition; → flow.

  ۱) تراجاییدن؛ ۲) ترازبانیدن   
1) tarâjâyidan; 2) tarâzabânidan

Fr.: 1) translater; 2) traduire   

1a) Mechanics: To subject a body to → translation.
1b) Math.: To perform a → translation.
2a) To turn from one language into another.
2b) To convert computer data to a different form according to an → algorithm.

M.E. translaten, from L. translatus, from → trans- "across" + latus suppletive p.p. of ferre "to carry;" cognate with Pers. bordan "to carry, transport;" Mid.Pers. burdan; O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive);" Skt. bharati "he carries;" Gk. pherein "to carry;" PIE base *bher- "to carry."

1) Tarâjâyidan, from tarâ-, → trans- "across" + "place" (from Mid.Pers. giyag "place;" O.Pers. ā-vahana- "place, village;" Av. vah- "to dwell, stay," vanhaiti "he dwells, stays;" Skt. vásati "he dwells;" Gk. aesa (nukta) "to pass (the night);" Ossetic wat "room; bed; place;" Tokharian B wäs- "to stay, wait;" PIE base *ues- "to stay, live, spend the night") + -idan infinitive suffix.
2) Tarâzabânidan, from tarâ-, as above, + zabân "tongue; language" (Mid.Pers. uzwân "tongue; language;" O.Pers. hzanm, hizānam "tongue;" Av. hizuua-, hizū- "tongue;" cf. Skt. jivhā- "tongue;" L. lingua "tongue, speech, language;" O.Ir. tenge; Welsh tafod; Lith. liezuvis; O.C.S. jezyku; M.Du. tonghe; Du. tong; O.H.G. zunga; Ger. Zunge; Goth. tuggo; PIE base *dnghwa-) + -idan infinitive suffix. The similarity of tarâzabân with the classical Pers. terms tarzafân, tarzabân "a person who translates orally from one language into another; eloquent" is intriguing: from tar- variant of tarâ- + zafân, zabân "tongue, language"?!

  ۱، ۲) تراجایش؛ ۳) ترازبانش   
1, 2) tarâjâyeš; 3) tarâzabâneš

Fr.: translation   

1) Mechanics: A motion of a rigid body characterized by parallel paths of all particles. Every point of the body in translation has the same velocity and acceleration at any particular instant. The translation motion may be rectilinear or curvilinear.
2) Math.: A transformation which moves all points on a plane through the same distance in the same direction. The object and its image are congruent. Also a function obtained from a given function by adding the same constant to the value of each of its variables.
3) A rendering from one language into another; a version of such a rendering.

Verbal noun of → translate.

Tarâjâyeš, verbal noun of tarâjâyidan, tarâzabâneš, verbal noun of tarâzabânidan, → translate.


Fr.: translucide   

The quality of a material that allows light to pass through, but only diffusely, so that objects on the other side cannot be clearly distinguished. → transparent.

From L. translucent-, p.p. of translucere "to shine through," from → trans- + lucere "to shine," related to lux "light," lucidus "clear," luna, "moon;" Fr. lumière "light;" cf. Pers. ruz "day," rowšan "bright, clear," rowzan "window, aperture;" foruq "light," afruxtan "to light, kindle;" Mid.Pers. rôšn "light; bright, luminous," rôc "day;" O.Pers. raucah-rocânak "window;" O.Pers. raocah- "light, luminous; daylight;" Av. raocana- "bright, shining, radiant;" akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" O.E. leoht, leht, from W.Gmc. *leukhtam (cf. O.Fris. liacht, M.Du. lucht, Ger. Licht), from PIE *leuk- "light, brightness."

Tarâtâb, from tarâ-, → trans- + tâb present stem of tâbidan "to shine," variants tâftan "to shine," tafsidan "to become hot;" Mid.Pers. tâftan "to heat, burn, shine;" taftan "to become hot;" Parthian t'b "to shine;" Av. tāp-, taf- "to warm up, heat," tafsat "became hot," tāpaiieiti "to create warmth;" cf. Skt. tap- "to heat, be/become hot; to spoil, injure, damage; to suffer," tapati "burns;" L. tepere "to be warm," tepidus "warm;" PIE base *tep- "to be warm."

translucent cloud
  ابر ِ تراتاب   
abr-e tarâtâb

Fr.: nuage translucide   

A type of → interstellar medium cloud where → carbon (C), in → ionized atomic form and protected from → interstellar radiation, transforms into neutral atomic or molecular form. The chemistry in this regime is qualitatively different than in the → diffuse molecular clouds, both because of the decreasing electron fraction and because of the abundance of the highly reactive C atoms. The translucent cloud regime is the least well understood of all the cloud types. This is partly because of a relative lack of observational data, but also because theoretical models do not all agree on the chemical behavior in this transition region. In some models, there is a zone where the abundance of C exceeds that of C+ and CO; in others the peak abundance of C falls below that of C+ and CO. To cope with this uncertainty, Snow & McCall (2006) propose a working definition of translucent cloud material as gas with C+ fraction < 0.5 and CO fraction < 0.9. This definition reflects the fact that C+ is no longer the dominant form of carbon as it converts to neutral or molecular form, but also excludes the → dense molecular clouds, where carbon is almost exclusively CO (Snow & McCall, 2006, ARA&A 44, 367).

translucent; → cloud.

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