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: 466 Search : pH
physics
  فیزیک   
fizik (#)

Fr.: physique   

The science that deals with matter and energy and their interactions.

M.E. fisyk(e), phisik(e), from O.Fr. fisique, from L. physica (fem. sing.) "study of nature," from Gk. physike episteme "knowledge of nature," from fem. of physikos "pertaining to nature," from physis "nature," from phyein "to bring forth, produce, make to grow," Gk. phy- "to become;" L. fui "I was," futurus "that is to be, future;" Ger. present first and second person sing. bin, bist; E. to be; O.Ir. bi'u "I am;" Lith. bu'ti "to be;" Rus. byt' "to be."

Loan from Fr. physique, as above.

physisorption
  فیزی-شمش   
fizi-šameš

Fr.: physisorption   

A kind of → adsorption in which the forces involved are → intermolecular  → van der Waals forces. Same as → physical adsorption. See also → chemisorption.

Physi-, from → physical; → sorption.

plane-parallel atmosphere
  هواسپهر ِ پراسو-تخت، جو ِ ~   
havâsepehr-e parâsu-taxthâ, javv-e ~

Fr.: atmosphère plan-parallèle   

An approximation used in many stellar atmosphere models that depict the atmosphere as being only one-dimensional and bounded at the top and bottom by horizontal plane surfaces normal to the direction of gravity.

plane; → parallel; → atmosphere.

planetary physics
  فیزیک ِ سیارگان   
fizik-e sayyâregân (#)

Fr.: physique des planètes   

The study of the structure, composition, as well as physical and chemical properties of the planets of the solar system, including their atmospheres and their immediate cosmic environment.

planetary; → physics.

planisphere
  تخت-سپهر، تخت-کره   
taxt-sepehr, taxt-koré

Fr.: planisphère   

A projection or representation of the whole or a part of a sphere on a plane. In particular, a polar projection of the celestial sphere or the Earth on a plane.

plani-; → sphere.

planispheric
  تخت-سپهری، تخت-کره‌ای   
taxt-sepehri, taxt-kore-yi

Fr.: planisphérique   

Of or relating to → planisphere.

planisphere + → -ic..

planispheric astrolabe
  اسطرلاب ِ تخت-سپهری، ~ کره‌ای   
ostorlâb-e taxt-sepehri, ~ kore-yi

Fr.: astrolabe planisphérique   

The most common form of the → astrolabe in which both the → celestial sphere and the observer's horizon are projected on to one or more plane surfaces by means of the stereographic projection. See also → universal astrolabe and → particular astrolabe.

planispheric; → astrolabe.

plasma physics
  فیزیک ِ پلاسما، پلاسمافیزیک   
fizik-e plâsmâ (#), plâsmâ fizik (#)

Fr.: physique des plasmas   

The study of the physical properties of the various forms of plasmas and their processing.

plasma; → physics.

plasmasphere
  پلاسماسپهر   
pelâsmâsepehr

Fr.: plasmasphère   

In the magnetosphere, a region of relatively cool (low energy) and dense plasma that may be considered an outer extension of the ionosphere with which it is coupled. Like the ionosphere, the plasmasphere tends to co-rotate with the Earth.

plasma + → sphere.

Poincaré sphere
  کره‌ی ِ پو‌آنکاره   
kore-ye Poincaré

Fr.: sphère de Poincaré   

A representation that permits an easy visualisation of all different states of → polarization of a vector wave. The equator represents → linear polarization; the north pole corresponds to right-circular and the south pole to left- → circular polarization.

Named after Henri Poincaré (1854-1912), French mathematician and theoretical physicist, and a philosopher of science; → sphere.

potentially hazardous asteroid (PHA)
  سیارک ِ توندانه آپه‌ناک   
seyyârak-e tavandâné âpenâk

Fr.: astéroïde potentiellement dangereux   

An asteroid that could make a threatening close approach to the Earth. In technical terms a PHA is defined as having an → absolute magnitude of 22 or brighter and an → Earth Minimum Orbit Intersection Distance (MOID) of less than 0.05 → astronomical unit or 7.5 million km.

potentially; → hazardous; → asteroid.

prolate spheroid
  کره‌وار ِ کشیده   
korevâr-e kešidé

Fr.: sphéroïde allongé   

An ellipsoid produced by rotating an ellipse through 360° about its major axis. → oblate spheroid.

prolate; → spheroid.

pulsar magnetosphere
  مغنات‌سپهر ِ پولسار   
meqnâtsepehr-e pulsâr

Fr.: magnétosphère de pulsar   

A dense zone of magnetized → plasma surrounding a → pulsar. The magnetosphere, lying between the surface of the → neutron star and the → light cylinder, corotates with the pulsar like a rigid body under the effect of strong magnetic field. The magnetosphere's thickness is determined by the constraint that the corotation velocity of its upper surface should not exceed the → speed of light.

pilsar; → magnetosphere.

quantum phase transition (QPT)
  گذرش ِ فاز ِ کو‌آنتومی   
gozareš-e fâz-e kuântomi

Fr.: transition de phase quantique   

A phase transitions that occurs at zero temperature as a function of a non-thermal parameter like → pressure, → magnetic field, or → chemical composition. In contrast to ordinary → phase transitions, which are associated with passage through a critical temperature, quantum phase transitions are associated with → quantum fluctuations, a consequence of → Heisenberg's uncertainty principle. For example, see → Bose-Einstein condensation.

quantum; → phase; → transition.

quark-hadron phase transition
  گذرش ِ فاز ِ کو‌آرک-هادرون   
gozareš-e fâz-e kuârk-hâdron

Fr.: transition de phase quark-hadron   

A phase transition, predicted by cosmological models, to have occurred at approximately 10-5 seconds after the Big Bang to convert a plasma of free quarks and gluons into hadron.

quark; → hadron; → phase; → transition.

radiative phase
  فاز ِ تابشی   
fâz-e tâbeši

Fr.: phase radiative   

For a → supernova remnant (SNR), same as the → snowplow phase.

radiative; → phase.

radiography
  پرتونگاری   
partow-negâri (#)

Fr.: radiographie   

The process of producing an image on a sensitive surface by radiation such as X-rays or gamma rays passing through an object.

radio + → -graphy.

Rasalhague (α Ophiuchi)
  رأس‌الحیه   
ra's-el-hayyé (#)

Fr.: Rasalhague   

The brightest star (V = 2.08) in the constellation → Ophiuchus. Rasalhague is a → giant star of type A5 lying 47 light-years from Earth. It has a faint, very close companion only 0''.5 away, 7 A.U., that orbits with a period of 8.7 years.

Rasalhague, from Ar. Ra's al-Hayyah (رأس‌الحیه), literally the "head of the snake," from ra's "head" + Hayyah "snake," referring to the creature in Gk. mythology.

reducing atmosphere
  جوّ ِ باز‌هازنده، هواسپهر ِ ~   
javv-e bâzhâzandé, havâsepehr-e ~

Fr.: atmosphère réductrice   

1) An atmospheric condition in which oxidation is prevented by removal of oxygen and other oxidating gasses or vapours. Usually nitrogen or hydrogen gas is used in order to produce specific effects, e.g. on ceramic wares being fired.
2) An atmosphere of a planet or moon which has a high hydrogen content, either in the form of free hydrogen or hydrogen-containing compounds, such as methane or ammonia. The early atmosphere of Earth is thought to be reducing, dominated by carbon dioxide.

Reducing verbal adj. of → reduce; → atmosphere.

Rho Ophiuchi Cloud
  ابر ِ رو-مارافسا   
abr-e rho Mâr-afsâ

Fr.: Nuage de rho Ophiuchi   

A complex region of molecular and dust clouds containing emission and reflection nebulae near the star ρ Oph in the constellation → Ophiuchus. It is one of the closest star forming regions, some 400 light-years distant. Recent studies using the latest X-ray and infrared observations reveal more than 300 young stellar objects within the large central cloud. Their median age is only 300,000 years.

Rho, Gk. letter; → Ophiuchus; → cloud.

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