An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 13 Search : icy

Fr.: anticyclone   

Meteo.: A weather phenomenon associated with atmospheric high pressure. In the Northern Hemisphere an anticyclone rotates in the clockwise direction. The rotation is caused by the movement of colder higher pressure air that is moving away from the poles toward the equator being affected by the rotation of the Earth.

anti-; → cyclone.


Fr.: anticyclonique   

Having a sense of rotation about the local vertical opposite to that of the Earth's rotation. In other words, → clockwise in the Northern Hemisphere, → counterclockwise in the Southern Hemisphere, and undefined at the equator. The opposite of → cyclonic (Meteorology Glossary, American Meteorological Society).

anticyclone; → -ic.

  ۱) فلک ِ تدویر؛ ۲) اپی-چرخه   
1) falak-e tadvir (#); 2) apicarxé

Fr.: épicycle   

1) In → Ptolemaic system, a circular → orbit of a body around a point that itself orbits circularly another point. Such a system was formulated to explain some → planetary orbits in terms of → circular motions in a → geocentric cosmology.
2a) Math.: A circle that rolls, externally or internally on another circle, generating an → epicycloid or → hypocycloid.
2b) In → galactic dynamics models describing the → spiral arms, a → perturbation of simple circular orbits. → epicyclic theory.

epi-; → cycle.

1) Falak-e tadvir, from Ar. falak al-tadwir, from falak "sphere" + tadwir "causing to turn in a circle."
2) → epi-; → cycle.


Fr.: épicyclique   

Of or pertaining to an → epicycle.

epicycle; → -ic.

epicyclic frequency
  بسامد ِ اپی-چرخه‌ای   
basâmad-e apicarxe-yi

Fr.: fréquence épicyclique   

In the → epicyclic theory of Galactic rotation, the frequency at which a star in the → Galactic disk describes an ellipse around its mean circular orbit. The epicyclic frequency relates to the → Oort's constants. In the solar neighborhood the epicyclic frequency is about 32 km s-1 kpc-1.

epicyclic; → frequency.

epicyclic oscillation
  نوش ِ اپی-چرخه‌ای   
naveš-e apicarxe-yi

Fr.: oscillation épicyclique   

In a → disk galaxy, the motion of a star about the orbital → guiding center when it is displaced radially. See also → epicyclic frequency, → epicyclic theory.

epicyclic; → oscillation.

epicyclic theory
  نگره‌ی ِ اپی-چرخه‌ای   
negare-ye apicarxe-yi

Fr.: théorie épicyclique   

The theory that describes the Galactic dynamics, that is the orbits of stars and gas clouds in the → Galactic disk, as well as the spiral → density wave. Formulated by Bertil Lindblad (1895-1965), the epicyclic theory assumes that orbits are circular with small deviations. Star orbits are described by the superposition of two motions: i) a rotation of the star (epicenter) around the Galactic center at the circular angular velocity, Ω, and ii) a retrograde elliptical motion at → epicyclic frequency, κ. The epicyclic motion in the Galactic plane occurs in a retrograde sense to conserve → angular momentum. In general Ω and κ are different and, therefore, orbits do not close. However, seen by an observer who rotates with the epicenter, orbits are closed ellipses.

epicyclic; → theory.


Fr.: épicycloïde   

A curve traced by a point of a circle that rolls on the outside of a fixed circle. This curve was described by the Gk. mathematicians and astronomer Hipparchus, who made use of it to account for the apparent movement of many of the heavenly bodies.

epi-; → cycloid.

  یخی، یخزده   
yaxi, yaxzade

Fr.: glacé, glacial   

Made of, covered with, or containing → ice.

ice + an English suffix of adjectives denoting "characterized by or inclined to."

JUpiter ICy moons Explorer (JUICE)
  پویشگر ِ مانگهای ِ یخی ِ هرمز   
Puyešgar-e Mânghâ-ye Yaxi-ye Hormoz

Fr.: Jupiter ICy moons Explorer   

An interplanetary mission currently in development by the → European Space Agency planned for launch in 2020. It is aimed mainly at in-depth studies of three potentially ocean-bearing satellites, → Ganymede, → Europa, and → Callisto. JUICE will complete a unique tour of the Jupiter system including several flybys of each planet-sized world, culminating with orbit insertion around Ganymede, the largest moon in the Solar System, followed by nine months of operations in its orbit. JUICE will carry the most powerful scientific payload ever flown to the outer Solar System. It consists of 10 state-of-the-art instruments plus one experiment that uses the spacecraft telecommunication system with ground-based instruments.

Jupiter; → icy; → explorer; → moon.


Fr.: périlune   

The point in the orbit of a satellite around the Moon closest to the Moon; opposite of → apocynthion.

peri- + Gk. Cynthia "goddess of the Moon;" → Cynthian.

Pirâmâh, from pirâ-, → peri-, + mâhmoon.

  کاراه، کارراه   
kârâh, kârrâh

Fr.: 1) ligne d'action; 2) politique   

1) A definite course of action adopted for the sake of expediency, facility, etc.
2) A course of action adopted and pursued by a government, ruler, political party, etc. (

M.E. policie "government, civil administration," from O.Fr. policie "political organization, civil administration," from L.L. politia "the state, civil administration," from Gk. politeia "state, administration, government, citizenship," from polites "citizen," from polis "city, state."

Kârâh, contraction of kâr râh, or râh-e kâr literally "way of doing, ~ ~ action," from râh, → way, + kâr "doing, action, → work."

policy maker
kârâh pardâz

Fr.: responsable politique, décideur   

A person responsible for making policy, especially in government (

policy; → make; → -er.