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

An → interplanetary manifestation of a → coronal mass ejection.

→ interplanetary; → coronal; → mass; → ejection.

Particles of dust in the → interplanetary medium. They are left-overs from the beginning of the solar system or from other sources such as sublimating comets. Their existence was first deduced from observations of → zodiacal light.

→ interplanetary; → dust.

Electrically charged particles of the solar wind and gas liberated from comets within the solar system.

→ interplanetary; → gas.

The magnetic field that is carried along with the solar wind and fills the solar system space. It is wound into a spiral structure by the rotation of the Sun. At the Earth's distance from the Sun, it has a strength of about 5 x 10^-5 gauss.

→ interplanetary; → magnetic; → field.

Material existing in the space between solar system planets. It includes interplanetary gas and dust.

→ interplanetary; → matter.

The material contained in the → solar system in the space through which the planets travel. It consists of the smaller objects such as → asteroids, → comets, → meteorites and also a general pervading → interplanetary dust. Moreover a → plasma of charged particles streaming outward from the Sun in the form of the → solar wind contributes to the interplanetary medium.

→ interplanetary; → medium.

Same as → interplanetary medium.

→ interplanetary; → space.

A hypothetical planet, named Vulcan, that once was believed to exist between the Sun and Mercury.

→ intra-; → Mercury; → planet.

Mechanics: For a rotating rigid body not subject to external torque, a plane which is perpendicular to the angular momentum vector of the body, and which is always tangent to its → inertia ellipsoid.

Invariable negation of → variable; → plane.

An airplane moved by → jet propulsion.

→ jet; plane, short for airplane, from Fr. aeroplane, from aero-, → air, + plane feminine of plan "flat, level," from L. planus, perhaps by association with forme plane; apparently coined and first used by Fr. sculptor and inventor Joseph Pline in 1855.

→ jet; havâpeymâ "airplane," from havâ, → air, + peymâ "travelling; traveller," from peymudan, peymâyidan "to travel, traverse, pass over," from Mid.Pers. patmudan, paymudan "to measure (against)," from *pati-māya-. The first element *pati- "against, back" (cf. Mod.Pers. pâd- "against, contrary to;" Mid.Pers. pât-; O.Pers. paity "agaist, back, opposite to, toward, face to face, in front of;" Av. paiti; Skt. práti "toward, against, again, back, in return, opposite;" Pali pati-; Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti). The second element from *mā- "to measure;" O.Pers./Av. mā(y)- "to measure;" cf. Skt. mati "measures," matra- "measure;" Gk. metron "measure;" L. metrum; PIE base *me- "to measure." Apart from peymâ, several other terms in Mod.Pers. are related to this second element, which occurs also as mun, mân, man, mâ, mu, and mây: pirâmun "perimeter," âzmun, âzmây- "test, trial," peymân "measuring, agreement," peymâné "a measure; a cup, bowl," man "a measure weighing forty seers)," nemudan, nemâ- "to show, display," âmâdan, âmây- "to prepare."

A planet that does not have a well-defined → solid  → crust, such as any of the four Solar System outer, gaseous planets: → Jupiter, → Saturn, → Uranus, and → Neptune.

→ Jovian; → planet.

The plane normal to the axis about which the pole of a satellite's orbit → precesses. In his study of Jupiter's satellites, Laplace (1805) recognized that the combined effects of the solar tide and the planet's oblateness induced a "proper" inclination in satellite orbits with respect to Jupiter's equator. He remarked that this proper inclination increases with the distance to the planet, and defined an orbital plane (currently called Laplace plane) for circular orbits that lies between the orbital plane of the planet's motion around the Sun and its equator plane (Tremaine et al., 2009, AJ, 137, 3706).

→ Laplace; → plane.

A name used to describe any planet that is considerably larger and more massive than the Earth, and contains large quantities of hydrogen and helium. Jupiter and Neptune are examples of major planets.

→ major; → planète.

An obsolete name used to describe an → asteroid.

→ minor; → planet.

A stellar system with more than one orbiting planet.

→ multi-; → planet; → system.

A hypothetical → exoplanet covered by a water envelope. The presence of such a planet stems from the implicit assumption of → Habitable Zone temperatures and a liquid water surface.

→ ocean; → planet.

The plane defined by the motion of an object about a primary body.

→ orbital; → plane .

For a curve C at a point p, the limiting plane obtained from taking planes through the tangent to C at p and containing some variable point p' and then letting p' approach p along C.

→ osculating; → plane.

A planet that revolves around the Sun beyond the → asteroid belt, namely → Jupiter, → Saturn, → Uranus, and → Neptune.

→ out; → planet.

1) (n.) a flat or level surface.
2) (adj.) Of or pertaining to planes or plane figures.

1) From L. plantum "flat surface," noun use of adj. planus "flat, level, plain."
2) From L. planus, as above.

1) Hâmon, variant of hâmun "plain, level ground;" Mid.Pers. hâmôn "level, flat;" Proto-Iranian *hāma-van-, from *hāma- "same, equally, even; together, with" (Mod.Pers./Mid.Pers. ham-; O.Pers./Av. ham-; cf. Skt. sam-; also O.Pers./Av. hama- "one and the same;" Skt. sama-; Gk. homos-; originally identical with PIE numeral *sam- "one," from *som-. The Av. ham- appears in various forms: han- (before gutturals, palatals, dentals) and also hem-, hen-) + *-van- suffix.
2) Taxt "flat;" Mid.Pers. taxtag "tablet, plank, (chess)board."