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

A mass outflow, consisting of protons, electrons, and other subatomic particles, expelled constantly from the solar corona at about 500 km per second. The solar mass-loss rate in this phenomenon amounts to about 2 x 10^-14 solar masses per year, or about 10⁶ tons per second. → stellar wind.

→ solar; → wind.

The period of time required for the Earth to make one complete revolution around the Sun. Solar year is a general term for: → tropical year, → vernal equinox year, and → autumnal equinox year, which have different lengths.

→ solar; → year.

A member of a very broad class of stars in which is found a mixture of late F, early, middle, and, sometimes, late G type dwarfs and sub-giants. See also → solar analog; → solar twin.

→ solar; → -like; → star.

Any of the various phenomena observable on the Earth that are caused by the influence of the Sun, such as aurora borealis.

→ solar; → terrestrial; → phenomenon.

A criterion for → convective stability in → massive stars. The Solberg-Høiland stability criterion corresponds to the inclusion of the effect of → rotation (variation of → centrifugal force) in the convective stability criterion. It is a combination of → Ledoux's criterion (or possibly → Schwarzschild's criterion) and → Rayleigh's criterion. Both the dynamical shear and Solberg-Høiland instabilities occur in the case of a very large → angular velocity decrease outwards. Therefore, in a → rotating star the Ledoux or Schwarzschild criteria for convective instability should be replaced by the Solberg-Høiland criterion. More specifically, this criterion accounts for the difference of the centrifugal force for an adiabatically displaced fluid element. It is also known as the axisymmetric baroclinic instability. It arises when the net force (gravity + buoyancy + centrifugal force) applied to a fluid parcel in an adiabatical displacement has components only in the direction of the displacement (A. Maeder, Physics, Formation and Evolution of Rotating Stars, 2009, Springer).

E. Høiland, 1939, On the Interpretation and Application of the Circulation Theorems of V. Bjerknes. Archiv for mathematik og naturvidenskab. B. XLII. Nr. 5. Oslo.
H. Solberg, 1936 (reprint), Le mouvement d'inertie de l'atmosphere stable et son rôle dans la théorie des cyclones.
H. Solberg, 1941, On the Stability of the Circular Vortex. Avhandl. utg. av Det Norske Videnskaps-Akademi i Oslo. I. Mat-Naturv. Klasse. No. 11.
Wasiutynski, J. 1946, Astrophysica Norvegica, 4, 1.

The bottom or under surface of the → foot.

M.E., from O.Fr., from L. solea "sandal, bottom of a shoe," from solum "base, bottom, ground," of unknown origin.

From kaf, "the sole of the foot; the palm of the hand," → floor; pâ, → foot.

An optical compensator which produces a constant phase change over the entire field, as opposed to the phase change produced by the → Babinet compensator, which occurs progressively across the field. The compensator consists of two wedges of the same wedge angle and a parallel plate. The optic axes of the two wedges has the same orientation. These form a variable thickness plate. One of the wedges is assembled to the fixed parallel plate. The optic axis of the parallel plate is at 90° to that of the wedges. The other wedge is attached to a micrometer and moves to produce a thickness difference between the fixed and variable thickness plates, thus producing a phase delay.

Jean-Baptiste Soleil (1798-1849); → compensateur.

A long coil of insulated copper wire containing a large number of close turns. The strength of magnetic field produced by a current carrying solenoid is directly proportional to the number of turns in the solenoid and to the strength of current in the solenoid. It also depends on the nature of "core material" used in making the solenoid. The use of → soft iron rod as core in a solenoid produces the strongest magnetism.

From Fr. solénoïde "pipe-shaped," from Gk. solen "pipe, channel" + combining form of eidos "form, shape," → -oid.

Sulvâr, from sul "pipe, gutter," Lori sil, Sangesari sula, Šahmirzâdi solla, Tabari seltek, may be cognate with Gk. solen, as above, + -vâr, → -oid.

1) A body or object having → three  → dimensions (length, breadth, and thickness). Of or pertaining to bodies or figures of three dimensions.
2) One of the four main → states of → matter, in which the substance molecules vibrate about fixed positions. Unlike a gas or liquid, a solid has a fixed shape, and unlike a gas, a solid has a fixed volume.
3) Without holes, free from cavities, not hollow.
4) Dense, thick, or heavy in nature or appearance.
5) Reliable; that can be depended upon.

M.E., from O.Fr. solide "firm, dense, compact," from L. solidus "firm, whole, entire," from PIE base *sol- "whole;" cf. Mod.Pers. har "every, all, each, any;" O.Pers. haruva- "whole, all together;" Av. hauruua- "whole, at all, undamaged;" Skt. sárva- "whole, all, every, undivided;" Gk. holos "whole, complete;" L. salvus "whole, safe, healthy," sollus "whole, entire, unbroken."

Dafzé, from dafzak "big, gross, thick, hard" (Dehxodâ), variant dabz "thick, coarse," → concentrated; cf. Ossetic baezgin "thick, dense;" Shughni divask, Oroshori devaskak "calf of the leg;" Khotanese baysga- "thick, deep, many, large;" Sogd. δβânz "wide, coarse;" Av. bəzuuant- "thick, dense," bazah- "thickness;" Proto-Ir. *(d)banz- "to be(come) thick, dense;" cf. Gk. pakhos "thickness, coarseness;" Latvian biezs "thick" (Cheung 2007).

The figure formed by three or more planes meeting at a common point or formed at the vertex of a cone. The solid angle completely surrounding a point is 4π steradian. → steradian.

→ solid; → angle.

Zâviyé, → angle; fazâyi "of or relating to space," → space; jâmed, → solid.

In electronics, based on or consisting chiefly or exclusively of semiconducting materials, components, and related devices.

→ solid; → state.

The branch of condensed matter physics concerned with the study of rigid matter or solids in terms of their constituent particles (electrons and nuclei). The bulk of solid-state physics theory and research is focused on the electromagnetic, thermodynamic, and structural properties of crystalline solids.

→ solid state; → physics.

1) To become or make solid, hard, or firm.

→ solid; → -fy.

1) To become or make solid, hard, or firm.

→ solid; → -fy.

The state, property, or quality of being solid. Solidness.

→ solid; → -ity.

In the → phase diagram of a → mixture at constant pressure, (such as an → alloy), the → curve that separates the → liquid+solid → phase from the all solid phase. Above the solidus some or all of the mixture will be in a liquid state. See also → liquidus.

From L. solidus, → solid.

Math., Physics: A solution of a certain type of partial differential equation that represents a solitary wave. A soliton is a self-reinforcing wave that maintains its shape while it travels at constant speed. Solitons are caused by a cancellation of nonlinear and dispersive effects in the medium.

From solit(ary) + → -on.

Either of the two points on the → ecliptic at which the apparent → longitude of the → Sun is 90° or 270°. Also the time at which the Sun is at either point. Solstices occur when the Earth's axis is oriented directly toward or away from the Sun, causing the Sun to reach its northernmost and southernmost extremes. → summer solstice, → winter solstice.

M.E., from O.Fr. solstice, from L. solstitium "point at which the sun seems to stand still," from sol, → sun, cognate with Pers. xor, xoršid, hur, as below, + p.p. stem of sistere "to come to a stop, make stand still," akin to Pers. istâdan "to stand," as below.

Xoristân, is composed of two components. The first one xor "sun," variant hur; Mid.Pers. xwar "sun;" Av. hū-, hvar- "sun;" cf. Skt. surya-, Gk. helios, L. sol, cognate with E. sun, as above; PIE base *sawel- "sun." The second component istân "standing," from istâdan "to stand;" Mid.Pers. êstâtan; O.Pers./Av. sta- "to stand, stand still; set;" Av. hištaiti; cf. Skt. sthā- "to stand;" Gk. histemi "put, place, weigh," stasis "a standing still;" L. stare "to stand;" Lith. statau "place;" Goth. standan; PIE base *sta- "to stand."

The great circle of the celestial sphere which passes through the poles of the celestial equator and the solstice points. → equinoctial colure.

Solsticial, adj. of → solstice; → colure.

The two points of the ecliptic the most distant from the equator.

Solsticial, adj. of → solstice; → point.