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

Of a body orbiting another, where the orbiting body takes as long to rotate on its axis as it does to make one orbit. Therefore it always keeps the same hemisphere pointed at the body it is orbiting. Both bodies are tidally locked (→ tidal locking). This phenomenon is a natural consequence of → tidal braking. Synchronous rotation is common throughout the → solar system. It is found among the satellites of → Mars (→ Phobos and → Deimos), → Jupiter (most of Jupiter satellites, including the → Galilean Moons) and → Saturn (e.g. → Iapetus). Similarly, → Pluto and its moon → Charon are locked in mutual synchronous rotation, with both of them keeping the same faces towards each other.

→ synchronous; → rotation.

A type of → accelerator that accelerates charged subatomic particles (generally protons) in a circular path. Unlike → cyclotrons, in which particles follow a spiral path, synchrotrons consist of a single ring-shaped tube through which the particles loop numerous times, guided by precisely synchronized magnetic fields and accelerated at various points in the loop by electric field bursts. See also → synchrotron frequency, → synchrotron radiation.

From synchro- a combining form representing synchronized or synchronous in compound words, from L. synchronus "simultaneous," from Gk. synchronos "happening at the same time," from → syn- "together" + khronos "time" + → -tron.

Sankrotron, from Fr., as above.

The revolution frequency of a → relativistic particle of charge q and mass m in the → uniform magnetic field B of a synchrotron. It is expressed by: f_syn = qB/2πγm, where γ is the → Lorentz factor. This frequency is lower than → cyclotron frequency for a → non-relativistic case.

→ synchrotron; → frequency.

The electromagnetic radiation emitted by high-energy particles that are moving in magnetic fields, as in a synchrotron particle accelerator. The acceleration of the moving charges causes the particles to emit radiation. Radio galaxies and supernova remnants are intense sources of synchrotron radiation. Characteristics of synchrotron radiation are its high degree of polarization and nonthermal spectrum.

→ synchrotron; → radiation.

Of a comet, a curve of points calculated assuming dust grains are emitted continuously at successive instants with a constant value of the radiation pressure to gravitational attraction; also called syndyname. → synchrone.

From → syn- + dyne, → dynamics.

The working together or simultaneous action of separate elements or agencies when the result is greater than the sum of the individual effects or capabilities.

From Mod.L. synergia, from Gk. synergia "joint work, help," from synergos "working together," related to synergein "to work together, help another," from → syn- "together" + → ergon, → work, → erg.

Hamkâruži, from ham- "together," → syn-, + kâruž, → energy, + -i noun suffix.

A hypothesized rapidly spinning doughnut-shaped mass of vaporized and molten rock formed from the collision of two planet-sized objects. In numerical simulations studying giant impacts of rotating objects, a synestia can form if the total → angular momentum is greater than the → co-rotational limit. Beyond the co-rotational limit, the velocity at the equator of a body would exceed the orbital velocity (Simon J. Lock nd Sarah T. Stewart, 2017, arXiv:1705.07858v1).

From → syn- "connected; together" + Hestia the goddess of architecture.

Of or pertaining to the → conjunction of two or more heavenly bodies, especially the interval between two successive conjunctions of a planet or the Moon with the Sun.

From L.L. synodicus, from Gk. synodikos, from synodos "assembly, meeting," from → syn- "together" + hodos "a going, a way."

Hamâgam, literally "coming together," from ham-, → syn- "together," + -â- epenthetic vowel + gam from O.Pers. gam- "to come; to go," Av. gam- "to come; to go," jamaiti "goes," Mod.Pers. âmadan "to come," gâm "step, pace;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE stem *gwem- "to go, come."

The interval of 29.530 588 days (29d 12h 44m 2.80s), on average, between two successive → new Moons. Same as → lunation.

→ synodic; → month.

For planets, the mean interval of time between two successive → conjunctions with or → oppositions to the Sun. For example, → Mars has a synodic period of 779.9 days from Earth; thus Mars' oppositions occur once roughly 2.135 years. In comparison, the synodic period of → Venus is 583.9 days. If the sideral periods of the two bodies around the third are denoted T₁ and T₂, their synodic period is given by: 1/T_syn = |1/T₁ - 1/T₂|.

→ synodic; → period.

Grammar: A word having the same or nearly the same meaning as another in the language. Opposite of → antonym.

From L. synonymum, from Gk. synonymon "word having the same sense as another," from synonymos "having the same name as, synonymous," from → syn- "together, same" + onyma, → name.

Hamcem, from ham-, → syn-, + cem, → meaning.

A brief and condensed summary giving the major points and a general view of a topic.

L.L. synopsis "a synopsis," from Gk. synopsis "general view," from a stem of synoran "to see altogether, all at once," from → syn- "together" + horan "to see, view."

Hanvin, from han- variant of ham-, → syn- + vin variant bin present stem of didan "to see," → phenomenon.

In general, pertaining to or affording an overall view.

M.L. synopticus, from Gk. synoptikos, from synop-, → synopsis, + -tikos.

1) Sun: A map that displays positions of certain events (e.g., → sunspots, → faculae, → filaments, etc.) observed during one solar rotation.
2) Meteorology: The use of data obtained simultaneously over a wide area for the purpose of presenting a comprehensive and nearly instantaneous picture of the state of the atmosphere.

→ synoptic; → map.

The study of the grammatical relationships among signs, independently of their meaning (→ semantics. See also → syntax.

→ syntax; → -ics.

1) Linguistics: The branch of → semiotics dealing with the ways in which words are arranged to show connections within the sentence.
2) Logic: The study of how signs are combined to form constituents regardless of any interpretation or meaning given to them.
3) Informatics: The general set of rules and structural patterns governing the order of words and symbols for issuing commands and writing codes in a programming language.

From Fr. syntaxe, from L.L. syntaxis, from Gk. syntaxis "a putting together or in order, arrangement," from syntassein "to put in order," from → syn- "together" + tassein "to arrange;" PIE base *tāg- "to put in order."

Amrâž, from am-, variant of ham-, → syn-, + râž from Av. rāz- "to direct, put in line, set," rasman- "the lines or files of the army," razan "rule, order;" cf. raj, raž, rak, râk, rezg (Lori), radé, râdé "line, rule, row," rasté, râsté "row, a market with regular ranges of shops;" ris, risé "straight," râst "right, true; just, upright, straight," → system.

The combining of the constituent elements of separate materials or abstract entities into a single or unified entity; opposite of → analysis. → aperture synthesis; → nucleosynthesis.
Chemistry: The forming or building of a more complex substance or compound from elements or simpler compounds.
Philo.: The combination or reconciliation of opposed notions.

From L. synthesis "collection, set," from Gk. synthesis "composition," from syntithenai "put together, combine," from → syn- "together" + tithenai "to put, place," from PIE base *dhe- "to put, to do," cf. Pers. dâdan "to give," as below.

Handâyeš, from han-, variant ham- "together," → syn- + O.Pers./Av. dā- "to give, grant, put," dadāiti "he gives;" Mid.Pers./Mod.Pers. dâdan "to give, put" (cf. Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do") + -y- epenthetic vowel + -eš verbal noun suffix, → synthesize.

To form a material or abstract entity by combining parts or elements; opposite of → analysis.
Chemistry: To combine (constituent elements) into a single or unified entity.

From → synthesis + → -ize.

Handâyidan, verbal form of handâyeš, → synthesis.

A person or thing that synthesizes.

Agent noun from → synthesize.

1) Of, pertaining to, proceeding by, or involving synthesis; opposed to analytic.
2) Noting or pertaining to compounds formed through a chemical process by human agency, as opposed to those of natural origin.

Adj. from synthesize.