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

A quasar with detectable radio emission.

→ quasi-; → stellar; → radio; → source.

A form of solid made up of ordered but non-repeating patterns of atoms, a symmetry that is forbidden for periodic crystals. In an ordinary crystal, only 1-, 2-, 3-, 4-, and 6-fold symmetries are possible, since these are the only symmetries that, when combined, can fill space. Prior to the discovery of quasicrystals, it was believed that 5-fold crystal symmetry could never occur. Quasicrystals are remarkable in that some of them display 5-fold or higher-fold forbidden symmetries. They are used as catalysts, in particular at high temperatures, to produce durable kinds of steel, like those used in objects such as razor blades and thin needles made specifically for eye surgery. The Nobel Prize in Chemistry 2011 was awarded to Daniel Schechtman for his discovery of quasicrystals in 1982.

→ quasi-; → crystal.

In a dynamical system, a form of motion that is regular but never exactly repeating. Quasiperiodic motion appears when the system contains two or more incommensurate frequencies.

→ quasi-; → periodic; → motion.

The last two million years of geologic time, comprising the Pleistocene and Holocene glacial epochs. Estimates of the date of the beginning of the Quaternary vary between 2.5 and 1.6 million years ago.

Quaternary, from L. quaternarius "consisting of four," from quatern(i) "fourt at a time" + -arius "-ary;" → period.

Dowrân, → period; cahârom "fourth," from cahâr "four" + -om "-th."

1a) To put out or extinguish.
1b) Electronics: To terminate the discharge in a vacuum tube by application of a voltage.
2) To become extinguished.
3) To dip a heated object into a liquid to quickly reduce the temperature.

M.E. quenchen, from O.E. acwencan "to quench," form of root of cwincan "to go out, be extinguished."

Oseridan, oserândan, from Yaghnobi oser- "to cool," Wakhi wəsər-/wəsərt "to fade, wither," related to Pers. sard "cold, cool" (Kurd. sar, Baluchi sârt, Ossetian sald "cold" ), afsordan, afsârdan "to congeal;" Mid.Pers. sard/sart "cold;" Av. sarəta- "cold;" cf. Skt. śiśira- "cold;" L. calidus "warm;" Lith. šaltas "cold;" Welsh clyd "warm;" PIE *keltos- "cool."

The frequency at which an oscillation is intermittently quenched, as in a super-regenerative receiver.

→ quench; → frequency.

A galaxy in which star formation is turned off or suppressed by some physical processes. → star formation quenching.

→ quench; → quenching; → galaxy.

1) The process of extinguishing, removing, or diminishing a physical property.
2) In the dealing with star formation in galaxies, the term quenching has been used with two different meanings. Either to indicate the termination of the star formation activity, or the process of maintaining a galaxy quiescent over its lifetime, despite the fresh fuel produced by stellar evolution and gas inflows. Given the substantially different timescales involved in the two processes, it remains debated whether one single mechanism is responsible for both the onset and the maintenance of quenching (Man and Belli, 2018, arXiv:1809.00722).

Verbal noun, → quench + → -ing.

A period during which an eruptive astronomical phenomenon is in a state of inactivity.

→ quiescent; → -ence.

Being at rest; quiet; still; inactive. → quiescent prominence.

From L. quiescens, pr.p. of quiescere, from quies "rest, quiet."

Âramidé "quiescent, reposed, rested," from âramidan "to rest, repose," related to ârâm "quiet" (Mid.Pers. râm "peace," râmenidan "to give peace, pleasure," râmišn "peace, pleasure" (Mod.Pers. râmiš), Av. ram- "to stay, rest;" cf. Skt. ram- "to stop, stand still, rest, become appeased;" Gk. erema "quietly, gently;" Goth. rimis "rest;" Lith. rãmas "rest").

A → solar prominence of relatively cool material that hovers over Sun's surface for weeks or months with relatively little overall change. Such prominences are suspended above the → chromosphere by → magnetic fields. A quiescent prominence may suddenly erupt outward and dissipate, often to be replaced, in the same location, by a new one. See also → eruptive prominence; → loop prominence.

→ quiescent; → prominence.

The Sun when the 11-year cycle of → solar activity is at a minimum.

Quiet, M.E., from from O.Fr. quiete, from L. quies (genitive quietis) "rest, quiet;" → Sun.

Xoršid, → Sun; ârâm "quiet, rest, tranquility," → rest.

In cosmology, a hypothetical new "element," distinct from any normalmatter (either → baryonic or not) or radiation, intended to explain the observed ever → accelerating expansion of the Universe. Quintessence can have several types and differs from the → cosmological constant in that it can vary in space and time. In modern physics, the four known "elements" are the → baryons (proton, neutron, etc.), the → leptons (neutrinos, electrons, etc.), the → photon, and the hypothetical → non-baryonic matter, which is thought to be 80% of the total matter in the Universe. The quintessence field is a possibility which can be confirmed or disproved by measurements of the → dark energy value at different → redshifts. In some models, the quintessence is fine-tuned to explain both the → cosmological constant problem and the → inflation in the very → early Universe.

Literally "fifth essence," from M.Fr. quinte essence, from M.L. quinta essentia, from L. quinta, fem. of quintus "fifth," from quinque "five," cognate with Pers. panj, → five + essentia "being, essence," from esse "being; → existence" + -entia "-ence." In Aristotelianism, the fifth element, distinguished from the four earthly elements, was the substance of celestial bodies. Subsequently, quintessence became the purest, most highly concentrated form of a nature or essence.

Panjomin gowhar "fifth essence," from panjomin "fifth," from panj, → five, cognate with L. quinque, + gowhar "essence, substance; jewel, pearl, gem," Mid.Pers. gohr "essence, substance; jewel; stock, lineage;" cf. Skt. gôtra- "family, race, lineage, origin."

Any group of five things or persons. → Stephan's Quintet.

From Fr. quintette, from It. quintetto, diminutive of quinto "fifth," from L. quintus, related to quinque "five" cognate with Pers. panj→ five.

Panjtâyé, from panj, → five, + tâ "fold, plait, ply, part;" Mid.Pers. tâg "piece, part" + -(y)é nuance suffix.

Math.: Of the fifth degree; a quantity of the fifth degree.

From L. quint(us) "fifth," → five, + → -ic;

Panjomik, from panjom "fifth," from panj "five" + -om "-th" + -ik, → -ic.

An equation containing unknowns of the fifth power.

→ quintic; → equation.

A polynomial of degree five.

→ quintic; → polynomial.

A bright → open cluster of stars located within 100 light-years of the center of the Milky Way Galaxy, and one of the three → Galactic center clusters. The Quintuplet cluster was originally noted for its five very bright stars, but it is now known to contain many luminous → massive stars that are not detected at visible wavelengths due to heavy extinction by dust along the line of sight. The cluster is about 4 million years old and had an initial mass over 10⁴ solar masses. The five brighter stars of the cluster are dusty → WC Wolf-Rayet stars. The Quintuplet cluster also contains two → Luminous Blue Variables, the Pistol star and FMM362. The Pistol star has a luminosity 10⁷ times solar making it one of the most luminous stars known. The Quintuplet cluster is more dispersed than the nearby → Arches cluster.

Quintuplet, from the five brightest stars originally observed; → cluster.

1) General: A proportional part or share of a fixed total amount or quantity.
2) Computers: The amount of a resource (disk, memory, CPU time, etc.) that is allocated to a user.

From L. quota pars "how big a share?," from quotus "of what number."

Bahrâl, from bahr "part, portion, share, lot," → quotient + -âl, → -al.

The number resulting from the division of one number by another. Also the fractional notation that indicates this number.

From L. quotiens "how many times," from quot "how many," related to quis "who."

Bahr "part, portion, share, lot," related to baxš "portion, part, division," baxšidan "to divide, distribute, grant" (Mid.Pers. baxt "fortune, fate," baxtan, baxšidan "to distribute, divide;" Av. base bag- "to attribute, allot, distribute," baxš- "to apportion, divide, give to," baxta- "what is allotted (luck, fortune)," baxədra- "part, portion," baγa- "master, god;" O.Pers. bâji- "tribute, tax;" cf. Skt. bhaj- "to share, divide, distribute, apportion," bhájati "divides," bhakta- "allotted; occupied with; a share; food or a meal, time of eating?" pitu-bháj- "enjoying food;" Gk. phagein "to eat (to have a share of food)"; PIE base *bhag- "to share out, apportion").