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

The area over which the → meteorite fragments from a particular → fall are dispersed.

Strewn, p.p. of strew, from M.E. strewen, O.E. strewian; cf. O.S. stroian, O.N. stra, Dan. strø, Swed. strö, M.Du. strowen, Du. strooien, O.H.G. strouwen, Ger. streuen, Goth. straujan "to sprinkle, strew;" PIE base *stere- "to spread, extend, stretch out;" from which Pers. gostar-, gostardan "to stretch, expand;" Av. star- "to spead out;" → field.

Meydân, → field; paxš "scattered," → diffuse.

Secondary synchrones that originate at a certain point in some comets' dust tail, a point where for some reason the dust particles have fragmented.

Mod.L. stria "strip, streak," L. "furrow, channel;" cognate with Du. striem, O.H.G. strimo, Ger. Strieme "stripe, streak," from PIE base *streig- "to stroke, rub, press."

Xaš "streak," dialectal Qomi xaš "streak, stria, mark," Yaqnavi xaš "to draw," Lori kerr "line;" litterary Pers. xatt→ line; Mid/Mod.Pers. kešidan, kašidan "to draw, protract, trail, drag, carry;" Av. karš- "to draw; to plow," karša- "furrow;" Proto-Iranian *kerš-/*xrah- "to draw, plow;" cf. Skt. kars-, kársati "to pull, drag, plow;" Gk. pelo, pelomai "to move, to bustle;" PIE base k^wels- "to plow."

1) General: A thin cord, usually made of twisted fibers, used for fastening, hanging, or tying. Something that resembles string in form or texture.
2) Music: A cord stretched across a musical instrument and vibrated to produce sound.
3) Subatomic string; → string theory.
4) → cosmic string.

M.E. string, streng; O.E. streng "line, cord, thread;" Du. streng,Ger. Strang "rope, cord;" PIE base *strenk- "stiff, tight."

Târ "thread, warp, string" (related to tur "net, fishing net, snare," tâl "thread" (Borujerdi dialect), tân "thread, warp of a web," from tanidan, tan- "to spin, twist, weave;" Mid.Pers. tanitan; Av. tan- to stretch, extend;" cf. Skt. tan- to stretch, extend;" tanoti "stretches," tántra- "warp; essence, main point;" Gk. teinein "to stretch, pull tight;" L. tendere "to stretch;" Lith. tiñklas "net, fishing net, snare," Latv. tikls "net;" PIE base *ten- "to stretch").
Rismân "thread, string, cord" variants rasan, ras, ris, razé, rajé, rijé, rešmé, Mid.Pers. rasan, cf. Skt. rajju- "rope, cord," L. restis "cord," Lith. resgis, rekstis "wicker basket," O.L.G. risch; PIE base *rezg- "to plait."

The latest theory of fundamental physics in which the basic entity is a one-dimensional → brane rather than the "zero-dimensional" point of conventional elementary particle physics. The one-dimensional string-like objects exist in the normal four dimensions of → space-time plus additional dimensions, the total dimensions being ten, eleven, or twenty-six depending on the version of the theory. Particles are strings that vibrate in different ways to account for their various properties.

→ string; → theory.

1) A long, flat, narrow piece of something. → instability strip.
2a) To deprive of covering; to deprive of clothing; make bare or naked. → ram pressure stripping.
2b) To take off clothes.

1) M.E. probably from M.L.G. strippe "strap, thong," related to stripe.
2) M.E. strippe, O.E. *stryppan; cf. M.Du. stropen "to strip off, to ramble about plundering," O.H.G. stroufen "to strip off, plunder," Ger. streifen "strip off, to ramble, roam, rove."

1) Navâr "strip."
2) Loxtândan, acusative of loxtidan, loxt kardan "to strip, to deprive of," infinitive of loxt "naked, deprived of," variants rut, lut, rud "plucked, stripped of its feathers (a bird) or of its wool (a lamb);" cf. Kurd. we-rutin "to pluck, strop off;" Proto-Ir. *rauH "to pluck, pull out;" IE cognates Lith. liautis "to be cut off, mutilated;" O.H.G. lô, E. lye (Cheung 2007).

A theoretical sphere of → ionized hydrogen created by energetic → ultraviolet→ photons of a hot, → massive star embedded in a uniform interstellar → molecular cloud and lying at the center of the sphere. → H II region.

Named after Bengt Strömgren (1908-1987), a Danish astrophysicist, who put forward the first and simplest version of the model in 1939; → sphere.

A → photometric system, also called the → uvby system.

→ Stromgren sphere; → system.

Having an intense, powerful, or vivid effect.
→ strong anthropic principle, → strong arm spiral galaxy, → strong encounter, → strong force, → strong gravitational lensing, → strong interaction, → strong lensing.

O.E. strang "physically powerful, powerful in effect, forceful;" cf. O.N. strangr "strong," Du. streng "strict, rigorous," O.H.G. strang "strong, bold, hard," Ger. streng "strict, rigorous."

Sotorg "large, strong," Mid.Pers. sturg "fierce; gross, coarse," Av. stūra- "strong, large, rough," stāuuišta- "strongest, biggest," cf. Skt. sthūrá- "strong, big, massy, thick," Gk. stylos "column, pillar," M.L.G. stūr "big, strong, coarse."
Zurmand, from zur, → strength, + -mand possession suffix.
Nirumand, from niru, → force + -mand possession suffix.

A version of the → anthropic principle that claims that the → Universe must be suitable for the formation of → intelligent life at some point. Compared with the → weak anthropic principle, this version is very controversial. Its implications are highly speculative from a scientific viewpoint.

→ strong; → anthropic; → principle.

A galaxy with prominent stellar → spiral arms and little star formation between stellar arms, such as M51.

→ strong; → arm; → spiral; → galaxy.

In a star cluster, a → close encounter that strongly changes a star's velocity.

→ strong; → encounter.

The force responsible for holding quarks and gluons together to form protons, neutrons and other particles. It is the strongest of the four fundamental forces. Same as → strong interaction.

→ strong; → force.

A → gravitational lensing phenomenon in which the image distortion is strong enough to be readily recognized, such as in the case of the → Einstein cross or when giant luminous arcs show up in → galaxy clusters (e.g. Abell 2218). Opposite to → weak gravitational lensing.

→ strong; → gravitational; → lensing.

The interaction between quarks that is transmitted by gluons. The characteristic range of the strong interaction is 10^-13 cm, and the time scale over which it operates is on the order of 10^-23 second. Also called → strong force.

→ strong; → interaction.

A situation where the mass concentration in the central regions of → galaxy clusters exceeds the → critical density required for lensing, resulting in multiple images of background objects.

→ strong; → lensing.

A metallic chemical element; symbol Sr. Atomic number 38; atomic weight 87.62; melting point 769°C; boiling point 1,384°C; specific gravity 2.6 at 20°C. Strontium is a soft, silver-yellow metal with three allotropic crystalline forms. It is found in nature only in the combined state, as in strontianite. It is used in fireworks, flares, and tracer bullets. The radioactive isotope Strontium-87, the daughter of Rubidium-87, has a half-life of 48.8 x 10⁹ years.

The name derives from Strontian "a town in Scotland." The mineral strontianite is found in mines in Strontian. The element was discovered by the Scottish chemist and physician Thomas Charles Hope in 1792 observing the brilliant red flame color of strontium. It was first isolated by the English chemist Humphry Davy in 1808.

The arrangement of parts in an object or organism.

M.E., from L. structura "a fitting together, adjustment, building," from structus, p.p. of struere "to pile, build, assemble," related to strues "heap," from PIE *stere- "to spread, extend, stretch out;" cf. Pers. gostar-, gostardan "to spread;" Av. star- "to spread," starati "spreads;" Skt. star- "to spread out, extend, strew," strnati "spreads;" Gk. stornumi "I spread out," strotos "spread, laid out;" Ger. Strahlung "radiation," from strahlen "to radiate," from Strahl "ray;" from M.H.G. strāle; from O.H.G. strāla "arrow, stripe."

Sâxtâr, from sâxt "made; make, construction, structure; style," past stem of sâxtan, sâzidan "to build, make, fashion; to adapt, adjust, be fit" (Mid.Pers. sâxtan, sâz-, Manichean Parthian s'c'dn "to prepare, to form;" Av. sak- "to understand, to mark," sâcaya- (causative) "to teach") + -âr verbal noun suffix.

The study of the processes that gave rise to the apparition of matter concentrations, such as → superclusters of galaxies, → galaxy clusters, and galaxies, in a homogeneous → expanding Universe. Cosmic structures are believed to result from → density fluctuations that existed in the → early Universe before radiation and matter decoupled (→ decoupling era or → recombination era). Initial → quantum fluctuations in the → inflaton field were expanded by → inflation. Inflation amplified them up to scales that correspond to those of galaxy clusters and beyond. Generally, a model of structure formation includes three main ingredients: 1) background cosmology, 2) model for fluctuation generation, and 3) types of → dark matter.
See also:
→ bottom-up structure formation, → hierarchical structure formation, → Silk damping, → top-down structure formation.

→ structure; → formation.

1a) Application of the mind to the acquisition of knowledge, as by reading, investigation, or reflection.
1b) The cultivation of a particular branch of learning, science, or art.
1c) Something studied or to be studied.
1d) Research or a detailed examination and analysis of a subject, phenomenon, etc. A written account of such research, examination, or analysis.
2a) To apply oneself to the acquisition of knowledge, as by reading, investigation, or practice.
2b) To think deeply, reflect, or consider.
2c) To take a course of study, as at a college (Dictionary.com).

M.E. studie, from O.Fr. estudie "care, skill, thought; study, school," from L. studium "study, application;" originally "eagerness," from studere "to press forward, be eager for, pursue," from PIE *(s)teu- "to push, stick, beat;" cf. Gk. typtein "to strike," typos "a blow, mold;" Skt. tup- "harm," tundate "pushes, stabs;" Gothic stautan "push."

Parhâné, from Proto-Ir. *pari-huan- "to read thoroughly, to read through," from *pari- "through, throughout; thoroughly" (O.Pers. pariy "around, about;" Av. pairi "around, over") + *huanH- "to call;" cf. Pers. xândan, x^vandan "to read, to sing" (Av. x^van- "to sound;" Skt. svana- "sound," svan- "to sound," svanati "it sounds;" O.E. swinn "music, song"); cf. Kurd. xwendin "to study, read;" Lori hané "to read;" Karingâni hoyniyan, Baluci vonag, Awromâni wânây "to read;" Khotanese hâvn- "to speak."

The fifth confirmed → satellite of → Pluto discovered in 2012 using a set of the → Hubble Space Telescope. Also called Pluto V (P5). It orbits Pluto between → Charon and → Nix at a distance of about 42,000 km. Styx is estimated to have a diameter of between 10 and 30 km, and an → orbital period of 20.2 days.

Named for the Greek mythological river that separates the world of the living from the realm of the dead.