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

The passage of an → exoplanet across the face its star.

→ exoplanetary; → transit.

The part of → astrophysics that searches and studies → extrasolar planets.

→ exoplanet; → -logy.

1) The outermost portion of the Earth's → atmosphere. Extremely tenuous, it lies above the → ionosphere from a height of about 500 km, to the edge of → interplanetary space.
2) An extremely tenuous kind of atmosphere surrounding a → solar system body. Since the → mean free path is much greater than the atmospheric scale height. The → atoms or → molecules never collide with each other. → lunar exosphere.

→ exo- + → sphere.

Relating to or describing any process in which a system releases heat to its surrounding environment.

From → exo- + -therm, from Gk. therme "heat," from PIE *ghwerm-/*ghworm- "warm;" cf. Pers. garm "warm;" L. fornax "an oven;" O.E. wearm "warm" + → -ic.

From garmâ "heat, warmth" (Mid.Pers. garm; O.Pers./Av. garəma- "hot, warm;" cf. Skt. gharmah "heat;" Gk. thermos "warm;" L. formus "warm;" P.Gmc. *warmaz; O.E. wearm; O.H.G., Ger. warm; PIE *ghworm-/*ghwerm-, as above) + zâ verbal adj. and agent noun of zâdan "to bring foth, give birth," (Mid.Pers. zâtan; Av. zan- "to bear, give birth to a child, be born," infinitive zazâite, zâta- "born;" cf. Skt. janati "begets, bears;" L. gignere "to beget;" PIE base *gen- "to give birth, beget").

1) Of foreign origin or character; not native; introduced from abroad, but not fully naturalized or acclimatized.
2) Strikingly unusual or strange in effect or appearance.
3) Of a uniquely new or experimental nature (Dictionary.com).
See: → exotic star.

M.E., from M.Fr. exotique and directly from L. exoticus, from Gk. exotikos "foreign," literally "from the outside," from → exo- "outside."

Osgânik, from os-, → ex-, + gân relation suffix, from Mid.Pers. -gânag, -gâna, + -ik, → -ic.

A hypothetical → compact object composed of particles other than electrons, protons, and neutrons balanced against → gravitational collapse by → degeneracy pressure of corresponding quantum properties.

→ exotic; → star.

1a) To change (something) from a smaller form and/or size to a larger one.
1b) To increase the extent, number, volume or scope of (something).
1c) To express (something) at length and/or in detail.
1d) Math.: To write (a mathematical expression) as a sum of terms in an extended form.
2) to increase or grow in extent, bulk, scope; to spread out; unfold; develop.
See also → spread, → extend, → dilate.

M.E. expanden, from O.Fr. espandre "to spread, spread out," from L. expandere "to spread out, unfold, expand," from → ex- "out" + pandere "to spread, stretch," from nasalized form of PIE root *pete- "to spread," a Pers. offshoot of which is pahn "wide, broad," as below. from

Sopândan, "to stretch, to extend, open out" from so- "out," → ex-, + pân, from pan, variant of pahn "wide, large, broad, ample, extensive," from Mid.Pers. pah(a)n; Av. paθana- "broad, wide, spacious;" PIE root *pete- "to spread;" cf. L. patere "to be open," Gk. petannynai "to spread out," petalon "a leaf."
Alternatively, sopândan "to open up, to open out," from so- "out," → ex-, + pân "open," cf. Yaghnobi pen, peyn "to open, unroll," Sogd. pyn- "to open," ultimately from Proto-Ir. *apa- "off, away, from" + *hHai- "to chain, bind," from which Pers. gošâdan "to open, release" (Cheung 2007).

A → radio interferometer array consisting of 27 25-meter diameter antennas located on the Plains of San Agustin in West-Central New Mexico. EVLA will operate at any frequency between 1.0 and 50 GHz and will have a continuum sensitivity improvement over the → VLA by factors of 5 to 20.The EVLA project is expected to be completed in 2012. See also the EVLA homepage.

→ expand; → very; → large; → array.

The deduction based on the observational fact that the greater the → distance to a → galaxy, the greater the → redshift in its → spectral lines (→ Doppler effect). The observations strongly indicate that galaxies appear to be moving away from us with speeds proportional to their distance. This is in agreement with the overall → expansion of the → Universe.

→ expand; → -ing; → Universe.

1) General: The act or process of expanding; the state or quality of being expanded. → expansion of the Universe.
2) Math.: The process of expressing a quantity, or a quantity expressed, as a sum of a series of terms. For example the expression (2x - 1)(x + 3) can be expanded to: 2x² + 5x - 3. See also → binomial expansion.

Noun from → expand.

The receding of galaxies from one another at a speed proportional to their separation, as inferred by Edwin Hubble from the observed Doppler shift of distant galaxies. → Hubble constant describes the local rate of the expansion.

→ expansion; → universe.

A → scale factor that relates the size of the Universe R = R(t) at time t to the size of the Universe R₀ = R(t₀) at time t₀ by R = aR₀. The expansion parameter represents the history of expansion of the Universe.

→ expansion; → parameter.

Statistics: Same as → mathematical expectation, → expected value.

From L. expectare "to await, hope," from → ex- "thoroughly" + spectare "to look," from → specere "to look at," → -scope.

Bayusesš, verbal noun of bayusidan "to expect;" Mid.Pers. pyws- "to hope for, desire" (prefixed *pati-); O.Pers. vasiy "at will, greatly, utterly," vašna- "will, favor;" Av. vas- "to will, desire, wish, long for," vasəmi "I wish," vasna- "will, favor," ušti- "desire, wish, will," vasô, vasə "at one's will." This word is extant in several Mod.Pers. dialects, Tabari vessen "to wish, desire," Gilaki vâssan "to wish, desire," vâsti "desire," Kurd. wistin "to desire, wish," Lâri avessa "to desire," colloquial Tehrâni vâsé "for" (Mid.Pers. vasnâd "because"); cf. Skt. vaś- "to wish, want, desire," váśa- "wish, desire," vasēna "for, because;" Gk. ekon "voluntary;" PIE base *uek- "to wish."

Statistics: Same as → mathematical expectation, → expectation.

→ expectation; → value.

To use up. See also → spend, → consume.

From L. expendere "to pay out, weigh out money," from → ex- "out" + pendere "to pay, weigh."

Hazinidan, back formation from haziné, → expenditure.

1) The act of expending something, especially funds; disbursement; consumption.
2) Something that is expended; expense (Dictionary.com).

From → expend.

Mid.Pers. uzên, uzênag "expense;" ultimately from Proto-Ir. *uz-ayana- literally "going out" (cf. Awromani ziāy-/-zia- "to go out"), from uz-, → ex-, + *Hai- "to go," → efficiency.

An act or operation for the purpose of discovering something unknown or of testing a principle, supposition. See: → Aspect experiment, → Carnal-Mlynek experiment, → Davisson-Germer experiment, → double-slit experiment, → Eratosthenes experiment, → Hafele-Keating experiment, → Hertz experiment, → Michelson-Morley experiment, → Millikan's oil-drop experiment, → Pascal's barrel experiment, → random experiment, → Stern-Gerlach experiment, → thought experiment, → toothed-wheel experiment, → Trouton-Noble experiment, → Young's experiment.

From O.Fr. experiment, from L. experimentum "a trial, test," from experiri "to test, try," from → ex- "out of" + peritus "experienced, tested."

Âzmâyeš, verbal noun of âzmudan, âzmây- "to try, experiment, test;" Mid.Pers. uzmudan, ôzmutan "to test, try, prove;" from O.Pers./Av. *uz-māy-, from uz-, → ex- + mā(y)- "to measure," Proto-Ir. *maH- "to measure;" PIE *meH- "to measure;" cf. Skt. mati "measures," matra "measure;" Gk. metra "lot, portion;" L. metri "to measure."

1) To make plain or clear; to render understandable or intelligible.
2) To make clear the cause or reason of; to account for.
3) To assign a meaning to; → interpret.

From L. explanare "to make level, smooth out; make clear," from → ex- "out" + planus "flat; clear."

Ostâhidan, literally "to unfold, spread out" (on the model of Fr. expliquer, Sp. explicar, from L. → ex- "out" + plicare "to lay, fold, twist," from PIE base *plek- "to plait, twist;" cf. Gk. plekein "to plait," L. plectere "to plait, braid, intertwine," O.C.S. plesti "to braid, plait, twist," Goth. flahta "braid"), from os- "out," → ex- + tâh "fold, plait, ply;" Mid.Pers. tâg "piece, part" + -idan infinitive suffix.

1) The act or process of explaining.
2) A statement made to clarify something and make it understandable.

Verbal noun of → explain.

1) General: Precisely and clearly expressed.
2) Math.: → explicit function.

From Fr. explicite, from L. explicitus "unobstructed," variant p.p. of explicare "unfold, unravel, explain," → explain.

Ostâhi, from ostâh present stem of ostâhidan, → explain, + -i adj. suffix.