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

An astronomical association of astronomers that is the controlling body of world astronomy. It was founded in Brussels in 1919.

→ international; → astronomical; → union.

A weighted average of the time kept by about 200 caesium atomic clocks in over 50 national laboratories worldwide. It has been available since 1955, and became the international standard on which UTC is based on January 1972.

→ international; → atomic; → time.

An imaginary line following approximately the 180th meridian which, by international agreement in 1884, marks the beginning or or end of a day. The regions to the east of which are counted as being one day earlier in their calendar dates than the regions to the west.

→ international; → date; → line.

The metric system of units based on the → meter, → kilogram, → second, → ampere, → kelvin, and → candela. Also called MSKA system. Other SI units are → hertz, → radian, → newton, → joule, → watt, → coulomb, → volt, → ohm, → farad, → weber, and → tesla.

→ international; → system; → unit.

A satellite dedicated to spectroscopic observations of astronomical objects in ultraviolet wavelengths, launched in 1978. It was an international collaboration between → NASA, the → European Space Agency (ESA), and the United Kingdom's Science and Engineering Research Council. It operated until September 1996 and collected over 70,000 spectra. IUE consisted of a 45-cm telescope (f/15) equipped with two spectrographs operating in the ranges 1850-3300 Å and 1150-2000 Å. Each spectrograph had a high-resolution and a low-resolution mode with resolutions of about 0.2 Å and 6 Å respectively.

→ international; → ultraviolet; → explorer.

An international cooperation whose objective is to facilitate the international coordination and collaboration necessary for the development and deployment of the tools, systems and organizational structures necessary to enable the international utilization of astronomical archives as an integrated and interoperating → Virtual Observatory. The IVOA, created in 2002, now comprises 20 Virtual Observatory programs from various countries and international organizations.

→ international; → virtual; → observatory; → alliance.

An → interplanetary manifestation of a → coronal mass ejection.

→ interplanetary; → coronal; → mass; → ejection.

In a series of numerical values, the operation performed to find a number or value which is not present but which can be derived approximately from those that are present.

Verbal noun of interpolate, from L. interpolatus, p.p. of interpolare "to make new, refurbish, alter," from → inter- + polare, related to polire "to smoothe, polish."

Andaryâbeš, from andar-, → inter-, + yâbeš "finding," verbal noun of yâftan, yâbidan "to find, discover; to obtain, acquire;" Mid.Pers. ayâftan, ayâpênitan "to reach, attain;" Manichean Mid.Pers. 'y'b "to attain;" Parthian, Sogdian (+ *pati-) pty'b "to reach, obtain;" Av. ap- "to reach, overtake," apayeiti "achieved, reached;" Skt. âp- "to reach, gain," âpnoti "reaches, gains;" Gk. hapto, haptomai "to touch, cling to, adhere to;" L. apiscor "touch, reach;" PIE base *ap- "to take, reach."

1) The act of interpreting; elucidation; explication.
2) Physics: Providing relations between the mathematical symbols of a → formalism and physical → observables. → Copenhagen Interpretation.

Verbal noun of → interpret.

The action of interrupting or being interrupted.

Verbal noun from → interrupt.

The act, process, or result of intersecting.
Math.: A set of elements common to sets A and B, denoted by A ∩ B. → section.

Verbal noun of → intersect.

The absorption of light from stars and other objects by intervening gas and dust in interstellar space.

→ interstellar; → absorption.

The dimming of light traveling in the interstellar space due to the combined effects of absorption and scattering by interstellar dust particles. Interstellar extinction increases at shorter (bluer) wavelengths, resulting in → interstellar reddening.

→ interstellar; → extinction.

The polarization of starlight caused by aligned → interstellar grains, so that initially → unpolarized light from a star is partially polarized by the time it reaches the Earth.

→ interstellar; → polarization.

A global ionizing radiation in the → interstellar medium provided by various sources all together.

→ interstellar; → radiation; → field.

An apparent twinkling of the signals from distant point-like radio sources (pulsars). It is due to turbulence, i.e. fluctuations in the electron density of the interstellar ionized gas, through which the signals have passed on their way to Earth.

→ interstellar; → scintillation.

The act or fact of intervening.

M.E., from M.Fr. intervention, or directly from L.L., from L. intervenire "to come between, interrupt," from → inter-, + venire "to come," as below.

Andargam "coming between," from andar- "between," → inter-, + gam "to come;" cf. Av./O.Pers. gam- "to come; to go," Mod./Mid.Pers. gâm "step, pace," âmadan "to come;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" O.H.G. queman "to come;" E. come; PIE root *g^wem- "to go, come."

A pure semiconductor containing no → impurity atoms. → extrinsic semiconductor.

→ intrinsic; → semiconductor.

1) The act or process of introducing; the state of being introduced.
2) A part of a book or treatise preliminary to the main portion; a preliminary treatise or course of study (Merriam-Webster.com).

Verbal noun of → introduce; → -tion.

The immediate apprehension of knowledge through the use of the senses, without conscious reasoning or analysis. → intuitive, → intuitionism.

M.E., from L.L. intuitionem "a looking at, consideration," noun of action from p.p. stem of intueri "look at, consider," from → in- "at, on" + tueri "to look at, watch over."

Dargas, literally "looking at, consider," from dar-, → in-, + *gas "to look, appear;" cf. Parthian âgas "visible, apparent," pargas- "to observe, take care," related to negâh "look, attention," âgâh "aware, knowing;" Sogd. pcks- "to expect;" Proto-Ir. *kas- "to look, appear" (Cheung 2007).