An Etymological Dictionary of Astronomy and Astrophysics
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The energy emitted from unit surface area of body per second.

→ emissive; → power.

The ratio of energy radiated by a material to energy radiated by a black body at the same temperature.

→ emissive + → -ity.

A → forbidden line in → emission.

→ forbidden; → emission; → line.

The radiation emitted when a → free electron is captured by an → ion. See also: → free-free emission; → bound-free transition.

→ free; → bound; → emission.

→ Electromagnetic radiation produced in a → plasma by → free electrons scattering off → ions without being captured. The electrons are free before the interaction and remain free afterward.

→ free; → emission.

The emission of radiation from an atom when it is bombarded by photons. The induced radiation has the same wavelength and direction as the bombarding radiation. Same as → stimulated emission.

→ induced; → emission.

The portion of → electromagnetic radiation from → astrophysical objects in → infrared frequencies.

→ infrared; → emission.

A NASA lander designed to study the interior of the planet Mars. It will be a stationary mission, in contrast to NASA's famous Opportunity, Spirit and Curiosity rovers. Staying in place is necessary for its major science goals, which include learning more about the Martian composition, and how tectonically active the red planet is. InSight launched toward Mars on May 5, 2018, landed on Nov. 26, 2018, at the Martian Elysium Planitia, an equatorial zone just south of an ancient volcanic area. InSight will send back data about Mars' interior for about 1 Mars year, or 728 Earth-days. The lander uses sophisticated instruments, to delve deep beneath the surface and seek the fingerprints of the processes that formed the terrestrial planets. It does so by carrying out → seismology, heat flow measurements, and precision tracking.

InSight, short for Interior Exploration using Seismic Investigations, Geodesy and Heat Transport; → mission.

A follow-up mission of the → Kepler satellite funded by → NASA. K2 provides an opportunity to continue Kepler's observations in the field of → exoplanets and expand its role into new astrophysical observations by assigning to Kepler new mission.

K, short for → Kepler spacecraft; 2, for second → mission.

Same as → LINER.

→ low; → ionization; → nuclear; → emission; → line; → region.

An emission arising from the → maser process.

→ maser; → emission.

1) Fail to hit, reach, or come into contact with (something aimed at); to fail to do something.
2) Pass by without touching.
3) Feel or notice the loss or absence of.

M.E. missen, O.E. missan "fail to hit, miss (a mark); fail in what was aimed at," akin to Du. missen, Ger. missen "to miss, fail," from PIE *mei- "to change, go, move."

Napidan, literally "fail attain, reach, or find," from negation suffix na-, → not, + Av. ap- "to reach, attain;" cf. Mid./Mod.Pers. (+abi-) yâftan "to obtain, to find;" Proto-Ir. *Hap/f- "to reach, attain;" PIE *H₁ep- "to take, seize, grab;" cf. L. apiscor "to reach, to get" (Cheung 2007).

An object or weapon for throwing, hurling, or shooting. → ballistic missile.

From Fr. missile, from L. missile "weapon that can be thrown," from missus, p.p. of mittere "to send."

Mušak, literally "little mouse," or "mouse like," from a firework explosive that was likened to a mouse, from muš, → mouse, + -ak diminutive or similarity suffix.

The unseen mass whose gravitational influence is needed to account for the way galaxies rotate, and also to bind clusters of galaxies together. It is thought to consist, in part, of giant halos of dark matter that surround the visible portions of galaxies, and similar material that invisibly occupies the intergalactic voids. Same as → hidden mass; → dark matter.

Missing, from miss "to fail to be present," from M.E. missen, O.E. missan; cf. O.Fris. missa, M.Du. missen, Ger. missen "to miss, fail;" → mass.

Jerm, → mass; gomšodé "lost, missing," from gom "missing, lost" + šodé p.p. of šodan "to become" (from Mid.Pers. šudan, šaw- "to go;" Av. šiyav-, š(ii)auu- "to move, go," šiyavati "goes," šyaoθna- "activity; action; doing, working;" O.Pers. šiyav- "to go forth, set," ašiyavam "I set forth;" cf. Skt. cyu- "to move to and fro, shake about; to stir," cyávate "stirs himself, goes;" Gk. kinein "to move;" Goth. haitan "call, be called;" O.E. hatan "command, call;" PIE base *kei- "to move to and fro"); napide, p.p. of napidan, → miss.

The observed underabundance, by one or two orders of magnitude, of → dwarf galaxies orbiting → spiral galaxies compared to their number predicted by the standard model. The → cold dark matter (CDM) model predicts that dwarf galaxies are the building blocks of large galaxies like the Milky Way and should largely outnumber them. Dwarf galaxies form first, they merge into bigger and bigger galaxies, and galaxies into groups of galaxies. The dark matter halos, however, are very dense, and dwarf halos are not destroyed in the merging, resulting in their large predicted number, in numerical simulations.

Probably first dealt with in an article entitled "Where Are the Missing Galactic Satellites?" (Lypin et al. 1999, ApJ 522, 82); → missing mass; → satellite; → problem.

An operation designed to carry out the goals of a specific program, such as a a space flight or voyage.

Mission, from L. missionem (nominative missio) "act of sending," from mittere "to send," of unknown origin.

Gosilân, from gosil, variant gosi "sending away, dismission;" Mid.Pers. wisé "to despatch" (Parthian Mid.Pers. wsys- "to despatch;" Buddhist Mid.Pers. wsydy "to despatch;" Sogdian 'ns'yd- "to exhort"), from Proto-Iranian *vi-sid- "to despatch, send off," from prefix vi- "apart, away, out," + *sid- "to call" + -ân nuance suffix.

Spell a word wrongly.

→ mis-; → spell.

An → electromagnetic radiation emitted by → interstellar molecules through → transitions between → energy states of → molecules.

→ molecular; → emission.

A type of radioactive decay of atoms containing excess neutrons, in which a neutron is ejected from the nucleus.

→ neutron; → emission.

→ non-thermal radiation.

→ non-thermal; → emission.