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

One thousands of a → sievert.

→ milli- + → sievert.

A design of → radio interferometer made of two lines of → antennae at right angles to one another.

Named after the Australian engineer and astronomer Bernard Yarnton Mills (1920-2011; see R.H. Frater et al. 2013, arXiv:1306.6371); → cross.

Same as → Milne Universe.

→ Milne Universe; → cosmological; → model.

A model of the → Universe which is devoid of matter and where the → space-time is → open (Ω_M = 0, Ω_R = 0, Ω_Λ = 0, k = -1). The Universe will expand at a constant rate for ever. See also → empty Universe, → de Sitter Universe.

Put forward by Edward Arthur Milne (1896-1950), a British astrophysicist, who introduced the → cosmological principle; → cosmological; → model.

The approximation of a stellar atmosphere with a plane parallel grey atmosphere in radiative equilibrium. It is assumed that a spectral is formed in such a way that the ratio of the line absorption coefficient to the continuous absorption coefficient is constant with depth.

→ Milne Universe; Arthur Stanley Eddington (1882-1944), prominent British astrophysicist; → approximation.

The seventh of Saturn's known satellites. It is 392 km in diameter and orbits Saturn at a mean distance of 185,520 km. Mimas' low density (1.17) indicates that it is composed mostly of water ice with only a small amount of rock. The surface is saturated with impact craters, dominated by the largest one measuring 130 km across, known as Herschel. Mimas was discovered in 1789 by Herschel.

In Gk. mythology, Mimas was one of the Gigantes slain by Hephaestus, the god of fire, volcanism, smiths and craftsmen, with barrage of red-hot metal.

1) The human faculty to which are ascribed thought, feeling, etc; often regarded as an immaterial part of a person (Dictionary.com).
2) Psychology: The totality of conscious and unconscious → mental processes and activities (Dictionary.com).

M.E. mynd(e), from O.E. gemynd "memory, remembrance; thought, purpose" (cf. Gothic muns "thought," munan "to think;" ON minni "mind;" Ger. Minne (archaic) "love," originally "memory"), from PIE root *men- "think, remember;" cf. Pers. mân, man "mind, thought;" Av. man- "to think;" Skt. matih "thought," Gk. mania "madness," mentio "remembrance;" Lith. mintis "thought, idea," O.C.S. mineti "to believe, think," Russ. pamjat "memory."

Ment, from Mid.Pers. mênitan "to think," Av. mainyeite "he thinks;" O.Pers. man- "to think," maniyaiy "I think," Ardumaniš- (proper noun) "upright-minded," Haxāmaniš- (proper noun, Hellenized Achaemenes, founder of the Achaemenian dynasty) "having the mind of a friend;" Av. mân- "to think," manah- "mind, thinking, thought; purpose, intention," mainyu- "mind, mentality, mental force, inspiration," cf. Sogdian mân "mind;" Skt. man- "to think," mánye "I think," manyate "he thinks," mánas- "intelligence, understanding, conscience;" Gk. mainomai "to be angry," mania "madness," mantis "one who divines, prophet;" L. mens "mind, understanding, reason," memini "I remember," mentio "remembrance;" Lith. mintis "thought, idea;" Goth. muns "thought," munan "to think;" Ger. Minne "love," originally "loving memory;" O.E. gemynd "memory, thinking, intention;" PIE base *men- "to think, mind; spiritual activity."

A naturally occurring inorganic solid. The internal crystalline structure of a mineral is controlled by its elemental composition.

From M.L. minerale "something mined," from neuter of mineralis "pertaining to mines," from minera "mine."

Kâni "mineral," from kân "mine," from kandan "to dig" (Mid.Pers. kandan "to dig;" O.Pers. kan- "to dig," akaniya- "it was dug;" Av. kan- "to dig," uskən- "to dig out" (→ ex- for prefix us-); cf. Skt. khan- "to dig," khanati "he digs").

A black hole of mass as low as 10^-6 gram supposed to have formed in the early Universe following the Big Bang event. Same as primordial black hole.

Mini a shortening of → minimum; → black hole.

The least value attained (or attainable) by a function; the opposite of maximum.

From L. minimum "smallest" (thing), neuter of minimus "smallest," superlative of → minor "smaller."

Kaminé, from kamin superlative of kam "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few." Keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") + -é nuance suffix.

Same as → angle of minimum deviation.

→ minimum; → deviation.

The minimum distance between the paths of two orbiting objects around a → primary. Such distance between an object and Earth is called Earth MOID.

→ minimum; → orbit; → intersection; → distance.

The amount of hydrogen necessary to form a star; more specifically the minimum mass to ignite → hydrogen fusion. → Hydrogen burning will start at a limit of about 0.08 Msun, or 75 → Jupiter masses. Below 0.08 Msun, the core never gets hot enough to trigger → hydrogen fusion. → Protostars less massive than this limit are known as → brown dwarfs or → planets if the mass is less than 13 Jupiter masses. Above 13 Jupiter masses, some minor nuclear reactions (→ deuterium burning) occur that do not provide much energy. The minimum mass for → star formation is a critical parameter with profound astrophysical, cosmological, and even anthropic consequences.

→ minimum; → stellar; → mass.

1) A → quasar of lesser power compared to ordinary quasars hypothesized to exist at early cosmic times. According to some models, the Universe was reionized by a population of miniquasars powered by → intermediate-mass black holes.
2) Same as → microquasar.

Mini a shortening of → minimum; → quasar.

Same as → space-time diagram.

→ Minkowski metric; → diagram.

The → metric that belongs to a four-dimensional → flat manifold and is given by ds² = - dt² + dx² + dy² + dz². Three coordinates represent → space and the fourth coordinate is devoted to → time. The Minkowski metric underlies the → geometry of → special relativity. Compare → Robertson-Walker metric.

In honor of Hermann Minkowski (1864-1909), Russian-born German mathematician, who introduced the concept of the four-dimensional nature of space-time; → metric.

A completely flat four-dimensional space, which contains no gravitating matter, used in the theory of special relativity.

→ Minkowski metric; → space-time.

A peculiar blue object near the → elliptical galaxy NGC 541 in the → galaxy cluster Abell 194. According to several pieces of evidence, the → starburst in Minkowski's object was triggered by the → radio jet emerging from the → nucleus of the nearby → active galaxy NGC 541. This is similar to the jet-induced → star formation associated with → Centaurus A, and the radio-aligned star forming regions in powerful radio galaxies at → high redshift. Absorption and emission line measurements and broadband → SED fitting, give an age of around 7.5 Myr for Minkowski's object.

Minkowski, R., 1958, PASP, 70, 143; → object.

Lesser or smaller in amount, extent, or size.

From L. minor "lesser, smaller, junior," from PIE base *mei- "small" (cf. L. minuere "make small;" Gk. meion "less," minuthein "to lessen;" Skt. miyate "diminishes, declines;" O.E. minsian "to diminish").

Kehin comparative and superlative of keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," kam "little, few; deficient, wanting; scarce," (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few;" from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") + -é nuance suffix.

The axis of an ellipse that is perpendicular to the major axis at a point equidistant from the foci.

→ minor; → axis.