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

A suffix of nouns indicating state, condition, or quality, or the result or product of an action.

From Fr., from L. -mentum.

A combining form meaning "measure," used in the names of instruments measuring quantity, extent, degree.

From Fr. -mètre; → meter.

Suffix -sanj, present stem of sanjidan "to measure; to compare," from Mid.Pers. sanjidan "to weigh," from present tense stem sanj-, Av. θanj- "to draw, pull;" Proto-Iranian *θanj-. Other terms from this base in Pers.: lanjidan "to pull up," hanjidan, âhanjidan "to draw out," farhang "education, culture."

A suffix with the meaning "the process of measuring."

→ -meter + -y a suffix used in the formation of action nouns.

-sanji, from sanj, → -meter, + -i a suffix of verbal nouns.

A star whose spectrum is dominated by the absorption bands of → titanium oxide (TiO) and → vanadium oxide (VO) and has many neutral metal lines. The → effective temperature of M dwarfs ranges from about 3850 to 2600 K. They are low mass stars with masses ranging from 0.6 times that of the Sun at spectral type M0 to less than 0.1 → solar masses. M dwarfs are very abundant, they account for about 70-80% of stars in the → Galactic disk. The nearest star to the Sun, → Proxima Centauri, is an M dwarf.

M, letter of alphabet in the → Harvard classification; → dwarf.

A cool, red star of spectral type M with a surface temperatures of less than 3600 K. The spectra of M stars are dominated by molecular bands, especially those of TiO. Naked-eye examples are Betelgeuse and Antares.

M, letter of alphabet, → star.

A type of → asteroid that consists of metallic → iron and displays high → albedo (0.10-0.18). M-type asteroids inhabit the middle part of the → asteroid belt.

M for → metallic; → type; → asteroid.

An → open cluster in the constellation → Serpens associated with the → Eagle Nebula. It is usually mistakenly stated as being that nebula. Also called NGC 6611. First discovered by Philippe Loys de Chéseaux in 1745-6.

Object bearing the number 16 in the → Messier catalog.

Half of the vertex angle of the → Mach cone generated by a body in → supersonic flight. It is given by sin μ = (a/v), where a is the speed of the sound waves and v the velocity of the object. In terms of Mach number: μ = asin (1/M). The Mach angle diminishes with the object velocity. For M = 1 it is 90°, for M = 2, it is 30°, and for M = 5, its is 11.5°.

→ Mach number; → angle.

The cone that confines the pressure disturbance created by a → supersonic object moving in a → compressible medium.

→ Mach number; → cone.

Same as → shock diamond.

So named because Ernst Mach (1838-1916) was the first to record its existence.

The ratio of the speed of a moving object to the → sound speed in the medium through which the object is traveling.

Named after the Austrian physicist Ernst Mach (1838-1916); → number.

The envelope of wave fronts created by a → supersonic source.

→ Mach number; → wave.

The local → inertial frame and the → inertia of any body results from the distribution of all matter in the Universe. This principle has been neither confirmed nor refuted.

→ Mach number; → number.

1) An apparatus consisting of interrelated parts with separate functions, used in the performance of some kind of work.
2) A device that transmits or modifies force or motion.

From M.Fr. machine "device, contrivance," from L. machina "machine, fabric, device, trick," from Doric Gk. makhana, Attic Gk. mekhane "device, means," related to mekhos "means, expedient," from PIE *maghana- "that which enables," from base *magh- "to be able, have power" (cf. O.C.S. mogo "be able," O.E. mæg "I can").

Mâšin, loanword from Fr.

A collective term for objects that reside in the → halo of a galaxy (in particular → brown dwarfs) and which do not emit enough radiation to be detected from Earth. MACHOs can be spotted using the technique of → microlensing.

Acronym from Massive Astrophysical Compact Halo Objects.

A → Taylor series that is expanded about the reference point zero.

Named after Colin Maclaurin (1698-1746), a Scottish mathematician.

A combining form meaning "large, long, great, excessive," used in the formation of compound words; opposite of → micro-.

From Gk. makros "long, large," from PIE base *mak-/*mek- "long, thin" (cf. L. macer "lean, thin;" O.N. magr, O.E. mæger "lean, thin").

Dorošt "large; rough, fierce," from Mid.Pers. društ "harsh, coarse;" O.Pers. darš- "to dare," daršam (adv.) "mightily;" Av. darš- "to dare," darši-, daršita- "bold, strong;" cf. Skt. dhars- "to be bold, courageous, to attack," dhrsita- "bold, daring;" Gk. thrasys "bold;" O.E. durran; E. dare.

The great world or Universe; the Universe considered as a whole (opposed to → microcosm).
A representation of a smaller unit or entity by a larger one, presumably of a similar structure.

→ macro-; → cosmos.

A stellar → explosion with energies between those of a → nova and a → supernova and observationally distinguished by being brighter than a typical nova (M_V ~ -8 mag) but fainter than a typical supernova (M_V ~ -19 mag) (Kulkarni 2005; arXiv:astro-ph/0510256).

→ macro-; → nova.

Of or relating to scales large enough to be visible to the naked eye or under low order of magnification. Compare → microscopic. → microscopic state.

→ macro-; → -scope + → -ic.