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

Same as → macrostate.

→ macroscopic; → state.

Statistical physics: A state of a physical system that is described in terms of the system's overall or average properties at a macroscopic level (→ temperature, → pressure, → density, → internal energy, etc.). A macrostate will generally consist of many different → microstates. In defining a macrostate we ignore what is going on at the microscopic (atomic/molecular) level. The → probability of a certain macrostate is determined by how many microstates correspond to this macrostate. Therefore, the greater the number of microstates which lead to a particular macrostate, the greater the probability of observing that macrostate. Same as → macroscopic state. See also → entropy, → Boltzmann's entropy formula, → multiplicity.

→ macro-; → state.

The broadening of a star's → spectral lines due to → Doppler shifts from motions of different parts of the star's atmosphere.

→ macro; → turbulence.

1) Of, relating to, or named from, Ferdinand Magellan (see below).
2) Of or pertaining to characteristic of the → Magellanic Clouds.

Named in honor of Ferdinand Magellan (c. 1480-1521), the Portuguese navigator, who undertook the first voyage around the world. The two Clouds were first described by Magellan's chronicler Pigafetta, after leaving the Strait of Magellan in 1520; → -ic.

A filament of → neutral hydrogen which connects the → Small Magellanic Cloud and → Large Magellanic Cloud. The Magellanic Bridge appears to result from a → close encounter between these two galaxies some 200 million years ago.

→ Magellanic; → bridge.

Two irregular satellite galaxies of our own Galaxy which are visible from the Southern Hemisphere as misty patches in the night sky. → Large Magellanic Cloud; → Small Magellanic Cloud.

→ Magellanic; → cloud.

A class of low-mass galaxies with relatively rare features. In particular, these galaxies are characterized by a → stellar bar whose center is displaced from that of the disk and a one-armed spiral. The → Large Magellanic Cloud (LMC) is considered the prototype of this class of objects. However, despite a wealth of data, there is still a good deal of uncertainty concerning the nature of the LMC's bar. The majority of the observed Magellanic spirals in the nearby Universe share the LMC's structure, in particular the evidence of an offset bar and a one-armed spiral structure. A good example of these systems is NGC 3906, which shows evidence of the bar offset from the photometric center of the galaxy by 1.2 kpc (Pardy et al., 2016, ApJ 827, 149).

→ Magellanic; → spiral; → galaxy.

A thin trail of gas stretching from the → Magellanic System toward our own Galaxy over about 150° on the sky, corresponding to hundreds of thousands of light-years. This gas consists primarily of → neutral hydrogen and is thought to have originated from the Large and Small Magellanic Clouds as a result of tidal interactions with the Milky Way. See, e.g., Fox et al. 2013, arxiv/1304.4240, and references therein.

→ Magellanic; → stream.

A system consisting of the → Magellanic Clouds, the → Magellanic Bridge, and the → Magellanic stream.

→ Magellanic Clouds; → system.

A → metal-poor, → irregular galaxy like the → Large Magellanic Cloud or the → Small Magellanic Cloud. Other examples are: NGC 4449, NGC 4214, and NGC 3109.

→ Magellanic; → type; → galaxy.

1a) The power of apparently influencing events by using mysterious or supernatural forces.
1b) Mysterious tricks, such as making things disappear and reappear, performed as entertainment.
2) Having or apparently having supernatural powers (OxfordDictionaries.com)

M.E. magik(e) "witchcraft," from O.Fr. magique "magic, magical," from L.L. magice "sorcery, magic," from Gk. magike (tekhne "art"), from magos "one of the members of the learned and priestly class," from O.Pers. magu-, possibly from PIE root *magh- "to be able, have power."

Mid.Pers. yâtûk "wizard, sorcerer;" Av. yātu-

An n × n matrix in which every row, column, and diagonal add up to the same number.

→ magic; → square.

1) A civil officer charged with the administration of the law.
2) A minor judicial officer, as a justice of the peace or the judge of a police court, having jurisdiction to try minor criminal cases and to conduct preliminary examinations of persons charged with serious crimes (Dictionary.com).

M.E., from O.Fr. magistrat, from L. magistratus "a magistrate, public functionary," from magistrare "to serve as a magistrate," from magister, "chief, director," → master.

Dâdyâr, from dâd, → justice, + yâr, "assistant, helper," → gravity assist.

1) Molten → rock material that occurs below Earth's surface.
2) Molten material both below and on top of the surface of a → planet.

From L. magma "dregs of an ointment," from Gk. magma "an ointment," from root of massein "to knead, mold."

Mâgma, loanword from Fr.

A large cavity within the Earth's → crust containing → magma. When a → vent is opened to the surface, magma is extruded onto the surface as → lava.

→ magma; → chamber.

A metallic chemical element; symbol Mg. Atomic number 12; atomic weight 24.305; melting point about 648.8°C; boiling point about 1,090°C. The Scottish chemist Joseph Black recognized it as a separate element in 1755. In 1808, the English chemist Humphrey Davy obtained the impure metal and in 1831 the French pharmacist and chemist Antoine-Alexandre Brutus Bussy isolated the metal in the pure state.

The name originally used was magnium and was later changed to magnesium, which is derived from Magnesia, a district in the northeastern region of Greece called Thessalia.

An object that produces a magnetic field around itself.

From L. magnetum (nom. magnes) "lodestone," from Gk. ho Magnes lithos "the Magnesian stone," from Magnesia region in Thessaly where magnetized ore was obtained.

Âhanrobâ, literally "iron attracting, iron robbing," from âhan→ iron + robâ agent noun of robudan, robâyidan "to attract, to grab, rob;" Av. urūpaiieinti "to cause racking pain(?);" cf. Skt. rop- "to suffer from abdominal pain," rurupas "to cause violent pain," ropaná- "causing racking pain," rópi- "racking pain;" L. rumpere "to break;" O.E. reofan "to break, tear."
Meqnâtis, from Ar., from Gk., as above.

A highly magnetized → neutron star with fields a thousand times stronger than those of → radio pulsars. There are two sub-classes of magnetars, → anomalous X-Ray pulsar (AXP)s and → soft gamma repeater (SGR)s, that were thought for many years to be separate and unrelated objects. In fact SGRs and AXPs are both neutron stars possessing → magnetic fields of unprecedented strength of 10¹⁴ - 10¹⁶ G, and that show both steady X-ray pulsations as well as soft gamma-ray bursts. Their inferred steady X-ray luminosities are about one hundred times higher than their → spin-down luminosities, requiring a source of power well beyond the magnetic dipole spin-down that powers → rotation-powered pulsar (RPP)s. New high-energy components discovered in the spectra of a number of AXPs and SGRs require non-thermal particle acceleration and look very similar to high-energy spectral components of young rotation-powered pulsars (A. K. Harding, 2013, Front. Phys. 8, 679).

From magnet, contraction of → magnetic + -(s)tar, from → star.

Of or pertaining to a magnet or magnetism.

From → magnet + → -ic.

Meqnâtisi, meqnâti, from meqnâtis, → magnet; âhanrobâyik, from âhanrobâ, → magnet, + → -ik, → -ic.

The transport of the magnetic field by a fluid. It is given by the term ∇ x (v x B) in the → induction equation.

→ magnetic; → advection.