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

The larger of the two Magellanic Cloud galaxies visible in the southern hemisphere at about 22 degrees from the South Celestial Pole. It is approximately on the border between the constellations → Dorado and → Mensa in a region of faint stars. The center of the LMC is approximately RA: 5h 23m 35s, dec: -69° 45' 22''. The LMC shines with a total → apparent visual magnitude of approximately zero. It spans an area of the sky about 9 by 11 degrees, corresponding to about 30,000 → light-years across in the longest dimension, for a distance of some 162,000 light-years. It has a visible mass of about one-tenth that of our own Galaxy (10¹⁰ Msun). The LMC and its twin, the → Small Magellanic Cloud, are two of our most prominent Galactic neighbors. The LMC is classified as a disrupted → barred spiral galaxy of type SBm, the prototype of a class of → Magellanic spirals. The galaxy is characterized by a prominent offset → stellar bar located near its center with the dominant → spiral arm to the north with two "embryonic" arms situated to the south. The → metallicity in the LMC is known to be lower than in the solar neighborhood by a factor 2 or more. Based on 20 → eclipsing binary systems, the distance to the LMC is measured to one percent precision to be 49.59±0.09 (statistical) ±0.54 (systematic) kpc (Pietrzynski et al., 2019, Nature 567, 200).

→ large; → Magellanic; → cloud.

1) General: An act or mode of linking; the fact of being linked.
2) Physics: The amount of magnetic flux passing through a coil of wire or other electric circuit.

From → link + -age a suffix of abstract nouns from O.Fr.

From ham-, → com-, + peyvand, → link, + noun suffix -y.

A roughly 400-year period from the mid-16th through the mid-19th centuries when temperatures over much of Europe were unusually cold. Glaciers in the Alps advanced and European rivers froze much more often than during the past century. Harvests failed, livestock perished, and poor people suffered from famine and disease. The Little Ice Age coincided with two successive low → solar activity periods, the → Sporer minimum and the → Maunder minimum.

→ little; → ice; → age.

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.

To direct or control the use of; to exercise executive, administrative, and supervisory direction of.

Probably from It. maneggiare "to handle, train (a horse)," from L. manus "hand."

Gonârdan, from Mid.Pers vinârtan, variant vinâristan "to organize, arrange, put in order," from vi- "apart, away from" (Av. vi- "apart, away from, out;" O.Pers. viy- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + âristan, ârâstan "to arrange, adorn;" O.Pers. râs- "to be right, straight, true," râsta- "straight, true" (Mod.Pers. râst "straight, true"), râd- "to prepare," Av. râz- "to direct, put in line, set," Av. razan- "order," Gk. oregein "to stretch out," L. regere "to lead straight, guide, rule," p.p. rectus "right, straight," Skt. rji- "to make straight or right, arrange, decorate," PIE base *reg- "move in a straight line."

The act or manner of managing; handling, direction, or control.

Verbal noun of → manage.

A person who manages; a person who has controls or directs an institution, a team, a division, or part it.

Agent noun of → manage.

The moment when a celestial object crosses an observer's meridian. Same as meridian transit.

→ meridian; → passage.

1) General: A piece of information (written, spoken, or by signals).
2) Computer science: A defined amount of information, coded or not, between machines or machines and men. → information theory.

M.E., from O.Fr. message "message, news, embassy," from M.L. missaticum, from L. missus "a sending away, dispatching," from mittere "to send," → mission.

Payâm, variants payqâm, peyqâm, Mid.Pers. paygâm, ultimately from *patigam-, literally "arriving, newcomer," from *pati- "to, toward, at, in," → ad hoc, + *gam- "to come," → heliosheath.

Any language that is used to describe a language. See also → object language.

→ meta-; → language.

An optical phenomenon caused by → refraction of light in the lowest layers of the Earth's → atmosphere especially in the → desert, over a hot pavement, or at → sea. Due to temperature variations, the air → density varies, leading to a spatial variation of the → index of refraction of → air. As a result, light from a single point takes more than one path to the observer and the → image of some distant object appears displaced from its true position; the image may appear distorted, inverted, or wavering.

From Fr. mirage, from (se) mir(er) "to look at (oneself), be reflected" (from L. mirare "to wonder at, admire") + suffix -age.

Sarâb "mirage," literally "water point, water origin, water head," probably from sar "origin, beginning," → head, + âb, → water. The similarity with Ar. serab (cf. Hebrew sharab "burning heat, parched ground") may be fortuitous.

1) The number of days that have elapsed since the last → conjunction of the Sun and Moon. It is 7 days at → first quarter, 15 days at → full moon, and 22 days at → third quarter.
2) The time past since the → formation of the Moon.

→ Moon; → age.

1) Kohan-ruzi literally "age in days," from kohan-ruz "old in days," from kohan "old, ancient," kohné "worn;" Mid.Pers. kahwan "old, aged, worn;" pir; Mid.Pers. pir "old, aged, ancient;" Av. parô (adv.) "before, before (of time)," in front (of space); cf. Skt. puáh, combining form of puras "before (of time and place), in front, in advance;" mâh, → Moon.
2) Senn, → age.

Linguistics: A language that has evolved naturally as a means of communication among people, as opposed to → artificial language and → formal language (Dictionary.com).

→ natural; → language.

Fluctuations of electric potential in a physical system due to spontaneous disturbances in the system.

→ noise; → voltage.