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

A striking of a meteorite against another body, especially the solar system planets or satellites.

→ meteoritic; → impact.

The science or study of meteorites.

→ meteorite + → -ics.

A solid object in → interplanetary space before it reaches the Earth's atmosphere. Meteoroids are of → silicate and/or → metallic matter having a size from tiniest grains up to that of the smallest → asteroids.

→ meteor; → -oid.

The meteoroids distributed all along an → orbit and diffused somewhat around it.

→ meteoroid; → stream.

A relatively dense collection of meteoroids at certain spots along some → meteoroid streams.

→ meteoroid; → swarm.

Evaluation or measurement of one or more meteorological elements.

Meteorological, of or pertaining to → meteorology; → observation.

A scientific establishment dedicated to making precise and detailed meteorological observations and to studying and forecasting atmospheric phenomena by means of special equipments.

Meteorological, of or pertaining to → meteorology; → observatory.

The study of the physics, chemistry, and dynamics of the Earth's atmosphere, including the related effects at the air-earth boundary over both land and the oceans.

From Gk. meteorologia "discussion of celestial phenomena," from meteoron→ meteor + -logia, &rarr-logy.

Havâšenâsi, from havâ "weather, air," → air.

The → SI unit of length; symbol m. It is defined by taking the fixed numerical value of the → speed of light in vacuum, c, to be 299 792 458 when expressed in the unit m/s, where the → second is defined in terms of Δν_Cs.

From Fr. mètre, from Gk. metron "measure," from PIE base *me- "to measure" (cf. O.Pers., Av. mā- "to measure;" Skt. mati "measures;" L. metri "to measure").

Metr, loan from Fr.

A colorless, odorless, inflammable gas gas of formula CH₄; the simplest hydrocarbon.

From meth- a combining form representing methyl + -ane a suffix used in names of hydrocarbons of the methane or paraffin series.

Alcohol, also known as methyl alcohol, formula CH₃OH, formed in small quantities in the oxidation of methane. → methanol maser.

From → methane + -ol a suffix used in the names of chemical derivatives.

A maser source in which excited methanol molecules (CH₃OH) produce → maser emission. Methanol masers are signposts of the early stages of star formation, many being associated with sources that have not developed an → H II region. There are more than 20 different methanol transitions that have been observed. They are divided into two categories: Class I, excited by collisions, and class II, excited by infrared radiation. The most important class I masers are at a frequency of 44.1 GHz, while he most important class II masers are at a frequency of 6.7 GHz.

→ methanol; → maser.

A manner or mode of procedure, especially an orderly, logical, or systematic way of instruction, inquiry, investigation, experiment, and so on.

From M.Fr. méthode, from L. methodus "way of teaching or going," from Gk. methodus "scientific inquiry, method of inquiry," originally "following after," from → meta- "after" + hodos "way."

Raveš "mthod," originally "going, walking," from row "going," present stem of raftan "to go, walk;" Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack" + -eš a suffix of verbal nouns.

A method of fitting a curve to data points so as to minimize the sum of the squares of the distances of the points from the curve.

→ method; → least squares.

The linearization of the appropriate equations governing a system by the assumption of a steady state, with departures from that steady state limited to small perturbations. Also called perturbation method.

→ method; → small; → perturbation.

The solution of an equation or by proceeding from an initial approximation to a series of repeated trial solutions, each depending upon the immediately preceding approximation, in such a manner that the discrepancy between the newest estimated solution and the true solution is systematically reduced.

→ method; → successive; → approximation.

→ HD 140283.

Name given to → HD 140283 by the popular press due to its very old age. Methuselah is a biblical patriarch supposed to have lived 969 years (Genesis 5:21-27). The name Methuselah, or the phrase "old as Methuselah," is commonly used to refer to any living thing reaching great age.

A → methane molecule lacking one → hydrogen atom: CH₃. → methyl chloride.

Back formation from Fr. méthylène, → methylene.

A → chemical compound (CH₃Cl), which is the most abundant → organohalogen in the Earth's atmosphere. It has both natural and synthetic origins. Also called chloromethane. Low levels of methyl chloride occur naturally in the environment. Methyl chloride is formed in the oceans by natural processes (e.g., marine phytoplankton) and from biomass burning in grasslands and forested areas (e.g., forest fires); it has been detected at low levels in air all over the world. Other sources of exposure to methyl chloride include cigarette smoke, polystyrene insulation, and aerosol propellants; home burning of wood, coal, or certain plastics. High levels may occur at chemical plants where it is made or used. Acute (short-term) exposure to high concentrations of methyl chloride in humans has caused severe neurological effects. Methyl chloride has also caused effects on the heart rate, blood pressure, liver, and kidneys in humans (United States Environmental Agency, EPA).

→ methyl; → chloride.

The innermost moon of → Jupiter. Also known as Jupiter XVI. It was discovered in 1979 in images taken by Voyager 1. Its mass is about 3.6 × 10¹⁶ kg and its dimensions 60 × 40 × 34 km. Its mean distance from Jupiter is 128 000 km and its → orbital period is 0.29 Earth days, which is faster than Jupiter's rotation period. Metis is one of the → Shepherd moons of Jupiter.

Named in 1983 after the first wife of Zeus.