xoršid-e nimšab (#)
Fr.: Soleil de minuit
The phenomenon occurring when the Sun is visible above the horizon at midnight. This phenomenon can be seen at positions north of the Arctic Circle and south of the Antarctic Circle when the Sun is circumpolar (around the summer solstice in the northern hemisphere and the winter solstice in the southern hemisphere respectively).
Fr.: diffusion de Mie
The scattering of → electromagnetic waves by → particles of → size comparable to the radiation → wavelength. Mie scattering depends weakly upon the wavelength, hence the → scattered light spectrum is similar to that of the → incident light. Mie scattering explains the → white color of clouds when scattering is due to → water droplets having a size of few microns. Cloud → droplets with a diameter of around 20 microns or so are large enough to scatter all visible wavelengths more or less equally. Because all wavelengths are scattered, clouds appear to be white. When clouds become very deep, less and less of the incoming solar radiation makes it through to the bottom of the cloud, which gives these clouds a darker appearance.
Named after Gustav Adolf Mie (1868-1957), a German physicist, whose theory of 1908 explains the process; → scattering.
Fr.: théorie de Mie
The explanation of the → scattering of → electromagnetic waves by → homogeneous spheres of arbitrary → size and → composition using analytical solutions of → Maxwell's equations. See also: → Mie scattering, → Rayleigh scattering.
Fr.: émigrer, immigrer
1) To go from one country, region, or place to another.
From L. migratus p.p. of migrare "to move from one place to another," ultimately from PIE *meigh- "to move, go;" cf. Gk. ameibein "to change," Iranian muž-, as below.
Mužidan, ultimately from Proto-Ir. *maij- "to move (to places);" cf. Parachi muž-, muš-, Yazghulami mûž- "to go," mexw-/maxwt- "to move, shake," Gilaki maxtan "to stroll," Gonâbâdi mejon "ague, shivering, shaking chills," Sangesari moj; cognate with L. migrare "to move, go," as below, Skt. niméghanāna- "moving down;" PIE *meigh- "to move, go."
mužeš, kuc (#)
1) The process or act of migrating; a migratory movement.
Migrating; periodically migrating; pertaining to migration.
→ migrate + -ory, an adj.-forming suffix.
Mikulski Archive for Space Telescopes (MAST)
Bâygâni-ye Mikulski barâye teleskophâ-ye fazâyi
Fr.: Archive Mikulski pour télescopes spatiaux
A → NASA funded project to support and provide to the astronomical community a variety of astronomical data archives, with the primary focus on scientifically related data sets in the optical, ultraviolet, and near-infrared parts of the spectrum. MAST is a huge database that contains astronomical observations of stars, planets and galaxies from 16 separate NASA space science missions, including the Hubble Space Telescope. It is located at the Space Telescope Science Institute (STScI).
Fr.: cycles de Milankovitch
The theory according to which variations in the elements of Earth-Sun geometry are responsible for the sequence of ice ages during the Pleistocene era. The main elements are the varying tilt of the Earth's rotational axis, and the varying eccentricity of the Earth's orbit.
Named after the Serbian mathematician Milutin Milankovitch (1879-1958), who introduced the concept during the first half of the twentieth century.
An opaque white fluid secreted by female mammals for the nourishment of their young.
M.E.; O.E. meol(o)c, (Anglian) milc; cf. Gr. Milch, Goth. miluks; akin to L. mulgere, Gk amelgein "to milk;" PIE base *melg- "wiping, stroking;"
Šir "milk;" Mid.Pers. šir; (Parth. šyft); Khotanese švida; Sogd. xšiβd (Yaghnobi xšift; Yadgha xšira); Av. xšvid-, xšvipta-; cf. Skt. ksira- "milk."
Râh-e Širi (#)
Fr.: Voie lactée
The diffuse glowing band of light seen on dark nights spanning the sky as a great circle. It is produced by light from stars and nebulae in the → Galactic plane. The apparent form of the Milky Way in the sky results from a geometrical effect created by our location in the outlying regions of a huge, flattened disk of stars. → Milky Way galaxy.
From L.L. galaxias "Milky Way," from Gk. galaxis kyklos
"emilky circle," from gala (gen. galaktos) "milk."
Râh, → way; širi, adj. of šir "milk;" Mid.Pers. šir; cf. Skt. ksira- "milk."
Milky Way galaxy
kahkešân-e râh-e širi (#)
Fr.: Voie lactée
A → spiral galaxy, of which the
→ solar system is a small part.
It is the second largest in our → Local Group of galaxies.
The Milky Way is a disk-shaped system,
with a diameter of between 80,000 and 100,000 → light-years
and a thickness of about 2,000 light-years, containing more than
1011 stars. The stars are divided into two main categories,
→ Population II stars and
→ Population I stars.
Milky Way system
râžmân-e râh-e širi
Fr.: Voie lactée
The huge star system of which the Sun is a member. Same as the Galaxy or the Milky Way galaxy.
Fr.: expérience de Miller-Urey
A chemical experiment conducted in 1953 that aimed at checking Alexander Oparin's and J. B. S. Haldane's hypothesis that under putative conditions present in the atmosphere of the early Earth inorganic molecules would spontaneously form organic molecules. Miller and Urey filled a sterile flask with a mixture of water, ammonia, methane, and hydrogen. The mixture was heated to evaporate water to produce water vapor. High-voltage electric sparks were passed through the mixture to simulate lightning. After a week, contents were analyzed. Amino acids, the building blocks for proteins, were found.
Named after Stanley L. Miller (1930-2007) and Harold C. Urey (1893-1981); → experiment.
Prefix meaning one thousandth (10-3).
From Fr., from L. mille "thiusand."
Mili-, loan from Fr.
One thousandth of a bar; a unit of atmospheric pressure. The average atmospheric pressure at sea level is 1.01325 bars or 1013.25 mb.
Millikan's oil-drop experiment
âzmâyeš-e Millikan (#)
Fr.: expérience de Millikan
A precision experiment for measuring the → electron charge. By studying the falling speed of small charged droplets in the gravitational field of the Earth subjected to an adjustable electric field, Millikan (1909) was able to demonstrate conclusively the discrete nature of electric charge, and moreover measure the charge of an individual electron.
Robert Andrews Millikan (1868-1953); → experiment.
mowj-e milimetri (#)
Fr.: onde millimétrique
Microwaves with wavelengths between 1 and 10 millimeter, corresponding to frequencies between 300 GHz to 30 GHz. → millimeter-wave astronomy.
axtaršenâsi-ye mowjhâ-ye milimetri (#)
Fr.: astronomie millimétrique
That part of radio astronomy which uses electromagnetic waves in the range 1-10 millimeter to study various components of the Universe, in particular the chemistry of interstellar matter.
A thousand thousand (106).
O.Fr. million, from It. millione, literally "a great thousand," augmentative of mille "thousand," from L. mille.
Milyon, Loan from Fr.
pulsâr-e milisâniyé (#), tapâr-e ~ (#)
Fr.: pulsar milliseconde
A type of pulsar that spins around its axis every few thousands of a second. The prototype 1937+21, discovered in 1982, has a period of 1.56 milliseconds; i.e. it spins more than 600 times per second, the fastest so far found (Backer et al. 1982, Nature 300, 615). These pulsars are distinguished from typical pulsars by the extreme stability of their rotation period. It is thought that they have been rejuvenated by a "spin-up process" involving the accumulation of matter from a companion star. → recycled pulsar.