1) A broad glowing arc of radiance, sometimes seen high in the
western sky at → twilight,
caused by the → scattering effect of
→ fine dust particles
suspended in the → upper atmosphere.
Fr.: luminescence nocturne
The faint ever-present glow in the → night time → sky caused by the → collision of → atoms and → molecules in Earth's → upper atmosphere with high energy → particles and → radiation, mainly from the → Sun. The airglow, also called nightglow, varies with time of night, → latitude, and → season.
Same as → gegenschein.
1) foruz, foruq, foruzeš; 2) foruzidan
Fr.: 1) rougoiement, incandescence, éclat; 2) rougeoyer, s'embraser, être incandescent, luire rouge
1a) A light emitted by or as if by a substance heated to luminosity; incandescence.
1b) Brightness of color.
M.E. glowen, from O.E. glowan "to shine as if red-hot," ultimately from PIE *ghlo-.
Foruz-, foruzidan, afruxtan "to light, kindle;" related to foruq "light, brightness" (Mid.Pers. payrog "light, brightness"); rôšan "light; bright, luminous;" ruz "day;" Mid.Pers. rošn light; bright," rôc "day;" O.Pers. raucah-; Av. raocana- "bright, shining, radiant," raocah- "light, luminous; daylight;" cf. Skt. rocaná- "bright, shining, roka- "brightness, light;" Gk. leukos "white, clear;" L. lux "light," also lumen "light, window," luna "Moon;" E. light; Ger. Licht; Fr. lumière; PIE base *leuk- "light, brightness."
lunar horizon glow
foruq-e ofoq-e mâh
Fr.: éclat de l'horizon lunaire
A very bright crescent of light glowing on the lunar horizon at → sunset or just before → sunrise. It has been suggested that → lunar dust is transported electrically high into sky, allowing sunlight to scatter and create glows. On the day side of the → Moon, solar → ultraviolet radiation is strong enough to kick → electrons from → dust grains in the lunar soil. Removal of electrons, which have a negative electric charge, leaves the dust with a positive electric charge. Since like charges repel, the positively charged dust particles get pushed away from each other, and the only direction not blocked by more dust is up. In the 1960s, Surveyor probes filmed a glowing cloud floating just above the lunar surface during sunrise. Later, Apollo 17 astronaut Gene Cernan, while orbiting the Moon, recorded a similar phenomenon at the sharp line where lunar day meets night, called the → terminator.
Fr.: luminescence nocturne
Same as → airglow.
nur-e šahr, foruq-e âsmân
Fr.: illumination du ciel
The illumination of the night sky in urban areas caused by wasted light shining upward scattered off dust, humidity, and air. Skyglow is a type of → light pollution that results from light fixtures emitting a portion of their light directly upward into the sky. Light scattered in the atmosphere creates an orange-yellow glow above a city or town. Skyglow interferes with sensitive astronomical instruments designed to capture light from distant stars, nebulae, and galaxies. Skyglow can often be detected hundreds of kilometers away.