tondbâr-e partowhâ-ye keyhâni, ragbâ;r-e ~ ~
Fr.: gerbe (de rayons cosmiques)
Same as → cosmic-ray shower.
ragbâr-e peyšâri, ~ âbšâri
Multiple generations of secondary cosmic rays when the primary particles produce a succession of secondaries which have the same effects as the primary.
tondbâr-e partowhâ-ye keyhâni, ragbâr-e ~
Fr.: gerbe cosmique
An extensive (many kilometres wide) → cascade of ionized particles and electromagnetic radiation produced in the atmosphere when a → primary cosmic rays collides with atmospheric nuclei creating many → secondary cosmic rays. Also known as → air shower.
bârân-e šahâbi, ragbâr-e ~, tondbâr-e ~ (#)
Fr.: averse de météores, pluie de ~
An increased number of → meteors all appearing to → diverge from the direction of a single point, called → radiant. Meteor showers occur → annually on the same dates, when the Earth crosses through a → meteoroid stream. Meteor showers are named after the → constellation in which the radiant is located. For example, the → Perseids's radiant lies near the top of the constellation Perseus. Most meteor showers are caused by → comets. As a comet orbits the Sun it sheds an icy, dusty → debris stream along its orbit. When the Earth's orbit intersects the dust trail, more meteors are seen as the cometary debris encounters our planet's → atmosphere. In the case of the → Geminids and → Quadrantids, those meteor showers come from the debris scattered by orbiting → asteroids. Typical meteor showers show 15 to 100 meteors per hour at their peak. On very rare occasions, during a → meteor storm, thousands of meteors fall per hour. Prominent meteor showers are: → Quadrantids, → Lyrids, → Eta Aquariids, → Delta Aquariids, → Perseids, → Orionids, → Taurids, → Leonids, → Geminids, → Ursids, → Alpha Capricornids.
ragbâr, tondbâr (#)
Fr.: 1) averse; 2) gerbe
1) A brief, abrupt precipitation from a cloud, characterized by the suddenness
with which it begins and ends and by the rapid changes in intensity.
M.E. shour; O.E. scur "short fall of rain, fall of missiles or blows;" cf. O.N. skur, O.S., O.H.G. scur, Ger. Schauer.
šahâb-e bârâni, ~ ragbâri
Fr.: météore de la pluie, ~ ~ l'averse