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weather satellite

(Encyclopedia)weather satellite, artificial satellite used to gather data on a global basis for improvement of weather forecasting. Information includes cloud cover, storm location, temperature, and heat balance in...

reconnaissance satellite

(Encyclopedia)reconnaissance satellite, artificial satellite launched by a country to provide intelligence information on the military activities of foreign countries. There are four major types. Early-warning sate...

Atget, Eugène

(Encyclopedia)Atget, Eugène özhĕnˈ ätzhĕˈ [key], 1857–1927, French photographer. After working as a sailor and then as an actor for many years, Atget became a photographer at the age of 42. He began at onc...

Ascension, island

(Encyclopedia)Ascension əsĕnˈchən [key], island, 34 sq mi (88 sq km), in the S Atlantic, NW of Saint Helena and belonging to the British St. Helena overseas territory. Georgetown i...

fog

(Encyclopedia)fog, aggregation of water droplets or ice crystals immediately above the surface of the earth (i.e., a cloud near the ground). A light or thin fog is usually called a mist. Fog may occur when the mois...

magnetron

(Encyclopedia)magnetron măgˈnĭtrŏnˌ [key], vacuum tube oscillator (see electron tube) that generates high-power electromagnetic signals in the microwave frequency range. Its operation is based on the combined ...

Bezos, Jeffrey Preston

(Encyclopedia)Bezos, Jeffrey Preston bāˈzōs [key], 1964– American business executive and on-line retailing pioneer, b. Albuquerque, N.M., grad. Princeton (B.S.E., 1986). He worked in computer technology for se...

chaos theory

(Encyclopedia)chaos theory, in mathematics, physics, and other fields, a set of ideas that attempts to reveal structure in aperiodic, unpredictable dynamic systems such as cloud formation or the fluctuation of biol...

hail, in meteorology

(Encyclopedia)hail, precipitation in the form of pellets composed of ice or of ice and snow, occurring at any time of the year, usually during the passage of a cold front or during a thunderstorm. Small hailstones ...

radar astronomy

(Encyclopedia)radar astronomy, application of radar to the determination of distances and planetary features within the solar system, such as rotation rates. A short burst of radio waves is transmitted in the direc...