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blackbody

(Encyclopedia)blackbody, in physics, an ideal black substance that absorbs all and reflects none of the radiant energy falling on it. Lampblack, or powdered carbon, which reflects less than 2% of the radiation fall...

Giorgione

(Encyclopedia)Giorgione jōrjôˈnā [key], c.1478–1510, Venetian painter, b. Castelfranco Veneto; fellow student of Titian under Giovanni Bellini in Venice. Giorgione was known also as Zorgo or Zorgi da Castelfr...

Pedro I

(Encyclopedia)Pedro I (Dom Pedro de Alcântara) pāˈdrō [key], 1798–1834, first emperor of Brazil (1822–31); son of John VI of Portugal. Dom Pedro was a child when the Portuguese royal family, fleeing from Na...

Cathari

(Encyclopedia)Cathari kăthˈərī [key] [Gr.,=pure], name for members of the widespread dualistic religious movement of the Middle Ages. Carried from the Balkans to Western Europe, Catharism flourished in the 12th...

Revelation

(Encyclopedia)Revelation or Apocalypse əpŏkˈəlĭps [key], the last book of the New Testament. It was written c.a.d. 95 on Patmos Island off the coast of Asia Minor by an exile named John, in the wake of local p...

geometry

(Encyclopedia)geometry [Gr.,=earth measuring], branch of mathematics concerned with the properties of and relationships between points, lines, planes, and figures and with generalizations of these concepts. Eucli...

Greek art

(Encyclopedia)Greek art, works of art produced in the Aegean basin, a center of artistic activity from very early times (see Aegean civilization). This article covers the art of ancient Greece from its beginnings t...

map

(Encyclopedia)map, conventionalized representation of spatial phenomena on a plane surface. Unlike photographs, maps are selective and may be prepared to show various quantitative and qualitative facts, including b...

Sahara

(Encyclopedia)Sahara səhârˈə [key] [Arab.,=desert], world's largest desert, c.3,500,000 sq mi (9,065,000 sq km), N Africa; the western part of a great arid zone that continues into SW Asia. Extending more than ...

Ikhnaton

(Encyclopedia)Ikhnaton äˌkənäˈtən [key] [Egyptian,=Aton is satisfied], d. c.1354 b.c., king of ancient Egypt (c.1372–1354 b.c.), of the XVIII dynasty; son and successor of Amenhotep III. His name at his acc...