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dark matter

(Encyclopedia)dark matter, material that is believed to make up nearly 27% of the mass of the universe but is not readily visible because it neither emits nor reflects electromagnetic radiation, such as light or ra...

continental drift

(Encyclopedia)CE5 Continental drift (arrows indicate the directions of motion of the landmasses) A. Proposed reconstruction of the supercontinent Pangaea indicating the major present landmasses B. Proposed recon...

Smuts, Jan Christiaan

(Encyclopedia)Smuts, Jan Christiaan yän krĭsˈtyän smŭts [key], 1870–1950, South African statesman and soldier, b. Cape Colony. Of Boer (Afrikaner) stock but a British subject by birth, he was educated at Vic...

Rhodophyta

(Encyclopedia)Rhodophyta rōdŏfˈətə [key], phylum (division) of the kingdom Protista consisting of the photosynthetic organisms commonly known as red algae. Most of the world's seaweeds belong to this group. Me...

Vicksburg campaign

(Encyclopedia)Vicksburg campaign, in the American Civil War, the fighting (Nov., 1862–July, 1863) for control of the Mississippi River. The Union wanted such control in order to split the Confederacy and to resto...

zirconium

(Encyclopedia)zirconium zərkōˈnēəm [key], metallic chemical element; symbol Zr; at. no. 40; at. wt. 91.224; m.p. about 1,852℃; b.p. 4,377℃; sp. gr. 6.5 at 20℃; valence +2, +3, or +4. Zirconium is a very ...

migration

(Encyclopedia)migration, of people, geographical movements of individuals or groups for the purpose of permanently resettling. Normal internal migration has been characterized by a population shift from rural t...

Harlem Renaissance

(Encyclopedia)Harlem Renaissance, term used to describe a flowering of African-American literature and art in the 1920s, mainly in the Harlem district of New York City. During the mass migration of African American...

Darwin, Charles Robert

(Encyclopedia)Darwin, Charles Robert, 1809–82, English naturalist, b. Shrewsbury; grandson of Erasmus Darwin and of Josiah Wedgwood. He firmly established the theory of organic evolution known as Darwinism. He st...

Pentecostalism

(Encyclopedia)Pentecostalism, worldwide 20th–21st-century Christian movement that emphasizes the experience of Spirit baptism, generally evidenced by speaking in tongues (glossolalia). The name derives from Pente...