Columbia Encyclopedia

Search results

500 results found

Neptune, in astronomy

(Encyclopedia)Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolut...

X-ray astronomy

(Encyclopedia)X-ray astronomy, study of celestial objects by means of the X rays they emit, in the wavelength range from 0.01 to 10 nanometers. X-ray astronomy dates to 1949 with the discovery that the sun emits X ...

echidna, in zoology

(Encyclopedia)echidna ĭkĭdˈnə [key] or spiny anteater, animal of the order Monotremata, the egg-laying mammals. A short-legged, grayish brown animal, the echidna is covered with sharp quills and can protect its...

corundum

(Encyclopedia)corundum kərŭnˈdəm [key], mineral, aluminum oxide, Al2O3. The clear varieties are used as gems and the opaque as abrasive materials. Corundum occurs in crystals of the hexagonal system and in mass...

cyanobacteria

(Encyclopedia)cyanobacteria sīˌənōbăktĭrˈēə, sī-ănˌō– [key] or blue-green algae, photosynthetic bacteria that contain chlorophyll. For many years they were classified in the plant kingdom along with ...

Chesterton, G. K.

(Encyclopedia)Chesterton, G. K. (Gilbert Keith Chesterton), 1874–1936, English author. Conservative, even reactionary, in his thinking, Chesterton was a convert (1922) to Roman Catholicism and its champion. He ha...

chicle

(Encyclopedia)chicle chĭkˈəl [key], name for the gum obtained from the latex of the sapodilla tree (Manilkara zapota), a tropical American evergreen. The sapodilla (known also by many other common names) is wide...

Hughes, Howard Robard

(Encyclopedia)Hughes, Howard Robard, 1905–76, U.S. business executive, b. Houston. As a young man he inherited (1925) the patent rights to an oil tool drill, which, manufactured by the Hughes Tool Company, formed...

hydra, in zoology

(Encyclopedia)hydra hīˈdrə [key], common name for freshwater organisms in the phylum Cnidaria, which includes jellyfish, sea anemones, and corals. Hydras are widely distributed in lakes, ponds, and sluggish stre...

Hampton, Lionel

(Encyclopedia)Hampton, Lionel, 1908?–2002, African-American vibraphonist and bandleader, b. Louisville, Ky. When his family moved to Chicago c.1916, the young Hampton began playing drums in a newsboys' band. He m...