Columbia Encyclopedia
Search results
56 results found
Ptolemaic system
(Encyclopedia)Ptolemaic system tŏlˌəmāˈĭk [key], historically the most influential of the geocentric cosmological theories, i.e., theories that placed the earth motionless at the center of the universe with a...black hole
(Encyclopedia)black hole, in astronomy, celestial object of such extremely intense gravity that it attracts everything near it and in some instances prevents everything, including light, from escaping. The term was...Hegel, Georg Wilhelm Friedrich
(Encyclopedia)Hegel, Georg Wilhelm Friedrich gāˈôrkh vĭlˈhĕlm frēˈdrĭkh hāˈgəl [key], 1770–1831, German philosopher, b. Stuttgart; son of a government clerk. Hegel has influenced many subsequent p...non-Euclidean geometry
(Encyclopedia)non-Euclidean geometry, branch of geometry in which the fifth postulate of Euclidean geometry, which allows one and only one line parallel to a given line through a given external point, is replaced b...fundamentalism
(Encyclopedia)fundamentalism. 1 In Protestantism, religious movement that arose among conservative members of various Protestant denominations early in the 20th cent., with the object of maintaining traditional int...astronomy
(Encyclopedia)astronomy, branch of science that studies the motions and natures of celestial bodies, such as planets, stars, and galaxies; more generally, the study of matter and energy in the universe at large. ...relativity
(Encyclopedia)relativity, physical theory, introduced by Albert Einstein, that discards the concept of absolute motion and instead treats only relative motion between two systems or frames of reference. One consequ...observatory
(Encyclopedia)observatory, scientific facility especially equipped to detect and record naturally occurring scientific phenomena. Although geological and meteorological observatories exist, the term is generally ap...radio astronomy
(Encyclopedia)radio astronomy, study of celestial bodies by means of the electromagnetic radio frequency waves they emit and absorb naturally. Radio waves also come from outside the Milky Way. These extragalact...Neoplatonism
(Encyclopedia)Neoplatonism nēˌōplāˈtənĭzəm [key], ancient mystical philosophy based on the doctrines of Plato. Neoplatonism was an early influence on Christian thinkers. The Christian apologists Clement...Browse by Subject
- Earth and the Environment +-
- History +-
- Literature and the Arts +-
- Medicine +-
- People +-
- Philosophy and Religion +-
- Places +-
- Africa
- Asia
- Australia and Oceania
- Britain, Ireland, France, and the Low Countries
- Commonwealth of Independent States and the Baltic Nations
- Germany, Scandinavia, and Central Europe
- Latin America and the Caribbean
- Oceans, Continents, and Polar Regions
- Spain, Portugal, Italy, Greece, and the Balkans
- United States, Canada, and Greenland
- Plants and Animals +-
- Science and Technology +-
- Social Sciences and the Law +-
- Sports and Everyday Life +-
