Columbia Encyclopedia

Search results

325 results found

Jupiter, in astronomy

(Encyclopedia)Jupiter jo͞oˈpətər [key], in astronomy, 5th planet from the sun and largest planet of the solar system. Astronomers have discovered 79 satellites orbiting Jupiter, but five of those, small sate...

science

(Encyclopedia)science [Lat. scientia=knowledge]. For many the term science refers to the organized body of knowledge concerning the physical world, both animate and inanimate, but a proper definition would also hav...

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...

particle accelerator

(Encyclopedia)CE5 Linear accelerator (LINAC) CE5 Cyclotron: As the charged particles move faster, they spiral out to the edge of the Ds. particle accelerator, apparatus used in nuclear physics to produce bea...

satellite, artificial

(Encyclopedia)CE5 A. Nimbus weather satellite B. Syncom communications satellite satellite, artificial, object constructed by humans and placed in orbit around the earth or other celestial body (see also space ...

lead, chemical element

(Encyclopedia)lead, metallic chemical element; symbol Pb [Lat. plumbum]; at. no. 82; at. wt. 207.2; m.p. 327.502℃; b.p. about 1,740℃; sp. gr. 11.35 at 20℃; valence +2 or +4. One of the oldest metals used by h...

environmentalism

(Encyclopedia)environmentalism, movement to protect the quality and continuity of life through conservation of natural resources, prevention of pollution, and control of land use. The philosophical foundations for ...

art conservation and restoration

(Encyclopedia)art conservation and restoration, the preservation of structurally sound works of art, the halting of processes that lead to the damage of works of art, and the repair of already damaged works of art....

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...

earth, in geology and astronomy

(Encyclopedia)CE5 A. Cross section of the earth, showing its shells B. Detailed cross section of the crust and upper mantle: The lithosphere consists of the hard rock in the crust and upper mantle, lying above t...