Columbia Encyclopedia

Search results

500 results found

ultraviolet astronomy

(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...

colloid

(Encyclopedia)colloid kŏlˈoid [key] [Gr.,=gluelike], a mixture in which one substance is divided into minute particles (called colloidal particles) and dispersed throughout a second substance. The mixture is also...

laser

(Encyclopedia)CE5 Ordinary light sources produce incoherent light, while a laser produces a beam of coherent light. laser [acronym for light amplification by stimulated emission of radiation], device for the cr...

Ukraine

(Encyclopedia)CE5 Ukraine yo͞oˈkrān, yo͞okrānˈ [key], Ukr. Ukraina, republic (2015 est. pop. 44,658,000), 232,046 sq mi (601,000 sq km), E Europe. It borders on Poland in the northwest; on Slovakia, Hungar...

electrode

(Encyclopedia)electrode, terminal through which electric current passes between metallic and nonmetallic parts of an electric circuit. In most familiar circuits current is carried by metallic conductors, but in som...

corona, in astronomy

(Encyclopedia)corona, luminous envelope surrounding the sun, outside the chromosphere. Its density is less than one billionth that of the earth's atmosphere. The corona is visible only at the time of totality durin...

Colchester

(Encyclopedia)Colchester kōlˈchĭstər, –chĕsˌtər [key], city and district, Essex, SE Englan...

Fort Worth

(Encyclopedia)Fort Worth, city (2020 pop. 918,915), seat of Tarrant co., N Tex., on the Trinity River 30 mi (48 km) W of Dallas; settled 1843, inc. 1873. An army post...

Fresno

(Encyclopedia)Fresno frĕzˈnō [key], city (2020 pop. 546,770), seat of Fresno co., S central Calif.; inc....

Peace

(Encyclopedia)Peace, river, 945 mi (1,521 km) long, formed by the junction of the Finlay and Parsnip rivers at Williston Lake, N central British Columbia, Canada. It flows east through the Rocky Mts., then generall...