Columbia Encyclopedia

(Encyclopedia) solstice sŏlˈstĭs [key] [Lat.,=sun stands still], in astronomy, either of the two points on the ecliptic that lie midway between the equinoxes (separated from them by an angular distance of 90°). ...

(Encyclopedia) radar, system or technique for detecting the position, movement, and nature of a remote object by means of radio waves reflected from its surface. Although most radar units use microwave frequencies, ...

(Encyclopedia) da Silva, Luiz Inácio lo͞oēshˈ ēnäsˈyo͞o dä sēlˈvə [key], 1945–, Brazilian labor leader and politician, known as Lula, b. Vargem Grande (now Caetés), Pernambuco. Born into a poor family...

(Encyclopedia) bromine brōˈmēn, –mĭn [key] [Gr.,=stench], volatile, liquid chemical element; symbol Br; at. no. 35; at. wt. 79.904; m.p. –7.2℃; b.p. 58.78℃; sp. gr. of liquid 3.12 at 20℃; density of va...

(Encyclopedia) Sagan, Carl Edward sāˈgən [key], 1934–96, American astronomer and popularizer of science, b. New York City. Early in his career he investigated radio emissions from Venus and concluded that the c...

(Encyclopedia) Struve shtro͞oˈvə [key], family of astronomers. Friedrich Georg Wilhelm von Struve, 1793–1864, was born in Germany but later lived in Russia. While director (1817–39) of Dorpat Observatory he w...

(Encyclopedia) revolution, in a political sense, fundamental and violent change in the values, political institutions, social structure, leadership, and policies of a society. The totality of change implicit in this...

(Encyclopedia) zero, that number which, when added to any number, leaves the latter unchanged; its symbol is 0. The introduction of zero into the decimal system was the most significant achievement in the developmen...

(Encyclopedia) Barnard, Frederick Augustus Porter, 1809–89, American educator and mathematician, b. Sheffield, Mass., grad. Yale, 1828. After tutoring at Yale and teaching in institutions for the deaf and mute, he...

(Encyclopedia) Wisconsin, University of, main campus at Madison; land-grant and state supported; coeducational; chartered 1848, opened 1849. Its history was disturbed by storms over the policies of Glenn Frank and o...