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variable star

(Encyclopedia)variable star, star that varies, either periodically or irregularly, in the intensity of the light it emits. Other physical changes are usually correlated with the fluctuations in brightness, such as ...

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 ...

opal

(Encyclopedia)opal ōˈpəl [key], a mineral consisting of poorly crystalline to amorphous silica, SiO2·nH2O; the water content is quite variable but usually ranges from 3% to 10%. Common opal is usually colorless...

long march

(Encyclopedia)long march, Chin., Changzheng, the journey of c.6,000 mi (9,660 km) undertaken by the Red Army of China in 1934–35. When their Jiangxi prov. Soviet base was encircled by the Nationalist army of Chia...

Shreveport

(Encyclopedia)Shreveport shrēvˈpôrt [key], city (1990 pop. 198,525), seat of Caddo parish, NW La., on the Red River near the Tex. and Ark. lines; inc. 1839. The third largest city in the state, it is a regional ...

porgy

(Encyclopedia)porgy pôrˈgē [key], common name for members of the Sparidae, a family of small-mouthed fishes with strong teeth adapted for crushing their food of shellfish and crustaceans. Porgies are found in wa...

Akron

(Encyclopedia)Akron ăkˈrən [key], city (2020 pop. 190,469), seat of Summit co., NE Ohio, on the Little Cuyahoga River; inc. 1865. Once the heart of the nation's rubber industry, Akro...

Fert, Albert

(Encyclopedia)Fert, Albert älbârˈ fâr [key], 1938– French physicist, b. Carcassonne, France. After receiving his Ph.D. at the Univ. of Paris-Sud in 1970 Fert accepted a teaching position there and headed a re...

Hertzsprung, Ejnar

(Encyclopedia)Hertzsprung, Ejnar īˈnär hĕrtsˈspro͞ong [key], 1873–1967, Danish astronomer. Although trained as a chemical engineer, Hertzsprung made his career in astronomy, specializing in exacting photogr...

Hadar, in astronomy

(Encyclopedia)Hadar or Beta Centauri bāˈtə sĕntôrˈē [key], bright star in the constellation Centaurus; 1992 position R.A. 14h01.7m, dec. −60°13′. A bluish-white giant of spectral class B1 II, it has an ...