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universal time

(Encyclopedia)universal time (UT), the international time standard common to every place in the world, it nominally reflects the mean solar time along the earth's prime meridian (renumbered to equate to civil time)...

Dyson, Sir Frank Watson

(Encyclopedia)Dyson, Sir Frank Watson dīˈsən [key], 1868–1939, English astronomer, b. Ashby-de-la-Zouch, grad. Cambridge. He was astronomer royal of Scotland (1905–10) and of England (from 1910). As director...

Eudoxus of Cnidus

(Encyclopedia)Eudoxus of Cnidus yo͞odŏkˈsəs, nīˈdəs [key], 408?–355? b.c., Greek astronomer, mathematician, and physician. From the accounts of various ancient writers, he appears to have studied with Plat...

Foucault, Jean Bernard Léon

(Encyclopedia)Foucault, Jean Bernard Léon zhäN bĕrnärˈ lāôNˈ fo͞okōˈ [key], 1819–68, French physicist. Known especially for his research on the speed of light, he determined its velocity in air and fou...

Greenwich mean time

(Encyclopedia)Greenwich mean time or Greenwich meridian time (GMT), the former name for mean solar time at the site of the Royal Observatory in Greenwich, England, which is located on the prime meridian. In 1925 th...

Lamont, Johann von

(Encyclopedia)Lamont, Johann von yōˈhän fən läˈmônt [key], 1805–79, Scottish-German astronomer and magnetician, b. Scotland. In 1817 he went to Ratisbon to study at the seminary. He remained in Germany to ...

Yerkes, Charles Tyson

(Encyclopedia)Yerkes, Charles Tyson yûrˈkēz, –kəs [key], 1837–1905, American financier, b. Philadelphia. He began his business career as a clerk in a Philadelphia grain commission house. He became a broker ...

Brashear, John Alfred

(Encyclopedia)Brashear, John Alfred brəshērˈ [key], 1840–1920, American maker of scientific instruments and educator, b. Brownsville, Pa. A mechanic by trade, he taught himself the art of making lenses and mir...

Bhaskara

(Encyclopedia)Bhaskara əchärˈyə [key] [Skt.,=learned], b. 1114, Indian mathematician and astronomer. According to the custom, he put his learned treatises into verse, adding, however, explanations in prose. His...

Sitter, Willem de

(Encyclopedia)Sitter, Willem de vĭlˈəm də sĭtˈər [key], 1872–1934, Dutch astronomer and mathematician. He was professor from 1908 at the Univ. of Leiden and in 1919 became director of its observatory. His ...