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galactic coordinate system

(Encyclopedia)galactic coordinate system, astronomical coordinate system in which the principal axis is the galactic equator (the intersection of the plane of the Milky Way with the celestial sphere) and the refere...

Val-des-Sources

(Encyclopedia)Val-des-Sources, formerly Asbestos, town (1991 pop. 6,487), SE Que., Canada. Manufactures include wood products and electrical equipment. Asbestos, from which the town derived its former name, was lon...

Braun, Karl Ferdinand

(Encyclopedia)Braun, Karl Ferdinand broun [key], 1850–1918, German physicist. Braun taught at the Univ. of Marburg, Strasbourg Univ., Karlsruhe's Technische Hochschule, and the Univ. of Tübingen before being na...

Bloch, Felix

(Encyclopedia)Bloch, Felix, 1905–83, American physicist, b. Zürich, Switzerland, Ph.D. Univ. of Leipzig, Germany, 1928. He was a professor at Stanford from 1934 until his retirement in 1971. Bloch and Edward Pur...

Munk, Walter Heinrich

(Encyclopedia)Munk, Walter Heinrich, 1917–2019, American oceanographer and geophysicist, b. Vienna (then in Austria-Hungary), B.S. California Institute of Technology, 1939, Ph.D Univ. of California, Los Angeles, ...

Cassiopeia, in astronomy

(Encyclopedia)Cassiopeia, in astronomy, prominent northern constellation located almost directly opposite the Big Dipper across the north celestial pole. Five bright stars in the constellation form a rough W (or M)...

Kitt Peak National Observatory

(Encyclopedia)Kitt Peak National Observatory, astronomical observatory located southwest of Tucson, Ariz.; it was founded in 1958 under contract with the National Science Foundation and is administered by the Assoc...

Purcell, Edward Mills

(Encyclopedia)Purcell, Edward Mills, 1912–97, American physicist, b. Taylorville, Ill., Ph.D. Harvard, 1938. During World War II, Purcell was a researcher at the Massachusetts Institute of Technology Radiation La...

De Forest, Lee

(Encyclopedia)De Forest, Lee, 1873–1961, American inventor, b. Council Bluffs, Iowa, grad. Yale, 1896. He was a pioneer in the development of wireless telegraphy, sound pictures, and television. His triode (1906)...

echo, in acoustics

(Encyclopedia)echo, reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished. If a sound wave returns within 1⁄10 sec, the human ear is in...