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fiber optics

(Encyclopedia)fiber optics, transmission of digitized messages or information by light pulses along hair-thin glass or plastic fibers. Each fiber is surrounded by a cladding having a high index of refractance so th...

Boucher, François

(Encyclopedia)Boucher, François fräNswäˈ bo͞oshāˈ [key], 1703–70, French painter. Boucher's art embodied the spirit of his time; it was elegant, frivolous, and artificial. He studied briefly with François...

Ter Borch, Gerard

(Encyclopedia)Ter Borch or Terborch, Gerard gāˈrärt tərbôrkhˈ [key], 1617–81, Dutch genre and portrait painter. He studied with his father and traveled throughout Europe, showing extraordinary precocity in ...

stereoscope

(Encyclopedia)stereoscope stĕrˈēəskōpˌ [key], optical instrument that presents to a viewer two slightly differing pictures, one to each eye, to give the effect of depth. In normal vision the two eyes, being a...

Callahan, Harry Morey

(Encyclopedia)Callahan, Harry Morey, 1912–99, American photographer, b. Detroit. Self-taught, he began taking pictures (1938) as a hobby and, inspired by the work of Ansel Adams, began to produce professional-qua...

weather satellite

(Encyclopedia)weather satellite, artificial satellite used to gather data on a global basis for improvement of weather forecasting. Information includes cloud cover, storm location, temperature, and heat balance in...

Betjeman, Sir John

(Encyclopedia)Betjeman, Sir John bĕtˈjəmən [key], 1906–84, English poet, b. London. Traditional in rhyme and meter, his verse combined a witty appraisal of the English present with nostalgia for England's pas...

Morley, Edward Williams

(Encyclopedia)Morley, Edward Williams, 1838–1923, American scientist, b. Newark, N.J., grad. Williams College, 1860. From 1869 to 1906 he was professor of chemistry at Western Reserve College (now Case Western Re...

anomalistic year

(Encyclopedia)anomalistic year ənŏmˌəlĭsˈtĭk [key], time required for the earth to go from the perihelion point once around the sun and back to the perihelion point. It is 365 days, 6 hr, 13 min, 53.0 sec of...

ephemeris time

(Encyclopedia)ephemeris time (ET), astronomical time defined by the orbital motions of the earth, moon, and planets. The earth does not rotate with uniform speed, so the solar day is an imprecise unit of time. Ephe...