Columbia Encyclopedia

Search results

500 results found

Doppler effect

(Encyclopedia)Doppler effect, change in the wavelength (or frequency) of energy in the form of waves, e.g., sound or light, as a result of motion of either the source or the receiver of the waves; the effect is nam...

Ryle, Sir Martin

(Encyclopedia)Ryle, Sir Martin, 1918–84, British radio astronomer, B.S. Oxford, 1939. Ryle was a researcher and professor at Cambridge from 1945 until his retirement in 1982. Knighted in 1966, he was Britain's As...

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)...

short waves

(Encyclopedia)short waves, radio waves whose frequencies range from about 3 to 25 megahertz (Mhz), corresponding roughly to the high-frequency band (see radio frequency). When they impinge on certain layers of the ...

Möbius, Augustus Ferdinand

(Encyclopedia)Möbius, Augustus Ferdinand mōˈbēəs, Ger. möˈbēəs [key],(1790–1868), German mathematician and astronomer, b. Schulpforta, Saxony. A professor of astronomy at the Univ. of Leipzig, he made im...

broadcasting

(Encyclopedia)broadcasting, transmission, usually using radio frequencies, of sound or images to a large number of radio or television receivers. In the United States the first regularly scheduled radio broadcasts ...

interference

(Encyclopedia)CE5 Constructive interference: Two crests or two troughs meet and combine (A, B, C). Destructive interference: A crest and a trough meet and cancel each other (D, E, F). interference, in physics, ...