500 results found
Pallas(Encyclopedia)Pallas pl´s [key], in astronomy, 2d asteroid to be discovered. It was found in 1802 by H. Olbers. The second largest asteroid, it has a diameter of c.300 mi (480 km). Its orbit has a semimajor ax...
Pallas(Encyclopedia)Pallaspl´s, in classical mythology. 1 Name given to Athena after she killed either a youthful playmate named Pallas or, in some legends, the giant Pallas. 2 Goatish giant killed by Athena when he...
Pallas, Peter Simon(Encyclopedia)Pallas, Peter Simon p´tr z´môn pä´läs [key], 1741–1811, German naturalist and explorer. He became (1768) professor at the Academy of Sciences, St. Petersburg. In 1769, Pallas was a membe...
astronomy(Encyclopedia)astronomy, branch of science that studies the motions and natures of celestial bodies, such as planets, stars, and galaxies; more generally, the study of matter and energy in the universe at large. An...
In(Encyclopedia)In, symbol for the element indium.
radar astronomy(Encyclopedia)radar astronomy, application of radar to the determination of distances and planetary features within the solar system, such as rotation rates. A short burst of radio waves is transmitted in the direc...
radio astronomy(Encyclopedia)radio astronomy, study of celestial bodies by means of the electromagnetic radio frequency waves they emit and absorb naturally. Radio Telescopes Radio waves emanating from celestial bodies are receiv...
ultraviolet astronomy(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...
neutrino astronomy(Encyclopedia)neutrino astronomy, study of stars by means of their emission of neutrinos, fundamental particles that result from nuclear reactions and are emitted by stars along with light. Approximately 100 billio...
infrared astronomy(Encyclopedia)infrared astronomy, study of celestial objects by means of the infrared radiation they emit, in the wavelength range from about 1 micrometer to about 1 millimeter. All objects, from trees and building...
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