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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...

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...

radio astronomy

(Encyclopedia)radio astronomy, study of celestial bodies by means of the electromagnetic radio frequency waves they emit and absorb naturally. Radio waves also come from outside the Milky Way. These extragalact...

opposition

(Encyclopedia)opposition, in astronomy, alignment of two celestial bodies on opposite sides of the sky as viewed from earth. Opposition of the moon or planets is often determined in reference to the sun. Only the s...

altitude

(Encyclopedia)altitude, vertical distance of an object above some datum plane, such as mean sea level or a reference point on the earth's surface. It is usually measured by the reduction in atmospheric pressure wit...

Suess, Eduard

(Encyclopedia)Suess, Eduard āˈdo͞oärt züs [key], 1831–1914, Austrian geologist, b. London. He was a professor (1857–1901) at the Univ. of Vienna and served for more than 20 years in the Austrian parliament...

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 ...

occultation

(Encyclopedia)occultation ŏkˌəltāˈshən [key], in astronomy, eclipse of one celestial body by another, e.g., when the moon lies between a star and the earth. Occultations of stars by the moon are important in ...

syzygy

(Encyclopedia)syzygy sĭzˈəjē [key], in astronomy, alignment of three bodies of the solar system along a straight or nearly straight line. A planet is in syzygy with the earth and sun when it is in opposition or...

parsec

(Encyclopedia)parsec pärˈsĕc [key] [parallax + second], in astronomy, basic unit of length for measuring interstellar and intergalactic distances, equal to 206,265 times the distance from the earth to the su...