long-period perturbation
1Perturbation (astronomy) — Perturbation is a term used in astronomy in connection with descriptions of the complex motion of a massive body which is subject to appreciable gravitational effects from more than one other massive body.[1] Such complex motions of a body can be …
2BKL singularity — A BKL (Belinsky Khalatnikov Lifshitz) singularityHarvnb|Belinsky|Khalatnikov|Lifshitz|1970] is a model of the dynamic evolution of the Universe near the initial singularity, described by a non symmetric, chaotic, vacuum solution to Einstein s… …
3Comet — This article is about the astronomical object. For other uses, see Comet (disambiguation). Comet Hale– …
4comet — cometary /kom i ter ee/, cometic /keuh met ik/, cometical, adj. cometlike, adj. /kom it/, n. Astron. a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and… …
5Flight dynamics — is the science of air and space vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle s center of mass, known as pitch , roll and yaw… …
6X-ray astronomy — X rays start at 0.008 nm and extend across the electromagnetic spectrum to 8 nm, over which the Earth s atmosphere is opaque. X ray astronomy is an observational branch of astronomy which deals with the study of X ray observation and detection… …
7Antarctica — /ant ahrk ti keuh, ahr ti /, n. the continent surrounding the South Pole: almost entirely covered by an ice sheet. ab. 5,000,000 sq. mi. (12,950,000 sq. km). Also called Antarctic Continent. * * * Antarctica Introduction Antarctica Background:… …
8Egypt — /ee jipt/, n. 1. Arab Republic of. a republic in NE Africa. 64,791,891; 386,198 sq. mi. (1,000,252 sq. km). Cap.: Cairo. Arabic, Misr. Formerly (1958 71), United Arab Republic. 2. an ancient kingdom in NE Africa: divided into the Nile Delta… …
9earthquake — /errth kwayk /, n. 1. a series of vibrations induced in the earth s crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating. 2. something that is severely disruptive; upheaval. [1300 50; ME erthequake …
10metamorphic rock — Any of a class of rocks that result from the alteration of preexisting rocks in response to changing geological conditions, including variations in temperature, pressure, and mechanical stress. The preexisting rocks may be igneous, sedimentary,… …
