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perihelion

(Encyclopedia)perihelion pĕrˌəhēˈlēən [key], point nearest the sun in the orbit of a body about the sun. See apsis. ...

solar wind

(Encyclopedia)solar wind, stream of ionized hydrogen—protons and electrons—with an 8% component of helium ions and trace amounts of heavier ions that radiates outward from the sun at high speeds. The continuous...

perturbation

(Encyclopedia)perturbation pŭrˌtərbāˈshən [key], in astronomy and physics, small force or other influence that modifies the otherwise simple motion of some object. The term is also used for the effect produce...

parallax

(Encyclopedia)CE5 The trigonometric parallax of a star, expressed by the angle θ, is a measure of its apparent motion against the background of more distant stars as a result of the earth's motions in its orbit...

aphelion

(Encyclopedia)aphelion əfēˈlēən, ăpˌhēˈ– [key], point farthest from the sun in the orbit of a body about the sun. See apsis. ...

astronomical unit

(Encyclopedia)astronomical unit (AU), mean distance between the earth and sun; one AU is c.92,960,000 mi (149,604,970 km). The astronomical unit is the principal unit of measurement within the solar system, e.g., M...

Institute for Advanced Study

(Encyclopedia)Institute for Advanced Study, at Princeton, N.J.; chartered 1930, opened 1933. It differs from a university in that it offers no curriculum or examinations, and confers no degrees. Founded with a gift...

time and motion study

(Encyclopedia)time and motion study, analysis of the operations required to produce a manufactured article in a factory, with the aim of increasing efficiency. Each operation is studied minutely and analyzed in ord...

Nippon

(Encyclopedia)Nippon nĭpˈŏn, nĭpŏnˈ [key], name for Japan, derived from Dai Nippon, meaning Great Japan. The expression comes from the Chinese ideograph for the place where the sun comes from, or Land of the ...

heliotrope

(Encyclopedia)heliotrope hēˈlēətrōpˌ [key] [Gr.,=sun-turning] or turnsole, name for any plant that turns to face the sun, especially members of the genus Heliotropium of the family Boraginaceae. The garden he...