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National Science Foundation

(Encyclopedia)National Science Foundation (NSF), an independent agency in the executive branch of the U.S. federal government concerned with promoting a national science policy by supporting basic research and educ...

culminate

(Encyclopedia)culminate, in astronomy, the maximum height in the sky reached by a celestial body on a given day. At the culminate the body is crossing the observer's celestial meridian and is said to be in upper tr...

Tereshkova, Valentina Vladimirovna

(Encyclopedia)Tereshkova, Valentina Vladimirovna, 1937–, Soviet cosmonaut. She was the first woman to orbit the earth, in Vostok 6 on June 16–19, 1963. She left the Soviet space program soon after and married c...

Nut, in Egyptian religion

(Encyclopedia)Nut no͝ot, nŭt [key], in Egyptian religion, sky-goddess. She was the sister-wife of the earth god Geb, to whom she bore Osiris, Isis, Set, and Nephthys. She was sometimes represented with her hands ...

sidereal period

(Encyclopedia)sidereal period, in astronomy, length of time a body takes to complete an orbit relative to the fixed stars. See sidereal time. ...

asthenosphere

(Encyclopedia)asthenosphere ăsthēnˈəsfēr [key], region in the upper mantle of the earth's interior, characterized by low-density, semiplastic (or partially molten) rock material chemically similar to the overl...

eider, in zoology

(Encyclopedia)eider: see duck.

diet, in nutrition

(Encyclopedia)diet, food and drink regularly consumed for nourishment. Nutritionists generally recommend eating a wide variety of foods; however, some groups of people survive on a very limited diet. The traditiona...

dike, in technology

(Encyclopedia)dike, in technology: see levee.

dimension, in mathematics

(Encyclopedia)dimension, in mathematics, number of parameters or coordinates required locally to describe points in a mathematical object (usually geometric in character). For example, the space we inhabit is three...