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planet

(Encyclopedia)planet [Gr.,=wanderer], a large nonluminous body of rock, gas, or ice that orbits the sun or another star, has a rounded shape due to gravity, and has cleared its orbit of smaller objects. The term, o...

cosmology

(Encyclopedia)cosmology, area of science that aims at a comprehensive theory of the structure and evolution of the entire physical universe. The earliest pre-Ptolemaic theories assumed that the earth was the cent...

radioactivity

(Encyclopedia)CE5 Effects of a magnetic field on the products of radioactivity CE5 Disintegration series: Radioactive decay of radium-226 into lead-206 radioactivity, spontaneous disintegration or decay of t...

Mississippi, river, United States

(Encyclopedia)Mississippi, river, principal river of the United States, c.2,350 mi (3,780 km) long, exceeded in length only by the Missouri, the chief of its numerous tributaries. The combined Missouri-Mississippi ...

international law

(Encyclopedia)international law, body of rules considered legally binding in the relations between national states, also known as the law of nations. It is sometimes called public international law in contrast to p...

Hitler, Adolf

(Encyclopedia)Hitler, Adolf äˈdôlf hĭtˈlər [key], 1889–1945, founder and leader of National Socialism (Nazism), and German dictator, b. Braunau in Upper Austria. By July, 1944, the German military si...

asteroid

(Encyclopedia)CE5 The asteroid belt lies between the orbits of Mars and Jupiter. Gaps where no asteroids are found are called Kirkwood gaps. The Trojan asteroids share Jupiter's orbit with the planet. asteroid,...

Korea

(Encyclopedia)CE5 Korea kôrēˈə, kə– [key], Korean Hanguk or Choson, region and historic country (85,049 sq mi/220,277 sq km), E Asia. A peninsula, 600 mi (966 km) long, Korea separates the Sea of Japan (c...

Greenland

(Encyclopedia)Greenland, Green. Kalaallit Nunaat, Dan. Grønland, the largest island in the world (2015 est. pop. 56,000), 836,109 sq mi (2,166,086 sq km), self-governing overseas administrative division of Denmark...

solar system

(Encyclopedia)CE5 Solar system CE5 solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the ...