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Persian Gulf

(Encyclopedia)Persian Gulf, arm of the Arabian Sea, 90,000 sq mi (233,100 sq km), between the Arabian peninsula and Iran, extending c.600 mi (970 km) from the Shatt al Arab delta to the Strait of Hormuz, which link...

guided missile

(Encyclopedia)guided missile, self-propelled, unmanned space or air vehicle carrying an explosive warhead. Its path can be adjusted during flight, either by automatic self-contained controls or remote human control...

Kepler's laws

(Encyclopedia)CE5 Schematic representation of Kepler's second law: The areas ABF and A′B′F′ are equal and are swept out in equal intervals of time by a planet orbiting around the sun (at F). Kepler's laws...

chromosphere

(Encyclopedia)chromosphere krōˈməsfērˌ [key] [Gr.,=color sphere], layer of rarefied, transparent gases in the solar atmosphere; it measures 6,000 mi (9,700 km) in thickness and lies between the photosphere (th...

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...

lens, in optics

(Encyclopedia)CE5 Lenses lens, device for forming an image of an object by the refraction of light. In its simplest form it is a disk of transparent substance, commonly glass, with its two surfaces curved or wi...

submersible

(Encyclopedia)submersible, small, mobile undersea research vessel capable of functioning in the ocean depths. Development of a great variety of submersibles during the later 1950s and 1960s came about as a result o...

Veda

(Encyclopedia)Veda vāˈdə, vēˈdə [key] [Sanskrit,=knowledge, cognate with English wit, from a root meaning know], oldest scriptures of Hinduism and the most ancient religious texts in an Indo-European language...

court

(Encyclopedia)court, in law, official body charged with administering justice. The term is also applied to the judge or judges who fill the office and to the courtroom itself. Courts come into existence when legal ...

clock

(Encyclopedia)CE5 A pendulum clock: Weight-driven clock mechanism clock, instrument for measuring and indicating time. Predecessors of the clock were the sundial, the hourglass, and the clepsydra. See also watc...