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Juno, in astronomy

(Encyclopedia)Juno jo͞oˈnō [key], in astronomy, 3d asteroid to be discovered. It was found in 1804 by C. Harding. It has a diameter of c.120 mi (190 km). Its average distance from the sun is 2.67 astronomical un...

Vesta, in astronomy

(Encyclopedia)Vesta vĕsˈtə [key], in astronomy, the fourth asteroid to be discovered. It was found in 1807 by H. Olbers. It is the third largest asteroid in size, with a diameter of c.326 mi (525 km). Its averag...

Kirkwood gaps

(Encyclopedia)Kirkwood gaps, regions in the asteroid belt within which few asteroids are found. Astronomer Daniel Kirkwood first observed (1886) that few asteroids had an orbital period close to 1⁄2, 1⁄3, or 2...

Piazzi, Giuseppe

(Encyclopedia)Piazzi, Giuseppe jo͞ozĕpˈpā pyätˈtsē [key], 1746–1826, Italian astronomer, a Theatine priest from 1769. He became (1781) professor of mathematics at the Univ. of Palermo, supervised construct...

dwarf planet

(Encyclopedia)dwarf planet, a nonluminous body of rock or gas that orbits the sun and has a rounded shape due to its gravity. Unlike a planet, a dwarf planet is not capable of clearing its orbit of smaller objects ...

Ceres, in astronomy

(Encyclopedia)Ceres sîrˈēz [key], in astronomy, a dwarf planet, the first asteroid to be discovered. It was found on Jan. 1, 1801, by G. Piazzi. He took three distinct observations; on the basis of these the mat...

Schiaparelli, Giovanni Virginio

(Encyclopedia)Schiaparelli, Giovanni Virginio skyäpärĕlˈlē [key], 1835–1910, Italian astronomer. He was director (1862–1900) of the Brera Observatory, Milan. He is especially noted for having detected (18...

satellite, natural

(Encyclopedia)satellite, natural, celestial body orbiting a planet, dwarf planet, asteroid, or star of a larger size. The most familiar natural satellite is the earth's moon; thus, satellites of other planets are o...

cerium

(Encyclopedia)cerium sērˈēəm [key] [from the asteroid Ceres], metallic chemical element; symbol Ce; at. no. 58; at. wt. 140.116; m.p. 799℃; b.p. 3,426℃; sp. gr. 6.77 at 25℃; valence +3 or +4. Cerium is a ...

Tunguska Basin

(Encyclopedia)Tunguska Basin, c.400,000 sq mi (1,036,000 sq km), Krasnoyarsk Territory and Sakha Republic, E central Siberian Russia, between the Yenisei and Lena rivers. It has a huge untapped coal reserve. The ma...
 

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