Columbia Encyclopedia

(Encyclopedia) Pluto, in astronomy, a dwarf planet and the first Kuiper belt, or transneptunian, object (see comet) to be discovered (1930) by astronomers. Pluto has an elliptical orbit usually lying beyond that of ...

(Encyclopedia) Charon, in astronomy, the natural satellite, or moon, of Pluto. ...

(Encyclopedia) Pluto, in Greek religion and mythology, god of the underworld, son of Kronos and Rhea; also called Hades. After the fall of the Titans, Pluto and his brothers Zeus and Poseidon divided the universe, a...

(Encyclopedia) Eris, in astronomy, the largest known dwarf planet. Eris, whose highly eccentric elliptical orbit ranges from 38 AU to 97 AU and is inclined more than 44°, is the largest known object of the Kuiper b...

(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...

(Encyclopedia) Neptune, in astronomy, 8th planet from the sun at a mean distance of about 2.8 billion mi (4.5 billion km) with an orbit lying between those of Uranus and the dwarf planet Pluto; its period of revolut...

(Encyclopedia) Lowell, Percival, 1855–1916, American astronomer, b. Boston, grad. Harvard, 1876; brother of Abbott Lawrence Lowell and Amy Lowell. He visited Korea and Japan, where he acted as counselor and foreig...

(Encyclopedia) astronomy, branch of science that studies the motions and natures of celestial bodies, such as planets, stars, and galaxies; more generally, the study of matter and energy in the universe at large. ...

(Encyclopedia) infrared astronomy, study of celestial objects by means of the infrared radiation they emit, in the wavelength range from about 1 micrometer to about 1 millimeter. All objects, from trees and building...

(Encyclopedia) coma, in astronomy: see comet.