Planet

Planet, in the solar system, 1 of the 9 major celestial bodies (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto) orbiting the sun; by extension, a similar body circling any other star. In 1963 it was discovered that Barnard's Star has at least 1 companion about 1.5 times the size of Jupiter, and in 1983 scientists detected possible evidence of an evolving planetary system around the star Vega.

See also: Solar System.