[plan-i-ter-ee] /ˈplæn ɪˌtɛr i/
of, relating to, or resembling a or the .
Machinery. noting or pertaining to an epicyclic gear train in which a sun gear is linked to one or more gears also engaging with an encircling ring gear.
Machinery. a planetary gear train.
of or relating to a planet
wandering or erratic
(astrology) under the influence of one of the planets
(of a gear, esp an epicyclic gear) having an axis that rotates around that of another gear
(of an electron) having an orbit around the nucleus of an atom
noun (pl) -taries
a train of planetary gears
1590s; see planet + -ary. Probably from Late Latin planetarius “pertaining to a planet or planets,” but this is attested only as “an astrologer.” Planetary nebula, so called for its shape, attested from 1785.
A large celestial body, smaller than a star but larger than an asteroid, that does not produce its own light but is illuminated by light from the star around which it revolves. In our solar system there are nine known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Because of Pluto’s small size—about two-thirds the diameter of Earth’s moon—and its unusual orbit, many astronomers believe it should actually be classed as a Kuiper belt object rather than a planet. A planetlike body with more than about ten times the mass of Jupiter would be considered a brown dwarf rather than a planet. See also extrasolar planet, inner planet, outer planet.
noun, Astronomy. 1. an expanding shell of thin ionized gas that is ejected from and surrounds a hot, dying star of about the same mass as the sun; the gas absorbs ultraviolet radiation from the central star and reemits it as visible light by the process of fluorescence. noun 1. an expanding shell of gas […]
noun, Astronomy. 1. the small component of the precession of the equinoxes contributed by the motion of the ecliptic, the change in orientation of the plane of the earth’s orbit being produced by the gravitational attraction of the planets.
[plan-i-tes-uh-muh l] /ˌplæn ɪˈtɛs ə məl/ Astronomy noun 1. one of the small celestial bodies that, according to one theory (planetesimal hypothesis) were fused together to form the of the solar system. adjective 2. of or relating to a planetesimal or planetesimals. planetesimal (plān’ĭ-těs’ə-məl) Any of innumerable small bodies of accreted gas and dust thought […]
noun, Machinery. 1. any of the gears in an epicyclic train surrounding and engaging with the sun gear.