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ELL Earth Sci 29
The Solar System
Term | Definition |
---|---|
geocentric | Earth-centered model of the solar system |
heliocentric | Sun-centered model of the solar system |
ellipse | oval shape pattern traveled by planets around the Sun |
aphelion | point in the orbit of a planet at which it is farthest from the Sun |
perihelion | point in the orbit of a planet at which it is closest to the Sun |
astronomical unit | average distance from the Earth to the Sun, approximately 143.5 million km |
orbit period | time required for a planet to make on revolution around the Sun (measured in Earth days or years) |
inertia | tendency of a moving body to remain in motion until an outside force acts upon it |
terrestrial planets | planets with properties similar to those of the Earth (Mercury, Venus, & Mars) |
Jovian planets | gaseous planets with star-like qualities (Jupiter, Saturn, Uranus, & Neptune) |
day | the amount of time for a planet to make one complete rotation on its axis |
year | the amount of time for a planet to make one complete orbit around the Sun |
asteroids | a fragment of rock that orbits the Sun |
asteroid belt | the region between the orbits of Mars and Jupiter in which most asteroids are formed |
Trojan asteroids | asteroid that orbits the Sun just ahead or behind the planet Jupiter |
earth-grazer asteroids | asteroid that orbits the Sun in an elongated ellipse that may pass close to the Earth and the Sun |
comet | body of rock, dust, methane, ammonia and ice that revolves around the Sun in a long, elliptical orbit |
coma | spherical cloud of gas and dust that surrounds the nucleus of a comet |
Oort cloud | spherical cloud of dust and ice surrounding the solar system that may contain as many as a trillion comets |
meteoroid | small bit of rock or metal moving through the solar system left by a comet or produced by a collision between asteroids |
meteor | a bright streak of light caused when a meteoroid burns up in the Earth's atmosphere |
meteorite | meteoroid or part of a meteoroid left after it hits the Earth's surface |