Earth Science 4: Nine Planets: Vocabulary
Terms
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- the point nearest to the sun in the orbit of a planet or comet
- perihelion
- the occasional apparent backward movement of the superior planets from east to west
- retrograde motion
- a planet whose orbit is outside the earth's orbit
- superior planet
- one of the nine most massive bodies orbiting the sun
- planet
- the point at which light rays come together after being bent by a lens or curved mirror; one or two points used in drawing an ellipse
- focus (plural, foci)
- the dark region of separation in the ring system of Saturn
- Cassini's division
- the mass of an object per volume
- density
- the average distance between the earth and the sun (150 million km or 93 million mi)
- A.U. (astronomical unit)
- the point furthest from the sun in the orbit of a planet or comet
- aphelion
- the ability of an object such as a planet or minor planet to reflect light
- albedo
- the downward pull of an astronomical body on objects located at its surface
- surface gravity
- a measure of the amount of material an object contains, irrespective of gravity
- mass
- the eclipsing of a heavenly body by the moon or by another planet
- occult
- the passage of an inferior planet across the sun's disk, or the passage of a star across the meridian
- transit
- planets that are the earth's size or smaller and about the same density of the earth
- terrestrial planets
- Jupiter's four largest moons, named after their discoverer
- Galilean moons
- a planet whose orbit is inside the earth's orbit
- inferior planet
- a reddish colored, oval-shaped area on Jupiter, possibly due to an atmospheric disturbance or storm
- Great Red Spot
- one of the four large outer planets
- Jovian planet
- the planets Jupiter, Saturn, Uranus, and Neptune, which have large gaseous atmospheres
- gas giants
- an oval-shaped figure having both ends alike; the characteristic shape of the orbits of planets, satellites, and periodic comets
- ellipse