Flashcards: Science Chapter 9
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Created by:
titansforever on September 19, 2011
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Terms | Definitions |
|---|---|
 astronomical unit | The average distance between the sun and the Earth. |
| terrestrial planet | on of the highly dense planets nearest to the sun; Mercury, Venus, Mars, and Earth |
| Jovian planet | any of the four outermost planets in the solar system; much larger than Earth and gaseous in nature (like Jupiter) |
| prograde rotation | The counterclockwise spin of a planet or moon as seen from above the planets North Pole; rotation in the same direction as the sun's direction. |
| retrograde rotation | The clockwise spin of a planet or moon as seen from above the planets North Pole. |
| gas giant | A planet that has deep, massive atmosphere, such as Jupiter, Saturn, Uranus, or Neptune. |
| satellite | A natural or artificial body that revolves around a planet. |
| dwarf planet | Any object that orbits the sun, is round because of its own gravity, but has not cleared its orbital path. |
| comet | A small body of ice, rock, and cosmic dust that follows and elliptical orbit around the sun and that gives off gas and dust in the form of a tail as it passes close to the sun. |
| asteroid | A small, rocky object that orbits the sun, usually in a band between the orbits of Mars and Jupiter. |
| asteroid belt | The region of the solar system that is between the orbits of Mars and Jupiter and in which most asteroids orbit |
| meteor | A bright streak of light that results when a meteoroid burns up in the Earth's atmosphere. |
| meteoroid | A relatively small, rocky body that travels through space. |
| meteorite | A meteoroid that reaches the Earth's surface without burning up completely. |
| light-year | The distance that light travels in one year; about 9.46 trillion kilometers. |