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Chapter 28.1-4
Formation of the Solar System
| Question | Answer |
|---|---|
| planetismal | space object built of solid paricles that can form planets through collisions and mergers |
| retrograde motion | a planets apparent backward movement in the sky |
| ellipse | an oval that is centered on two points called foci; the shape of planets orbits |
| astronomical unit | the average distance between the sun and earth (93 million miles) 1.496x10^8 |
| eccentricity | ratio of the distance between the foci to the length of the major axis; defines the shape of a planets elliptical orbit |
| terrestrial planets | one of the rocky surfacedrelatively small, denser inner planets closet to the sun- Mercury, Venus, Earth and Mars |
| scarps | cliff on Mercury; similar to those on earth but much higher |
| gas giant planets | large, gaseous planet that is very cold at is surface; has ring systems, many moons, lacks a solid surfaces- Jupiter, Saturn, Uranus and Neptune |
| liquid metallic hydrogen | fomr of hydrogen with both liquid and metallic properties that exists as a layer in the jovian atmosphere |
| belts | low, warm, dark colored cloud that sinks and flows rapidly in the Jovian atmosphere |
| zones | high. cool light colored cloud that rises and flows rapidly in the Jovian atmosphere |
| dwarf planet | and object that, due to its own gravity, is spherical in shape, orbits the sun, is not a satellite, and has not cleared the area of its orbit of smaller debris |
| meteoroid | peice of interplanetary material that falls toward earth and enters its atmosphere |
| meteor | streak of light produced when a meteriod falls toward earth and burns up in the earths atmosphere |
| meteorite | a small fragment of an orbiting body that has fallen to earth, generating heat; does not completely burn up in the Earth'satmosphere and strikes the Earth's surface, sometimes causing an impact crater |
| Kuiper belt | small solar system bodies that are mostly rock and ice, lies outside the orbit of Neptune, 30 to 50 AU from the Sun, most probably formed in this region |
| comets | small, eccentrically orbiting body made of rock and ice which have one or more tails that point away from the sun |
| meteor shower | occurs when earth intersects a cometary orbit and comet particles burn up as they enter Earth's upper atmosphere |