Ch. 11-14 Key Terms

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Across
  1. 4. a small piece of solid matter that enters Earth’s atmosphere and burns up, popularly called a shooting star because it is seen as a small flash of light
  2. 5. a portion of a meteor that survives passage through the atmosphere and strikes the ground
  3. 6. a tail consisting of two parts: the dust tail is made of dust loosened by the sublimation of ice in a comet that is then pushed by photons from the Sun into a curved stream; the ion tail is a stream of ionized particles evaporated from a comet and then swept away from the Sun by the solar wind
  4. 8. chemical changes caused by electromagnetic radiation
  5. 9. a type of differentiated meteorite that is a blend of nickel-iron and silicate materials
  6. 12. an Earth-approaching asteroid, one whose orbit could bring it on a collision course with our planet
  7. 14. the radiation emitted by charged particles being accelerated in magnetic fields and moving at speeds near that of light
  8. 17. the solid chunk of ice and dust in the head of a comet
  9. 18. the region of the solar system between the orbits of Mars and Jupiter in which most asteroids are located; the main belt, where the orbits are generally the most stable, extends from 2.2 to 3.3 AU from the Sun
  10. 20. the heating of a planet or moon’s interior by variable tidal forces caused by changing gravitational pull from a nearby planet or moon
  11. 21. many meteors appearing to radiate from one point in the sky; produced when Earth passes through a cometary dust stream
Down
  1. 1. a planet orbiting a star other than our Sun
  2. 2. a region of space beyond Neptune that is dynamically stable (like the asteroid belt); the source region for most short-period comets
  3. 3. a small body of icy and dusty matter that revolves about the Sun; when a comet comes near the Sun, some of its material vaporizes, forming a large head of tenuous gas and often a tail
  4. 7. the gradual accumulation of mass, as by a planet forming from colliding particles in the solar nebula
  5. 10. an orbital condition in which one object is subject to periodic gravitational perturbations by another, most commonly arising when two objects orbiting a third have periods of revolution that are simple multiples or fractions of each other
  6. 11. a comet or asteroid whose path intersects the orbit of Earth
  7. 13. a meteorite composed mostly of stony material, either primitive or differentiated
  8. 15. a stony or metallic object orbiting the Sun that is smaller than a major planet but that shows no evidence of an atmosphere or of other types of activity associated with comets
  9. 16. a meteorite composed primarily of iron and nickel
  10. 19. the large spherical region around the Sun from which most “new” comets come; a reservoir of objects with aphelia at about 50,000 AU