Chapter 4 Vocabulary

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Across
  1. 4. The solid part of the head of a comet
  2. 6. A regular oval shape
  3. 7. Having or representing the earth as the center, as in former astronomical systems
  4. 9. An object _____ when it spins around a central axis
  5. 10. Having or representing the sun as the center, as in the accepted astronomical model of the solar system
  6. 12. the earth's atmosphere, becoming incandescent as a result of friction and appearing as a streak of light
  7. 14. Sun, Heliocentric
  8. 15. Sphere,Photosphere
  9. 16. A celestial body that orbits the sun, has sufficient mass to assume nearly a round shape, clears out dust and debris from the neighborhood around its orbit, and is not a satellite of another planet.
  10. 17. Often called the inner planets
  11. 19. A celestial object consisting of a nucleus of ice and dust and, when near the sun, a “tail” of gas and dust particles pointing away from the sun
  12. 20. Color, Chromosphere
  13. 21. A celestial body resembling a small planet but lacking certain technical criteria that are required for it to be classed as such.
  14. 22. A small body moving in the solar system that would become a meteor if it entered the earth's atmosphere
  15. 23. Stretches more than 1,000 times the distance between the sun and neptune
  16. 24. The collection of planets and their moons in orbit around a sun, together with smaller bodies such as asteroids, meteoroids, and comets.
  17. 28. One of many small solid celestial bodies thought to have existed at an early stage in the development of the solar system
  18. 29. Force that attracts all objects together
  19. 30. A thin disk of small particles of ice and rock
Down
  1. 1. A region of the solar system beyond the orbit of Neptune, believed to contain many comets, asteroids, and other small bodies made largely of ice
  2. 2. A meteor that survives its passage through the earth's atmosphere such that part of it strikes the ground.
  3. 3. The trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface
  4. 5. A large, bowl-shaped cavity in the ground or on the surface of a planet or the moon caused by an explosion, the impact of a meteorite, etc.
  5. 8. The area between the orbits of Mars and Jupiter where a whole bunch of asteroids orbit.
  6. 11. A diffuse cloud of gas and dust surrounding the nucleus of a comet
  7. 13. motion of one object round another
  8. 18. A unit of measurement equal to 149.6 million kilometers, the mean distance from the center of the earth to the center of the sun.
  9. 25. Hardened rock formed from lava flows on the moon
  10. 26. A large planet of relatively low density consisting predominantly of hydrogen and helium, such as Jupiter, Saturn, Uranus, or Neptune
  11. 27. A small rocky body orbiting the sun