1. _____ unit. The average distance between the Sun and the Earth (1,496,000,000 km).
7. The streak of light produced by a meteoroid burning as it enters Earth's atmosphere.
8. A relatively small body made of rock and ice with highly eccentric orbits around the Sun.
10. _____ motion. A planet's motion in the opposite direction across the sky.
11. The point in a planet's orbit where it is closest to the sun.
13. Extended volume of glowing that forms when a comet's nucleus is heated.
14. _____ planet. Relatively large, gaseous planets with ring systems and multiple moons (Jupiter, Saturn, Uranus, and Neptune).
16. A meteoroid which does not burn up in Earth's atmosphere and collides with Earth's surface.
17. Objects in space made up of solid particles which can form planets through collisions and mergers.
1. The point in a planet's orbit where it is farthest from the sun.
2. Rocky bodies left over from the formation of the solar system found in a belt between Mars and Jupiter.
3. _____ planet. Relatively small, rocky planets close to the Sun (Mercury, Venus, Earth, and Mars).
4. The wobble in the Earth's rotational axis.
5. Meteor _____. When the Earth's orbit intersects with a cometary orbit and comet particles burn up in the atmosphere.
6. The ratio of the distance between the foci and the length of major axis which defines a planet's elliptical orbit.
7. Small bits of solid interplanetary material travelling in space.
9. Cool, light-colored clouds that rise and flow rapidly in the atmospheres of gaseous giant planets.
12. The small, solid core of a comet.
15. Warm, dark-colored clouds that sink and flow rapidly in the atmospheres of gaseous giant planets.