Unit 8 Lessons 4-6

4. a meteoroid that reaches Earth’s surface without burning up completely
6. one of the hundreds or thousands of small bodies that orbit that s sun in a flat belt beyond Neptune’s orbit; also includes dwarf planets located in the Kuiper Belt
7. small body that gives off gas and dust as it passes close to the sun: typical comet moves in an elliptical orbit around that sun and is made of dust frozen gases
9. the average distance between Earth and the Sun: approximately 150 million kilometers
11. the four largest moons of Jupiter: Lo, Europa, Ganymede and Calisto
13. a disk of matter that encircles a planet that consists of numerous particles in orbit which range in size from dust grains up to objects tens of meters across
14. a celestial body that orbits the sun, is round because of its own gravity, but has not cleared its orbital path

1. a small rocky object that orbits the sun; most asteroids are located in a band between the orbits of Mars and Jupiter
2. one of the highly dense planets nearest to the sun; Mercury, Venus, Mars and Earth
3. a spherical region that surrounds the solar system, that extends from the Kuiper Belt to almost halfway to the nearest star and that contains billions of comets
5. a bright streak of light that results when a meteoroid burns up in Earth’s atmosphere
8. a relatively small rocky body that travels through space
10. a region of the solar system that starts just beyond the orbit of Neptune and that contains dwarf planets and other small bodies made mostly of ice
12. a planet that has a deep, massive atmosphere, such a Jupiter, Saturn, Uranus or Neptune