Chapter 2 - Space

2. A piece of rock that breaks off an asteroid and travels through space
4. Tiny particles of solid materials floating around in the space between stars; the material from which new stars and planets are formed
9. A straight line passing from side to side through the center of a body or figure, especially a circle or sphere; a measurement of the line
12. Planets in our solar system that are beyond Mars and the asteroid belt and are farthest from the Sun: Jupiter, Saturn, Uranus, and Neptune
14. A trait that can help identify or classify something
17. A rock that revolves around the Sun
19. A force that pulls: 1. the planets toward the Sun; 2. objects toward the center of Earth; 3. physical objects of matter toward other physical objects having mass.
20. A large, round body that revolves around a star
21. A system of eight planets and the Sun, along with moons, asteroids, and comets, held together by gravity; our "cosmic neighborhood"
22. A group of billions of stars, the objects that orbit the stars, gas, and dust held together by gravity.

1. A meteoroid that reaches Earth's surface
3. Any object, natural or man-made, orbiting Earth or another planet
5. A nearly round body whose orbit crosses the orbit of other bodies
6. A curved path of an object around a star, a planet, or a moon
7. Galaxies that do not have any particular shape. The stars are randomly scattered.
8. Planets in our solar system that are closest to the Sun and before the asteroid belt: Mercury, Venus, Earth, and Mars
10. A natural satellite that travels around a planet
11. A meteoroid that burns up in Earth's atmosphere; also called a shooting star
13. A type of galaxy shaped like an ellipse or sphere with a smooth, nearly featureless appearance
15. A huge ball of extremely hot matter in space that gives off energy
16. A spiral galaxy made up of gas, dust, and stars where our solar system is located
18. A mixture of frozen gases, ice, dust, and rock that moves in an elliptical orbit around the Sun