Unit 1 Space

1. The portion of the electromagnetic spectrum that humans can see.
4. An imaginary line through an object around which it rotates.
6. A rounded object that orbits the Sun but has not cleared other objects from its orbital path.
10. High-energy electromagnetic radiation from the Sun that can damage living cells.
12. The force that attracts objects with mass toward one another.
13. Energy from the Sun that travels through space as electromagnetic radiation.
16. Three laws that describe how planets move around the Sun.
17. The spinning of an object around its own axis.
18. The region around an object where magnetic forces act; Earth's magnetic field helps deflect charged particles.
20. A tide with a smaller tidal range that occurs during the first- or third-quarter Moon.
21. A measurement of how stretched out or elliptical an orbit is.
23. A giant cloud of gas and dust from which our solar system formed.
24. A region of the atmosphere that absorbs much of the Sun's harmful ultraviolet radiation.
25. An icy object that orbits the Sun and can develop a glowing coma and tail when it gets close to the Sun.

2. A rocky, dense planet with a solid surface, such as Earth or Mars.
3. A gas in the atmosphere that absorbs and re-emits infrared radiation, helping warm Earth.
5. The Sun and all of the objects that orbit it, including planets, dwarf planets, asteroids, and comets.
7. The full range of types of electromagnetic radiation.
8. A large outer planet made mostly of gases such as hydrogen and helium.
9. A rocky or metallic object that orbits the Sun.
11. Electromagnetic radiation associated with heat.
14. The path an object follows as it travels around another object in space.
15. The center of mass around which two or more objects orbit each other.
19. The process in which smaller atomic nuclei combine to form a larger nucleus and release energy.
22. The movement of one object around another object.
23. A tide with a larger tidal range that occurs during a new or full Moon.