Physic and Astronomy wrap-up

4. Everything that physically exists.
7. Electromagnetic radiation of a wavelength that is visible to the human eye.
8. A negatively-charged sub-atomic particle.
10. The basic building block of all normal matter.
12. A state of matter consisting of a collection of particles without a definite shape or volume.
14. Independent directions in space-time.
16. A nuclear reaction in which the nucleus of an atom splits into smaller parts.
18. A Convenient unit for measuring the large distances in the universe.
19. Newtons ___ Law of Motion: Objects at rest tend to stay at rest.
21. A massive, luminous ball of gas or plasma, held together by its own gravity is called a ___.

1. My teacher calls himself.
2. The idea by Galileo Galilei in 1632 and also known as the principle of invariance.
3. A large accumulation of antiparticles.
5. _____ laws of motion The three physical laws.
6. High speed, energetic particles originating from space that impinge on Earth's atmosphere.
9. The mass of an object divided by its volume.
11. The natural tendency of objects to resist changes in their state of motion.
13. The lowest temperature possible.
15. An atom or molecule that has been stripped of one or more of its orbiting electrons.
17. A type of elementary particle which is the major constituent of matter.
20. A measure of the amount of matter in a body is _____.