The Big Bang Theory

2. The theory that the universe began as a single point and has been expanding ever since.
5. Accidental detection of Cosmic Microwave Background radiation in 1964.
7. The second lightest and second most abundant element in the universe, created shortly after the Big Bang.
8. The simplest and most abundant chemical element in the universe, formed first after the Big Bang.
9. The branch of science that deals with celestial objects, space, and the physical universe.
12. The capacity for doing work; in the early universe, all matter existed as pure energy.
13. The stretching of light waves toward the red end of the spectrum as an object moves away from the observer.
14. The full range of all types of electromagnetic radiation, from radio waves to gamma rays.
17. The small portion of the electromagnetic spectrum that human eyes can detect as colors.
18. The faint, uniform glow of microwave radiation filling the universe, considered the "afterglow" of the Big Bang.

1. The astronomer who discovered that galaxies are moving away from us, proving the universe is expanding.
3. A massive system of stars, stellar remnants, gas, dust, and dark matter bound together by gravity.
4. An astronomer who coined the term "Big Bang" as a way to mock the theory, despite preferring the Steady State model.
6. The shortening of light waves toward the blue end of the spectrum as an object moves closer to the observer.
10. All of space, time, matter, and energy.
11. The physicist who developed the General Theory of Relativity, which provided the mathematical foundation for an expanding universe.
15. Relentless pursuit of unexplained noise.
16. A scientific instrument used to break light into a spectrum to study its properties and movement.