The Big Bang Theory

2. the lightest, simplest, and most abundant chemical element in the universe
4. The branch of science that deals with celestial objects, space, and the physical universe as a whole.
5. He provided the first observational evidence for the Big Bang theory by discovering in 1929 that the universe is expanding
10. also accidentally discovered the Cosmic Microwave Background
13. he faint, uniform, and pervasive remnant radiation left over from the Big Bang, dating back to approximately 380,000 years after the universe's origin
16. A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
17. a colorless, odorless, tasteless, and non-toxic inert noble gas
18. Theory of relativity (1916) provided the mathematical foundation for the Big Bang theory by suggesting the universe must be expanding

1. accidentally discovered the Cosmic Microwave Background
3. famously coined the term "Big Bang" during a 1949 BBC radio broadcast to mock the theory
6. the entire, continuous range of all possible frequencies and wavelengths of electromagnetic radiation
7. all existing matter and space considered as a whole; the cosmos.
8. the narrow segment of the electromagnetic spectrum detectable by the human eye
9. the prevailing cosmological model explaining that the universe began approximately 13.8 billion years ago from an extremely hot, dense singularity
11. an apparatus for photographing or otherwise recording spectra.
12. the quantitative property that must be transferred to an object to perform work on, or to heat, that object
14. the increase in wavelength
15. the decrease in wavelength