: Key proofs include the Cosmic Microwave Background (CMB) and the observed expansion of space.
Use these quotes and phrases for images of Sheldon, Leonard, Penny, and the rest of the gang. : "Bazinga!" — Sheldon Cooper's trademark joke signal. The Big Bang Theory image
: The universe expanded from an extremely small, hot, and dense state and has been cooling ever since. : Key proofs include the Cosmic Microwave Background
: Most physicists believe the universe was born approximately 13.8 billion years ago . The Big Bang Theory image
What Is the Big Bang? | NASA Space Place – NASA Science for Kids
: The idea that the universe began as a single point, then expanded and stretched to its current size.