Big Bang theory
The Big Bang is a theory that the universe was once in a very hot, dense state and then expanded outwards, approximately 14 billion years ago. It is the most popular theory about the origin of the universe, widely accepted in the scientific community. It was first proposed by Georges-Henri Lemaitre. More evidence for the Big Bang was found by Edwin Hubble and Bell Labs. Later George Gamow predicted that the Big Bang would leave an observable microwave background radiation. This radiation was subsequently discovered and found to be close to that predicted by Gamow (Gamow predicted a background radiation level equivalent to a 3 K black body object, and the observed level is that of a 2.725 K body).
It is interesting to note that the Genesis account of creation, "In the beginning, God created the heavens and the earth, and the earth was without form and void, and darkness was upon the face of the deep; and God said, "let there be light," and lo, there was light," could be a literal description of the big bang as understood by current cosmologists; in this way, the big bang theory can be seen as a validation of biblical text..
Young-Earth creationists hotly contest the Big Bang Theory because they believe that the Bible proves that the Earth is far younger than 14 billion years.