What is the main evidence which supports the big bang theory?

1 Answer
Jun 15, 2017

The cosmic microwave background (CMB) is the main evidence which supports the big bang theory.

Explanation:

The early universe would have been filled with high energy photons. As it expanded, these photons cooled as the expansion of the universe caused them to get red shifted. This means that the current universe should be fairly uniformly filled with lower energy photons.

The CMB has been detected at a temperature of about #2.7^@#K. It can be detected in all directions. Since the discovery of the CMB in the 1960s the big bang theory became the dominant theory of the creation of the universe.