Question

big bang theory define

Answer 1

My, you're a man of few words. :-)

http://map.gsfc.nasa.gov/universe/bb_theory.html

http://www.big-bang-theory.com/

Answer 2

The big bang theory states that the universe exploded in all directions from a single point which is otherwise known as singularity and it contained an enormous and incredibly concentrated amount of energy.At the instant of creation, the universe would have been unbelievably hot, with energy being converted into matter and antimatter.

Hope this helps.