Give a brief description of the Big Bang and describe its link to cosmic microwave background radiation.

The Big Bang is the leading theory on the creation of the universe. It states that all mass and energy were concentrated at a single point before a large explosion occurred, signalling the start of time. In the universe, matter dominated over antimatter. When these two came into contact they annihilated and produced gamma waves until there was no antimatter left.The Big Bang caused a rapid expansion of the universe which in turn cooled it. The gamma waves produced by the matter-antimatter annihilation were therefore cooled to the microwave region of the electromagnetic spectrum (at around 3K). This is what is known as the cosmic microwave background radiation and it saturates the universe. As it is detected in every direction it implies the universe is isotropic and homogeneous which falls in line with the Big Bang theory.