A very interesting read-


The Big Bang theory proposes that the universe began as an extremely hot and dense dot only a few millimeters wide. It since grew over 13.7 billion years into the vast and cooler expanding cosmos that presently exists. An extension of the Big Bang model, inflation, poses that the universe initially expanded far faster than the speed of light and grew from a subatomic size to a golf-ball size almost instantaneously, shown in this diagram.