The Big Bang is the beginning of everything -- a singularity which expanded into what we know as the universe.

    13.7 billion years ago, the universe changed from a dense singularity to what we see today. To further prove this, scientists have been observing light and radiation left over from this event. The universe doubled in size around 90 times in the first "hundreth of a billionth of a trillionth of a trillionth of a second" according to space.com. As the tiny universe began to expand, it cooled down, leading to the formation of matter. Then, light chemical elements formed in the first 3 minutes. The rest followed after.