Approximately 10 billion years ago, a massive blast “allowed all the universe's known matter and energy...to spring from some ancient...type of energy.*” The theory states that in much less than a second, the universe expanded from the size of a dime to astronomical scope. Over the next few billion years, the universe continued to grow at a much slower pace. About 5.4 billion years after the big bang, the Earth was formed.

What is the Big Bang?

*nationalgeographic.com