It's the central question posed to atheists around the world: "If there's no God, then how did the universe begin?"
Considering our universe has been expanding for billions of years, it's tough to accurately pinpoint why it was created, but Stephen Hawking has a theory and surprisingly it's not entirely dissimilar to religion-based faith.
The legendary physicist says that whatever happened before the Big Bang, the cataclysmic explosion of matter, exists outside our current understanding of time and space.
At the moment, we know how time and space works on Earth and in space to a certain degree, but those laws just simply either didn't exist before the bang or it existed in a way we're not familiar with yet.
Speaking to Neil deGrasse Tyson for a Popular Science special, Hawking said: "Nothing was around before the big, big bang. According to Einstein's General Theory of Relativity, space and time together form a space-time continuum or manifold, which is not flat, but curved by the matter and energy in it.
"Ordinary real time is replaced by imaginary time, which behaves like a fourth direction of space.
"In a Euclidian approach, the history of the universe in imaginary time is a four-dimensional curved surface like the surface of the Earth but with two more dimensions.
"The boundary condition of the universe is that it has no boundary.
"The Euclidian space-time is a closed surface without end like the surface of the Earth."
Professor Hawking then explains that the best way to picture this reality is by thinking of imaginary time and real time beginning at our Earth's South Pole. There is nothing south of the South Pole, in much the same way there was no time or space before time or space existed (in our understanding of it) before the Big Bang.
Ok, my head hurts just a little bit.
It's not an easy concept to take on, but you just have to have faith that space and time didn't exist as we know it on Earth before the Big Bang. The general theory is that the massive explosion happened 13.7 billion years ago and some agree that the universe is constantly expanding at a huge rate.
Interestingly, the Big Bang Theory does not comment on how the universe was created and instead focuses on 'the existence of energy, time, and space' of the Bang.
Again, that's a tough concept to wrap your head around and physicists say our understanding of the universe and the Big Bang is an evolving concept - so there could be more to learn in time to come.
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