Why We Will Never Know What Happened Before the Big Bang

The Big Bang is a cosmological model in which the universe has been expanding for around 13.7 billion years, starting from a tremendously dense and hot state, thought to be the best model for the origin and evolution of the universe.

But what happened before the Big Bang? If something did happen, that caused the Universe to exist, we may never know what that was, according to a new theory of theoretical physicist Martin Bojowald of Pennsylvania State University in University Park.

He studied Einstein's theory of general relativity that explains the evolution of this Universe after the Big Bang, but breaks down at the point of origin, being unable to clarify what was there before the big event.

The scientist claims that we will never be able to discover what existed in the state before the explosion, because our experiments are not sensitive enough to completely reconstruct the original state, nor will they ever be.

Bojowald used a speculative theory that regards the Universe as pixilated into tiny atom-like units of space and time and came to the conclusion that reconstructing the initial state is impossible, because quantum fluctuations become smeared out after the Big Bang, thus impossible to read.

"If that is the case, then we're not able to determine the precise origin of the universe," says Bojowald. "It would always remain a philosophical scenario."

So far, the most widely accepted theory states that galaxies and clusters drift apart from each other as if propelled by an initial explosion of space and time, whose movements drag the cosmic masses. A logical thinking implies that, if this movement were to be reversed, all matter and energy would head for the same spot, the center of the blast.

The scientist imagined that if all this matter and energy gathered in one spot, they would become infinitely dense, ultrahot state. But a loop quantum gravity theory states that this may not be the case, and that spacetime is actually made of tiny pieces sort of like foam, that can only contain a finite amount of energy, thus producing a new model of the Big Bang.

According to Bojowald, the Universe existed before the Big Bang and collapsed under its own gravity in this prior phase and only then it began expanding, creating the universe we know.

"The model is still very simple," Bojowald says, but though no one can prove it to be wrong, it may question many more assumptions on the Universe, that we made over the years.