One would think that the Big Bang Theory has been the greatest theory explaining how the universe came into being. The universe started approximately 13.8 billion years ago in a singularity, infinitely dense and hot, from which it exploded and thus was shaped into the cosmic world we view today. But what if the story doesn't start there? What if before the Big Bang, there was time?
Renowned physicist and communicator Brian Cox has
flung open the universe's possibilities with a hint that it might have indeed
preceded the Big Bang. According to Brian Cox, famous for making a science
career out of popularizing complex scientific ideas and now propounding
theories contrary to the accepted understanding of the Big Bang as the
"beginning of everything.".
Cox's remarks are based on modern theories of cosmology that propose that the universe is cyclic or even existed in some form or another before the Big Bang event. This would imply that the universe did not necessarily come from nothing; rather, it was transformed from an earlier state or phase of existence.
One of his discussions points out the possibility that what we believe was the Big Bang may have been just one stage in an altogether greater cosmic process. If this is so, then opens up a profound question: What happened before the Big Bang? Was there an earlier universe that collapsed and gave rise to our own?
The Cyclical Universe Theory
One of the most popular alternatives for the Big Bang Theory is the cyclical universe theory. The universe, under this theory, has been undergoing infinite cycles of expansion and contraction. This model shows a "Big Bang" beginning every cycle, after which it expands once more, such as what is happening now, until it eventually collapses upon itself into a singularity in a Big Crunch. This will lead to a new Big Bang and allow the cycle to begin once again.
This is one of those ideas that has roots in ancient days in many philosophical traditions but has only recently begun to be taken seriously in more modern scientific models, with the past few decades bringing much consideration of this hypothesis. There is certainly no "smoking gun" evidence for the cyclical universe, though some theorists, such as Sir Roger Penrose, have created models - such as CCC (Conformal Cyclic Cosmology) - that support this idea. Even Nobel laureate in physics Penrose asserts that the imprint of an earlier universe might even be observable in the cosmic microwave background radiation, the afterglow of the Big Bang.
Cox has intimated such ideas in his talks, suggesting it's quite possible that the universe could have had countless cycles of birth and rebirth and our Big Bang just one phase in a limitless series.
The Multiverse: Other Worlds Before and After?
The multiverse is another theory to which Cox has referred-the idea that many-or infinitely-many-universes exist. According to some multiverse models, our universe may be one bubble in a great cosmic ocean of universes, each having its own laws of physics.
In this sense, what we understand to be the Big Bang may simply be the moment when our universe "popped" into existence while other universes existed either alongside it or even before it. The implications are staggering in that our universe might not be unique after all and that time itself extends far more beyond the confines of the Big Bang.
Although these concepts are pure speculation and extremely speculative and therefore still decidedly theoretical, they do offer alternative visions of cosmic history that transcend the often-told singular origin tale as described in the traditional Big Bang Theory.
Evidence for a Pre-Big Bang Universe?
One of the biggest challenges in front of modern cosmology is to detect evidence for a universe before the Big Bang. In fact, the nature of the Big Bang itself means we can't directly see behind this boundary because the extreme conditions in the early universe would have deleted all information about earlier phases of the universe, were such to have existed.
However, indirect evidence are what scientists look for. The study of gravitational waves -ripples in space-time from violent cosmic events-most likely will someday provide the conditions before the Big Bang. Similarly, the very subtle patterns inside the CMB may harbor traces of an earlier cosmic phase.
Brian Cox has indicated that whereas all the modern knowledge about the universe's past is founded on the Big Bang theory, the presence of a universe before the Big Bang should not be dismissed without consideration. "The Big Bang is not necessarily the beginning," Cox once said, suggesting it may only be the source of our observable universe and not the entire cosmos.
Quantum Cosmology: Time and Space Beyond the Big Bang
This is another approach in trying to answer this question. Quantum cosmology is the effort to combine the principles of quantum mechanics with general relativity. Quantum theories of gravity, still under development, find that space and time could operate much more precariously or otherwise at energies and scales as big as those conceivable in the moment of the Big Bang.
Thus, some quantum cosmological models do not have, by any means explicitly stated, a "beginning" to time itself. Instead, the universe possibly was just in a quantum state before the Big Bang, and time should play by rules familiar to none of our classical understandings. According to Cox, these ideas might open up new ways of thought about the beginnings of the universe and even lead to the conclusion that the universe has no real beginning or end.
The Big Picture: What Does This Mean for Cosmology?
What Brian Cox is thinking about here-in a universe before the Big Bang-is part of a much larger cosmological trend to rethink the start of the universe. The standard Big Bang theory is very fantastically successful at explaining the observable universe, but it does have its own set of limitations. It says nothing, of course, of what would have happened before the singularity and can't say much about how the universe would end up.
Through ideas like cyclical universes, multiverses, and quantum cosmology, scientists like Cox will take us to the furthest frontiers of what we know and open new avenues of research in the deep history of the cosmos.
Conclusion: A New Cosmic Horizon
For Brian Cox, the idea that the universe existed before the Big Bang is more than a mere thought experiment. It challenges our understanding of the timeline of the universe, and what we call the Big Bang may only be half of a much greater story. The next great frontier of knowledge: cyclic universe theories, multiverse theories, or quantum cosmology.
As scientific tools and models continue to be advanced by man, discoveries of the future may unveil what came before the Big Bangand perhaps reveal that the universe has always been, but in forms we have yet to fully comprehend.
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