Why is there something and not nothing? Where did all the stuff we see come from? Did the Universe have a beginning? If not, why not?
Such are the questions facing cosmology today. One may say that philosophers have squabbled over these problems for milennia but may be for the first time we are on the cusp of an answer.
About a hundred years ago, Edwin Hubble looked through a telescope and saw galaxies moving away and concluded that the Universe is expanding. In the 1960s, Penzias and Wilson found empirical confirmation of an explosive beginning of the Universe, otherwise known as the Big Bang.
But what we would like to know is: what happened before the Big Bang?
That is a question that has remained unanswerable for many years and often cosmologists would refuse to even consider the possibility that there was any causality event before it. The Big bang was considered to have began from a singularity and it is impossible to predict anything beyond a singularity. What happened before the Big Bang? We do not know and very possibly cannot know.
Until a few years ago, that was the great cosmological consensus.
Until now.
BBC Horizon explors the many new ideas and opinions of a new group of scientists who are challenging the very idea that the Big Bang was any kind of a beginning. Horizon focuses on the Perimeter Institute – a radical group of physicists who are seeking to challenge the idea that the beginning of the Universe was from the Big Bang. In fact their work has gone a long way to make such radical notions into mainstream ideas.
One of the problems involving the Big Bang is the idea of inflation. According to the principles of Quantum Mechanics and General Relativity, the Big bang could not have turned the universe into what it is today. To solve that problem Andrei Linde came up with the idea of inflation- the rapid expansion of the Universe from a point to a size greater than the solar system within 10^(-34) seconds after the Big Bang.
The physicists of the Perimeter Institute, Neil Turok, Param Singh and Lee Smolin each have their own ideas. Turok thinks that a collision of membranes that each contained three dimensions and were separated by the time dimension gave rise to the Big Bang. Singh's idea is a little more radical: he proposes a Big Bounce- where the beginning of our universe comes from a previously collapsing universe. Nature, Singh argues, is cyclical- the end of one universe creates the beginning of another. Smolin argues that the origins of the universe may have preceded the Big Bang. In fact, he argues that the Universe has evolved into what it is today through natural selection. The universe is born through another universe procreating it.
Radical stuff, but even the once stalwarts of the Singularity idea are beginning to change their minds. Sir Roger Penrose, after a lifetime of asserting that we cannot know beyond the singularity is coming round to the idea that pre-singularity could have some credibility. He argues that since a very large universe would only contain photons and would be mass less, it could technically be equivalent to a very small universe. This could be the beginning of a Big bang for the next universe.
If that is not quirky enough, then we have Laura Mercini-Hougton arguing that the Universe is just one of many parallel universes. Using string theory, she could demonstrate that many inexplicable phenomena can only be explained in conjunction of a multiverse theory. Of all the views put forward, Mercini-Houghton's position is a little stronger since her theory requires very little assumptions.
In England, Bob Nichol is building one the world's largest radio telescopes that would be able to test the inflation theory of Linde. If the distribution of matter within the universe is random, then inflation would be proven correct. On the other hand, in Louisiana, Joe Giaimi is looking for gravity waves that would tell us about the aftermath of the Big Bang. These experimental approaches would shed light on the truth of the theoretical claims made by the cosmologists.
Whatever the truth may be, we can be sure that it would be overwhelmingly stranger and more wonderful than we ever thought possible.
What Happened Before the Big bang is the third episode of the 49th season of Horizon on the BBC.
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