WAS SPACE TIME CREATED BY BIG BANG OR DID IT EXIST BEFORE

 

What was there before the Big Bang? This is one of those questions that can make your head spin, especially if you try to answer it using only common sense. After all, how can something come from nothing? And how can time have a beginning if it is supposed to measure change?

Fortunately, or unfortunately depending on your perspective, common sense is not a reliable guide when it comes to the mysteries of the cosmos. To explore the origins of space and time, we need to use the tools of physics, which are often counter-intuitive and sometimes downright bizarre.

The standard story of the Big Bang goes something like this: about 13.8 billion years ago, the Universe was a tiny point of infinite density and temperature, called a singularity. Then, for some unknown reason, it exploded and started to expand rapidly, creating space and time as we know them. This expansion is still going on today, and can be observed by looking at the redshift of light from distant galaxies.

But this story has some problems. For one thing, it relies on the theory of general relativity, which describes gravity and the large-scale structure of the Universe, but breaks down at very small scales and high energies. To understand what happened at the singularity, we need a theory that can combine general relativity with quantum mechanics, which rules the microworld of particles and forces. Such a theory does not exist yet, although there are some candidates, such as string theory and loop quantum gravity.

Another issue is that the singularity itself is a mathematical anomaly that implies that something infinite came out of nothing. This does not make much sense physically, and suggests that there is something missing in our understanding of the initial conditions of the Universe.

Some physicists have proposed alternative scenarios that avoid the singularity and extend the history of space and time beyond the Big Bang. For example, some models based on string theory suggest that our Universe is one of many in a multiverse, and that it was created by the collision of two giant membranes called branes. Others suggest that our Universe is cyclical, and that it undergoes a series of big bangs and big crunches, with quantum fluctuations creating new universes out of old ones.

These scenarios imply that space and time existed before our Big Bang, but they may have been very different from what we experience now. For instance, some models suggest that before the Big Bang, there was a phase of quantum gravity, where space and time were subject to quantum fluctuations and had no definite structure. In this phase, there may have been no distinction between past and future, or between cause and effect.

These are all speculative ideas that have not been tested experimentally. They may turn out to be wrong or incomplete. But they show that physics does not rule out the possibility that space and time had a prehistory before our Big Bang. In fact, some physicists think that finding evidence for such a prehistory would be more satisfying than accepting a singularity as the ultimate origin of everything.

So what was there before the Big Bang? The answer may be: more space and time. But don't expect them to be familiar or friendly.