The beginning of the Big Bang

There is a hundred billion galaxies with a hundred billion star systems in each one. Our universe seems vast and it could even be infinite, although we may never be able to prove it. Humans have pondered about the universal questions of how it started and how it is going to end for as long as our brain had the capability to do so and currently we have a very good idea as to the state of the universe up to the first second of its life and predictions of its demise. Most of those are based on the relatively recent discovery that the fabric that binds the universe is expanding. And not only that, is doing so at an ever increasing rate.

One of the common conceptions of the end of the universe is such where galaxies continue to distance themselves from other galaxies due to that expansion to the point where all visible light coming from stars in other galaxies travels slower than the rate of the universe expansion thus not allowing us, for example, to see them from our little blue planet. At some point, not even the closest stars will be noticeable and Earths' night sky will be indeed black as if looked from the brightest of one of our busiest cities. But it won't stop there, stars and planets will be torn apart and deconstructed like a modern cookery trick, until only particles of the subatomic type would remain.

Of course this will not happen in our lifetimes, potentially it won't happen even in the lifetime of our planet and arguably, humankind won't exist in any form whatsoever by that point. This puts our idea of time into perspective, the universe is young, just under 14 billion years, and it contains a lot of energy still to be exploited, we could say that it still needs to cool down. This brings me to the arrow of time, or entropy (the second law of thermodynamics), which undeniably drives all that exists in the universe to find a state of lower energy/temperature. And that is as much as we can say about time. Well, that's not true. We don't fully understand what time is, but we have proved how time behaves in certain extreme circumstances. For instance, objects travelling faster than others will have a different time frame. As in, time will be different for objects travelling at different speeds and the bigger the difference in speed, the more difference in time. This is noticeable and has been proven to be very useful as it is how our watches synchronize, all our watches, the time in your computer is calculated having that effect into account.

So if all of this is true, and the universe will just dissipate given sufficient time, how did it start? Think about it, if the arrow of time tends to make all matter disappear, how did it come to be in a single point, all concentrated and full of potential energy and mass, as the Big Bang Theory suggests and we know that reversing the expansion of the universe, it must be true. All mass and energy was in a single point in space. We may not know how that happened, or how that concentrated point of energy and mass behaved, we don't know its properties and what is more, we have no idea of what happened before the big bang. One of the attempts of current scientists to explain it is based on one of the most curious quantum behaviors observed in subatomic particles and entropy. Which in essence says that there is a slight chance that all particles in the universe may rearrange themselves and appear spontaneously in a single point. A relatively old hypothesis proposes that the universe may stop expanding and start contracting. In both cases we are unable to prove it right or wrong and neither of them sound even plausible.

So let's imagine an alternate explanation. what if our entire universe was inside a black hole? This is not a new idea but perhaps requires new physics to explain how that would be possible and we aren't there yet. So that's why we need to imagine it. Consider a black hole and what we know about them, which isn't much. Everything that comes close enough gets pulled by its intense gravitational pull and disappears. We know that black holes emit radiation and perhaps that radiation is a sign of the same effect that we observe everywhere else, that black holes are losing energy and will one day dissipate along with all the other matter in the universe. However there is so much we do not know. We don't know how particles behave inside the black hole, the same way we know nothing about the singularity that exploded in the big bang theory. Two singularities we don't know much about. Coincidence? Perhaps not.

The intense gravitational pull of black holes don't let light or any other mass or energy come out, which means that objects falling into it must be travelling at the speed of light, or in other words, they transform into energy instantly after crossing the event horizon. This again reminds us of the singularity that gave birth to our universe. The second idea is related to time. Objects travelling at the speed of light, experience local time as normal, however from an observer perspective time passes much faster. Think of it this way, if you were travelling around the Earth at speeds 80% the speed of light for a few years (the time that you travel from your perspective) when you came back down to the surface you will notice everyone you know is either much older than just a few years or maybe even dead. Nice! As a result, for us, the energy and mass inside of black holes are in an apparent eternal time freeze. We may never notice any changes inside a black hole or observe any phenomena because they happen so slowly that the age of our universe is not enough to see them. However black holes may continue to absorb mass and energy for a long time, probably even after the universe has decayed into just particles.

In this thought experiment we are talking about a black hole growing in mass or energy for longer than we can even imagine. Perhaps billions of universe lifetimes. Presumably enough time for a black hole to reach its point of no return, where no more energy can be compacted any more and a massive explosion will release all that mass and energy, sounds familiar? I would argue this addition to the Big Bang Theory is more likely than all the particles of the universe rearranging themselves into a single point since they would be so far apart, and the energy required would be so big, it sounds more plausible if that was a process that happened gradually. Despite the statistical possibility of it happening.

So there you have it. Our universe started as a black hole, inside a universe that started as a black hole and so on ad infinitum. Next question, where did all the matter and energy come from? How did it get here?