Before the Big Bang?

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About 13.8 billion years ago, the Big Bang occurred — a very rapid expansion of the universe from a dense, hot, extremely compressed state.

Our models show that at the time of the Big Bang, the Universe was so strongly compressed that the gravity and density of matter in it were tending to infinity.

Then, for some reason, the universe began to expand very quickly, and the density of matter and temperature began to fall. Over time, atoms, the first stars and galaxies were formed, and finally on one ordinary planet, on the outskirts of an unremarkable galaxy, you and I appeared.

Thanks to physics, we have a pretty good idea of what happened

To be completely honest, science at the current stage cannot answer these questions. But we can make various assumptions.

According to one of the most famous astrophysicists of the 20th and 21st centuries, Stephen Hawking, there was simply nothing before the big bang. Hawking’s theory (in fact, not only him) is that the universe is limitless and neither time nor space simply did not exist before the Big Bang.

To better understand Hawking’s hypothesis, let’s imagine that we are moving back in time. As it moves backward, the universe will contract (just as it expands when moving forward). If we «rewind» time 13.8 billion years ago, then the universe that we will see will be compressed to the size of one atom. This state is called a singularity.

Inside the singularity, the laws of physics in the form in which they are known to us simply stop working. Likewise, the very concepts of space and time in a singularity are meaningless. We can say that before the universe began to expand, there was neither space nor time. At the same time, «rewinding» time back, we will asymptomatically approach the starting point, but we will never reach it.

Hawking’s hypothesis is one of many. There are many hypotheses explaining what happened before the big bang. Of interest is also the so-called «mirror hypothesis», which says that before the big bang there was a universe completely mirroring ours. Time flowed in it in the opposite direction, instead of matter there was antimatter and all processes proceeded in the opposite direction, etc.

Those. for example, if in our universe a chicken laid an egg, then they broke this egg and cooked an egg from it, then in the previous universe everything was the other way around — the eggs became liquid, then “gathered” into a whole egg, which “jumped” back into the chicken.

According to this hypothesis, that previous universe contracted until it reached the singularity, and after reaching the singularity, the Big Bang occurred, which gave rise to our universe.

It is unlikely that in the foreseeable future we will find out whether Stephen Hawking or the authors of the «mirror hypothesis» were right, or maybe the authors of one of many other hypotheses.

The Singularity is a fundamental barrier separating us from what came before it. Our understanding of the laws of nature is not yet sufficient to understand what is happening inside the singularity.

However, scientific progress does not stand still and I am sure that one day we will be able to lift the curtain over this secret of the universe.