What happened before the Big Bang?

In many ways, it's strange to us humans that the Universe should be the age it is. The Universe - by definition, everything that physically exists - should either be infinite in age, or somehow tied to the lifespan of the human species, as it does in many mythologies. However, thanks to studies on the rate the Universe is expanding, and applying this knowledge in reverse, we know its age. Roughly 13.8 billion years ago, all we can observe on Earth, in our solar system, other galaxies and everything in between expanded out rapidly from an initial point much smaller than an atom, which we call the Big Bang.

The Big Bang model is our best explanation for why the cosmos appears as it does. Nevertheless, it's not able to answer some of the more challenging questions, including what - if anything - came before it? Despite how it might sound, this question isn't a philosophical one: it has potentially real, testable aspects. But to understand any of the possible answers, we must first understand the question itself, Kazinform quotes BBC News.

First of all, the language we use to describe what we know and don't know can sometimes be muddy. For instance, the Universe may be defined as all that exists in a physical sense, but we can only observe part of that. Nobody sensible thinks the observable Universe is all there is, though. Galaxies in every direction seem similar to each other; there's no evident special direction in space, meaning that the Universe doesn't have an edge (or a centre). In other words, if we were to instantaneously relocate to a galaxy far, far away, we'd see a cosmos very similar to the one we observe from Earth, and it would have an effective radius of 46 billion light-years. We can't see beyond that radius, wherever we're located.

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