How did the molecules that caused the big bang come about?

Answer

I’ve never heard before that the Big Bang was caused by molecules. It has also been taken out of thin air. Molecules require atoms, and atoms were only created after the big bang.

We all struggle with the fact that on the one hand it’s pretty obvious that there was a ‘big bang’, and on the other hand we can’t really understand that big bang. We derive this ‘being clear’ from various arguments: space expands, so it used to be smaller, and has been reduced far enough in time to a minimal extent; we find that the resulting time scale agrees well with the age of the oldest objects in the universe; theories about the early universe state that the universe must still today be filled with a kind of cosmic ‘background radiation’, which we do observe; the extent to which the various elements of Mendeleev’s table occur in the universe agrees very well with our models of the Big Bang and of stars.

It is therefore quite certain that it was once very close together. But as we get closer to the beginning, our understanding becomes less and less certain. This is because we are confronted with ever greater energies, energies that we cannot mimic, and for which we do not have experimentally verified physics. So it has to be done with models that may be plausible, but which are difficult to test experimentally. Nevertheless, the search for a better understanding of the big bang is useful: it can help us to distinguish the essential from the incidental in our questioning. But at the same time, that quest may never be finished, a new why question always pops up. If we could ever find a consistent theory of how “something can come into existence out of nothing,” the next question is what that theory, in turn, rests on.