The answer is that we don't know YET. And scientists are ok with that. We get raging hard-ons for the remaining mysteries in life, the fun of the chase, where others can't deal with that and turn to religion to get instant explanations.
"Science cannot explain..." is never a good argument against science.
We get paychecks because we don't know everything yet. When we have all the answers, there won't be scientists anymore.
Us philosophers make the precise same argument against the institution of science.
Not everything is accessible to the scientific method, and that is why we have other methods
such as hermeneutics, phenomenology, logic, and metaphoric literature as well as mysticism.
For example, just because I may witness a crime, does not mean that I can prove it
to a formal pedantic institution. That crime I still know to be real. But science that does not appreciate
its own limited philosophical context, will claim that the crime does not exist because it cannot be proven
to the institution.
It is true, that many people turn to dogmatic religion, often for instant explanations, but in recent centuries,
that is the role played by the institution of science, which itself often replaces empiricism and logic
with sheer belligerence and arguments from economics. Plenty of people get paid to to do all sorts
of things, and the more society progresses, the more people are paid redundantly.
The methods of hermeneutics, phenomenology, logic, metaphoric literature and especially mysticism
have all demonstrated that Gnosis of God is a real and lucid experience, which has motivated
the minds of the greatest thinkers, almost without exception.