One of the supposed "deep" questions that (we're told) only religion can answer is the question, Why is there Something rather than Nothing? Science might be able to explain the workings of the universe, but it can't explain why the universe exists, or so the philosophers and priests say.
But why shouldn't the universe exist? It's been assumed at least as far back as Leibniz that "nothing" is simpler than "something", that nothingness "just happens" but to get the material universe you need to do a bit more work.
But that's just an assumption. Why shouldn't there be Something rather than Nothing? Perhaps the best answer to the question is "Well, why not?". Maybe there can't fail to be Something. There's Something because there cannot fail to be Something.
There's no reason to prefer the assumption that nothingness is simpler than something. We have no experience of nothingness. Nothingness is not the same as a lack of some particular object. There is nowhere we can go or to point to and say "Look, there's nothing. It needs no explanation. Now, how did something form from it?"
We once believed that "Nature abhors a vacuum". Although we now know that it is relatively easy to remove all the matter from a volume of space, indeed most of the universe is a low-grade vacuum, we could easily revise the old saying as "Nature abhors Nothingness". Everywhere you go, there are electromagnetic and gravitational fields -- and even if you could shield a volume of space from them (how???) you can't avoid having space and time itself. Getting space-time isn't hard, it's already there. Getting the nothingness in the first place is hard.
It isn't as if nothingness floated around in space for millions of years before suddenly exploding into something in the Big Bang. Time and space themselves began in the Big Bang. There was no "before the Big Bang". The very question "what happened before the Big Bang?" is meaningless, like "what's north of the North Pole?".
We shouldn't make the mistake of assuming that Something needed to be somehow created from Nothingness. Maybe the natural state of being is that Something is easy and Nothingness would be the hard thing to explain -- except that naturally if there was Nothing we wouldn't be there to ask why there was Nothing rather than Something.
(We wouldn't be where?)
There is no justification for the priests' assumption that only God or Gods can explain why there is Something rather than Nothing. Consider: suppose we said that God created the universe from Nothing. But hang on a second -- we had just agreed that Nothing existed. How does God fit into Nothing? Isn't God Something? If you're going to say that God existed, why not just accept that the universe existed and be done with it?
"How do you get Something from Nothing?"
"Well, start with Nothing, then add one God that you had prepared earlier, and voilà! you have Something."
Cosmic Variance has more:
Ultimately, the problem is that the question — “Why is there something rather than nothing?” — doesn’t make any sense. What kind of answer could possibly count as satisfying? What could a claim like “The most natural universe is one that doesn’t exist” possibly mean? As often happens, we are led astray by imagining that we can apply the kinds of language we use in talking about contingent pieces of the world around us to the universe as a whole. It makes sense to ask why this blog exists, rather than some other blog; but there is no external vantage point from which we can compare the relatively likelihood of different modes of existence for the universe.
So the universe exists, and we know of no good reason to be surprised by that fact.
If you spend some time reading the Stanford Encyclopedia of Philosophy article, you may notice the knots philosophers have tied themselves into by confusing privatives like "holes" with actual things. Our human penchant for reification, as useful as it can be, also confuses us.