There is something rather than nothing
The claim
Every fact about the physical world is contingent — could have been otherwise. Contingent things require explanation. The chain of explanation cannot regress forever, and it cannot be self-grounding. Something must exist whose nature is to exist.
The question 'why is there something rather than nothing?' is not childish; it is the most adult question. It cannot be dismissed by appeal to physics, because every physical answer presupposes the very thing being asked about — a contingent reality whose existence is not self-explaining. The only sufficient answer is a being whose existence is not contingent: necessary, self-explaining, pure act, ipsum esse subsistens. This is not 'God of the gaps.' It is what every serious metaphysical tradition — Vedantic, Neoplatonic, Thomist, Avicennan — has converged on by independent routes.
God is not a thing in the universe. God is the answer to why there is a universe.
Every philosophical tradition that has thought hard about being — Vedanta, Neoplatonism, Aquinas, Ibn Sina, Maimonides — has arrived at the same distinction: contingent being depends, necessary being does not. The latter is what the word 'God' has always named in serious theology. Not a powerful entity within the cosmos, but the very ground of there being a cosmos at all.
Modern atheism, by treating God as one more entity among entities — a celestial item that might or might not exist alongside galaxies and quarks — has been arguing against an idol it built itself. The classical God is not a candidate for the inventory. Asking whether God exists in that sense is like asking whether existence exists.
When Hawking writes that the universe can 'create itself from nothing' because of the laws of physics, he has changed the subject. Laws of physics are not nothing. A quantum vacuum is not nothing. Nothing is the absence of everything — including laws, fields, potentialities, and possibilities. The classical question is why there is any of that at all.
The only answer not in the same predicament as the question is: a being whose essence is to exist. Not a thing that happens to exist, but Existence itself, in which all contingent things participate. This is what Aquinas meant by ipsum esse subsistens — subsistent being itself.