Well big bang seemed to pop out of nowhere (and if it didn't, where did that magical fairy powder causing it come from?) What if God did it? Or what if God sees planets/solar systems/something even bigger as his real creation, and doesn't really care for small guys like us (or got bored of us since we haven't created anything he finds amusing yet?) Or what if dinosaurs were his original creation, but then he slipped into a black hole, and dinosaurs weren't under his watchful eye anymore? What if we are actually inside brain cell of a dog, who is inside brain cell of a hamster, who is... Man, thinking is fun.