Well there are perfectly reasonable theories such as in string theory where the big bang occurred as a collision of branes in a multidimensional already existing universe. Not that I understand it very well. But it's not a matter of something from nothing.
And the journey into scientific fantasy is complete. I thought physics was supposed to be about explaining the physical universe we inhabit? How is string theory tied to physical in any way? Multiverses and wormholes may be fun to imagine, they may even be more fun to experience with the aid of LSD but I don't think string theory adds much when far simpler phenomenon defy understanding.
Every culture needs it's creation myths though. Humans seem to have an inherent need for religiosity. We abhor uncertainty, so tell me a good story. It's interesting how frequently the blank piece of paper (nothing) upon which a point is created (God) and by extension of itself (a line -the holy spirit) terminates in a circle (matter, the universe and the son) occurs. So many variations on a theme.
Space, the sun, light, the earth - that must be how the universe was created.