Heard a fellow claim a little while back the period in which the Big Bang occurred is a placeholder for our lack in understanding with respect to the laws of physics and such.
The only actual explanation that is as quaint as the idea of God, is the whole computer simulation theory(evidence being the unaccounted for dark matter/energy and such). Only problem with that theory, is we're back to square-one almost, with no way of proving or disproving it until we can exit the system and get a third person view of it from the outside(sort of like a religion of sorts now that has proponents saying "don't bother, since you can't leave a simulation").
It also doesn't make sense to propose theories more complex, as everything we've observed in our reality starts with simplicity, and expands unto complexity. Even if it were true that we are in a simulation, it doesn't do anything to expanding our understanding since we can't prove it, or disprove it.. The only time it would make sense to start talking about it seriously, is if everything in the simulation was fully understood. Which as we can see, we don't have a full grasp of our reality.