I can't imagine what a scientific explanation would look like, or how we would know that it was correct, but I also have no reason (other than that) to think we won't someday have one.
Everything we know about the physical world is derived from the contents of consciousness; completing the loop and explaining consciousness in terms of the physical world would be cool. :) But I can't sketch out how it would work.
(Where by "consciousness" I mean subjective experience, not easy stuff that can be straightforwardly measured objectively.)