We have already had the definitive answer posted to Free Republic. The universe exists inside a universe-sized star.
Three cosmic enigmas
The most intriguing fallout from this idea has to do with the strength of the vacuum energy inside the dark energy star. This energy is related to the star's size, and for a star as big as our universe the calculated vacuum energy inside its shell matches the value of dark energy seen in the universe today. "It's like we are living inside a giant dark energy star," Chapline says. There is, of course, no explanation yet for how a universe-sized star could come into being.
This is no more far fetched than the big bang's starting point.