As the keeper of a Charles Darwin website, I receive occasional emails from fundamentalist Christian loonies, who inform me that evolution is "only a theory", but who don't seem to realise that the first chapter of the Book of Genesis is only a creation myth.
When it comes to explaining reality, give me a theory over a creation myth any day.
Curiously, these loonies never attempt to explain what makes them think the Genesis creation myth is so much better than any of the hundreds of others they could have chosen. I don't bother arguing with them any more, and simply refer them to my standard response.
Employing divine intervention to explain how the universe came about clearly explains nothing, in that it begs the obvious follow-up question, "So where did God come from, then?" Adhering to Occam's Razor (Pluralitas non est ponenda sine necessitate, in case you were wondering), we make fewer assumptions if we claim that the universe was created out of (and by) nothing, than claiming that God was created out of (and by) nothing and then took it into His divine head to create the universe.
The latest scientific thinking is far simpler:
New Scientist: How 3D space survived the great destruction
Why do we live in a space with only three dimensions? Because, at some time in the past, all the universes with four or more dimensions collided and destroyed each other, while our 3D space survived by slipping between collisions. Or at least, that is what a new theory claims.
Easy-peasy, you see?
It sounds like a tall tale. Can't we accept that our universe has three space dimensions and that's that? Not if you believe in string theory—physicists' best bet for a fundamental description of all particles and forces—which needs nine spatial dimensions.
Nine dimensions. Got that?
In one interpretation of string theory, called braneworld, those extra dimensions are large, perhaps even infinite, and our universe is just a 3D membrane drifting in a higher-dimensional space. However, that does not explain why our "brane" has three rather than, say, four or seven dimensions.
Now a team led by Ruth Durrer of the University of Geneva in Switzerland has an explanation. The idea is that the cosmos once included branes with up to eight dimensions, floating about at random in nine-dimensional space. In their model, this 9D space has the form of a torus, or doughnut, with each dimension circling back on itself (www.arxiv.org/hep-th/0501163).
Mmmm! Nine-dimensional doughnuts!