An interesting article in the new Scientific American discusses the possible implications of quantum gravity theory for Cosmology. In my limited understanding, quantum gravity theory was developed as an alternative to string theory in an attempt to reconcile Einsteins theory of general relativity with quantum theory–both of which are well confirmed but seem to conflict. One of the surprising predictions of quantum gravity theory is that space-time is atomistic–not continuous, as one would intuitively expect. In this recent article by Martin Bojwald, another consequence is explained: the universe did not begin with the Big Bang, but with a quantum driven contraction that resulted in an explosion–a big bounce. I can’t say I really completeluy understand it, of course, but the article proves interesting reading nonetheless. Check it out here.
One of the more interesting arguments for the existence of God claims that our universe is “finely tuned” so that life will emerge. In other words, with only slight variations in the physical constants the universe could not bear life, and the best way to explain the aptness of this universe is that the constants were set by an entity that wished for life to emerge. There are problems with the argument, of course, but the basic empirical premise is usually accepted–that the conditions under which a universe would bear life are rare. An interesting result to be published in The Journal of Cosmology and Astroparticle Physics, however, questions that.
Fred Adams at The University of Michigan in Ann Arbor maintains that the appearance of fine tuning is illusory. While it is perhaps true, Adams says, that if you fiddle with just a single characteristic of the universe it would no longer be apt for life, it does not follow that if you generated a host of settings randomly that the resulting universes would only rarely allow for life. When Adams ran a computer model of such a test, however, about a quarter of the universes included stars that result in some sort of life. Thus, even the empirical premise of the fine-tuning argument is substantially undermined.
Read more at The New Scientist.