Have we found the universe that existed before the Big Bang? The current cosmological consensus is that the universe began 13.7 billion years ago with the Big Bang. But a legendary physicist says he's found the first evidence of an eternal, cyclic cosmos. The Big Bang model holds that everything that now comprises the universe was once concentrated in a single point of near-infinite density. Before this singularity exploded and the universe began, there was absolutely nothing - indeed, it's not clear whether one can even use the term "before" in reference to a pre-Big-Bang cosmos, as time itself may...