For the John Templeton Foundation, I wrote about how string theory might just unravel some of the the mystery of our finely-tuned cosmos.
In recent years physicists and astronomers have demonstrated that the laws and constants that govern the cosmos must be structured in highly precise ways in order for intelligent life to emerge. As a result, if the universe that we observe is the only one there is, its existence in a form that can support intelligent life seems incredibly improbable. But if there are a great many universes — a concept known as a multiverse — it is more likely that one would exist that has just the improbable features needed to sustain intelligent life. It’s an idea whose implications ripple out from physics into philosophy and theology.
String theory, a mathematical and conceptual framework that attempts to unify many disparate elements in fundamental physics, is thought to allow for if not require the existence of more than 10500 universes — a number sufficiently staggering to comprise a multiverse — but only if its constituent universes compose a so-called landscape of viable universes that resemble our own. One feature of this landscape would be a cosmological constant (the energy density of the vacuum of space) that is not negative. The observed universe has a cosmological constant that is small but positive.