ARE PARALLEL UNIVERSES REAL??
Dan KOLITIZ: Perhaps there is a world, in a distant galaxy, where I am being paid $6,000 a word to write this introduction. In that world, I’d almost certainly feel compelled to make it as long as possible — to ruminate at length on the philosophical implications of the multiverse, perhaps even write detailed breakdowns of the cultures/landscapes of five or six of them, tracking my divergent selves across multiple cosmic plains. That world, tragically, is not this world. But is it, or something like it, out there somewhere? Is the multiverse made up, or does it have some scientific merit? For this week’s Giz Asks, we reached out to a number of experts to find out.
My take: One version of parallel universes that cosmologists consider is the so-called ‘Multiverse,’ which is a consequence of the dominant theory of cosmic genesis known as inflation. Inflation explains why the Universe has the properties it’s observed to have — the absence of large-scale spatial curvature (also called ‘the flatness problem’), the pattern of fluctuations in the Cosmic Microwave Background, and the origin of vast structures such as galaxy clusters. The major lacuna of inflation theory is a way for inflation’s energy source — the inflaton — to begin inflating and produce the properties of a universe which has observers such as us. The incredible degree of fine-tuning required for life suggests, to some, the Multiverse paradigm wherein all values of the inflaton’s energy are realized…somewhere, in a potentially infinite number of disconnected, parallel Universes.
Physicist Max Tegmark estimates that a volume of spacetime with properties identical to our observable universe — our ‘nearest neighbor’ universe — could be about 10^10115 meters away from us, which is a number so incomprehensibly large it cannot be written in decimal form in a human lifetime, let alone detected with any conceivable technology cosmologists have access to. For now, the question of the reality is purely academic. But if inflationary B-mode polarization of the Cosmic Microwave Background is convincingly detected, it will give credence to the inflationary paradigm, which will indirectly bolster the case for the Multiverse’s version of parallel universes.