Through The Looking-Glass

Since the Big Bang was first proposed as a cosmological model for our universe — a model that has since been accepted with confidence by the astrophysical community — it has been assumed that it might well be impossible in principle to say anything about the state of the world prior to the initial singularity. But according to a story in yesterday’s newlsetter, a promising theory known as Simplified Loop Quantum Gravity now suggests that the previous iteration may have left readable traces in our present environment, and that this relic information indicates that the previous go-round was a time-reversed mirror image of our own.

One of the arguments that sometimes draws sensible people into theistic beliefs is the apparent fine-tuning of the physical constants of Nature: if the settings of these various “dials” were off even minutely, ordinary matter, and therefore life, could not exist. The response known as the “weak anthropological principle” points out that were they not so, we wouldn’t be here to note the fact, and therefore if there is an infinite or widely diverse assortment of universes out there (a situation usually referred to as the “Multiverse”), it is only in those universes that meet the necessary conditions that intelligent life will arise. Such lifeforms will then look around and marvel at the apparently purposeful fine-tuning of their world, as we are now.

For such a scenario to correspond to truth, it is necessary that there be some arrangement whereby there can be a diversity of universes. One suggestion has been that universes go from Big Bang to expansion to collapse to Big Bang in an endless sequence, and that in each “bounce” the laws of Nature may vary (a scenario that would seem less likely in light of this new model). Another possibility is that the Multiverse consists of a “horizontal” or “parallel” assortment of Universes that exhibit the necessary variation.

A particularly intriguing idea was put forward by the astrophysicist Lee Smolin, who suggested that if black-hole singularities are the generators of new Big Bangs, and thereby new universes, and the child universes tend generally to preserve the natural laws of the parent, then we would have replication with variation, which is of course all you need for a Darwinian process to get underway. In other words, universes whose laws favor the formation of black holes would tend to make more copies of themselves. If it happens that the same conditions that favor black-hole creation are also those that favor life, then life-friendly universes would have a selective advantage. This is all enormously speculative, of course, but it is a remarakbly clever idea. Smolin developed this notion of “cosmological natural selection” in his 1999 book The Life of the Cosmos.

You can read the Physorg article here.

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