Cutting Edge

Dr Gregory Farrelly FAITH Magazine January-February 2013

The Big Bounce -Doing Physics and Doing Theology

Pope Benedict, speaking to a conference of the Pontifical Academy of Sciences on 8 November, said:
"The universe is not chaos or the result of chaos. Rather, it appears ever more clearly as an ordered complexity".
We should stop here and remind ourselves that this grasp of ordered complexity is not some intellectual
framework imposed as a result of faith but a result of the application of scientific deduction and induction. Readers of this magazine will know that it is our contention that the very existence of scientific laws, and the human "genius" in discovering, applying and refining them, are themselves an indication of the relationship between God, the Creator and Environer of the universe, and the material world in its all its correlative dependencies.

In the Faith synthesis, the "Unity-Law of control and direction" is the key philosophical framework in which to develop an orthodox, dynamic theology that can have an invigorating and enriching relationship with the natural and medical sciences. The need for such a synthesis is essential not only in developing a modern theology that can enter into dialogue with secular, scientific thought, but also in creating the intellectual framework by which to nurture a new evangelisation, especially among the young.

Bishop Marcelo Sanchez Sorondo, the academy's chancellor, believes that it is critical for the new evangelisation to take into account current scientific opinions and positions. This is also clearly in accord with the wishes of the Pope, who stressed the "...urgent need for continued dialogue and cooperation between the worlds of science and of faith in building a culture of respect for man, for human dignity and freedom, for the future of our human family and for the long-term sustainable development of our planet."

Nor is this aspect merely of interest to theologians. Pierre Lena, a French Catholic astrophysicist, stated at the conference:

Science Touching the Edge of Things

Those who are not familiar with how scientific research actually works often have a rather simplified view of men and women in white lab coats doing experiments, plotting graphs and using computers, and if they're lucky "finding" something worthy of a Nobel prize. In fact, there is a dynamic interplay between experimental and observational data and theoretical work, the latter involving mathematical modelling using advanced algebraic and computational techniques.

In the more difficult areas of physics, such as theoretical nuclear physics or the quantum physics involved in cosmology, the procedure may be deemed a success if there is some convergence between the results obtained from the model and the existing data. The model is then used to make predictions, which may or may not be easily testable by experiment.

Recently, an attempt has been made to tackle quantum gravity in the first moments after the Big Bang [cf New Scientist (online): "Galaxies could give a glimpse of the instant time began", 31 October 2012 by Stephen Battersby].

The simplified model of the Big Bang has the universe beginning with a "singularity", a sort of dot that contained the seeds of everything: electrons, atoms, galaxies, etc. In the theory of special relativity, time is part of the fabric of the universe, which is four-dimensional space-time.

As an aside, this means that scientists are quite correct to counter the question which some Christians pose, "What existed before the Big Bang?", with the statement that nothing could have existed because time itself began with the Big Bang, so the idea of a "before" has no meaning. Catholics should have no problem in agreeing with this since St Augustine (in his Confessions) also held that time started with the universe itself, God being outside time.

Einstein's theory of general relativity is a sort of geometrical model of the universe, describing gravitational effects, but it is a model that cannot deal with the interrelatedness of matter-energy at the most microscopic level - especially at times shortly after the Big Bang, when quantum fluctuations are crucially important in the future development of the universe. The problem with general relativity on its own is that as one extrapolates back to time zero, the density of the universe becomes infinite, which is impossible.

This problem can be avoided by using "loop quantum gravity". In this theory, space-time contains a network of space-time loops in which no distance can be smaller than 10-35 metres (the Planck length). The theory uses a "Big Bounce", rather than a "Big Bang", involving the collapse of a previous universe; think of a balloon expanding, then collapsing to an infinitesimal point, then expanding again, but with time itself as part of the balloon's fabric.

Now Abhay Ashtekar, Ivan Agullo and William Nelson of Penn State University [https://arxiv.org/abs/1209.1609v1] have used loop quantum gravity, with parameters taken from data on the cosmic microwave background (relic radiation from the Big Bang or Bounce) obtained over seven years, to examine what structures would have emerged in this Bounce.

Conventional cosmology says that galaxies and galaxy clusters originated during "inflation", an expansion that began about 10-36 seconds after time zero. Quantum variations in the energy field driving inflation led to regions of high-density matter, which later became galaxies and larger structures.

However, the team at Penn State University believes that the energy field should have existed in a weak form before inflation, at the very start of time, from about 10-44 seconds, and that the quantum fluctuations arising in that first quantum instant would have survived inflation. The sizes of the galaxies and galaxy clusters predicted as a result should then match observational data.

The value of the original energy field is unknown, but if the field had just the right strength, and the orresponding distortion in the cosmic microwave background appears, it would suggest that the Big Bounce and space-time quantum loops are real. "It would tell us the conditions of the quantum universe at its birth," says Ashtekar.

The sense here of science entering upon some of the few undiscovered lands of our universe is palpable. Such is the nature of much modern fundamental physics, reinforcing the need for those who reflect upon the ultimate patterns of matter-energy, most obviously in the branch of metaphysics called ontology, to engage with modern scientific thought.