Could there be anything before the Big Bang? Does this question even make sense? The legendary British scientist Roger Penrose thinks it does. He has come to believe that the universe is eternal, and that our universe is just one aeon in an endless cycle, like an Escherian stairwell. An extraordinary view, more akin to the Hindu Rigveda philosophy of a universe eternally in flux.
The Standard Big Bang Model
Current-day standard cosmology has it that our universe began about 13.72 billion years ago with the Big Bang. Although the Big Bang theory gives an exceedingly accurate description up to the very early moments of our universe, the actual Big Bang itself (at time t0) does not form a part of it. Extrapolations up to the Big Bang itself result in a singularity, which basically means that our scientific theories themselves break down and are no longer valid at that point. The Big Bang is considered as a singular boundary of information. Asking what might come “before” the Big Bang is a meaningless question, like asking what lies south of the South Pole.
Before the Big Bang?
But that doesn’t prevent scientists to keep on trying to wrap their heads around this “impenetrable barrier”. In 2010, the eminent British scientist Roger Penrose together with Vahe Gurzadyan claimed to have found evidence in the cosmic microwave background in the form of concentric circles that could possibly point to an era before the Big Bang. These circles are supposed to be a kind of gravitational ripples, resulting from colliding black holes in the “previous” universe, hereby providing us a window “beyond” the Big Bang. [1] It is comparable to ripples in a pond after you have thrown a heavy stone in it. Long after the stone has disappeared below the surface, you will still have a dissipating web of peaks and troughs, giving a clue as to what has happened.
Penrose has come to believe that there is an era before the Big Bang and, what is more, this era somehow gives rise to an extremely low degree of entropy, as a result of which entropy can steadily increase after the Big Bang. In his book Cycles of Time, Penrose extrapolates this idea even further: our universe is just one of many in an endless cycle, where each Big Bang initiates a new universe following the one before, each time resetting the entropy to an extremely low value. [2] His cosmology reveals an eternal universe, reminiscent of an Escherian stairwell, endlessly going up and down at the same time.
At the very beginning: no mass, no metric, no time
Basically, Penrose’s reasoning boils down to the idea that as we rewind the movie of our universe and come very, very close to the Big Bang, the temperature and energies get so high as to render the rest mass of particles negligible and eventually to make it disappear altogether. But as this happens, we enter into a very strange phase of the universe. In Cycles of Time, Penrose goes to great lengths to explain that it is rest mass which determines the metric of the universe and which determines the rate of clocks. However, for massless particles, like photons, whizzing at the speed of light, there is no such thing as time. There is no “tick of the clock”, so to speak. It is very difficult to imagine, but for a massless particle, there is no difference between the instantaneous “now” and eternity.
When we enter this phase of the universe where there is no longer any rest mass, the metric of General Relativity no longer applies. The geometry of the universe becomes radically different. Instead of the metric of General Relativity, we have to use another kind of geometry, a so-called conformal geometry without a metric, i.e. without any distance.
The end of eternity
Next, Penrose envisages the very far future of our universe, long after the last star has gone out, and all the matter in the universe has eventually been swallowed by black holes. When the overall background temperature of the ever-expanding universe finally drops below the surface temperature of black holes, they will – very slowly – start evaporating due to Hawking radiation. As a result, still according to Penrose, all particles with rest mass will eventually decay into massless radiation. Once again, conformal geometry without distance, without the passage of time, will reign supreme.
From aeon to aeon
With a very ingenious mathematical construction using conformal geometry, Penrose maps the “end of time” (the era when there are only massless particles of radiation) to the big bang of a new era (with also nothing but massless particles). The vanishing of matter and time (and distance) results in a smooth conformal boundary of space-time from which a future universe will emerge. Our universe is but an aeon in an infinite sequence of aeons.
Very interestingly, the origin of Penrose’s extraordinary cosmological view has a curious personal twist. Gustaaf C. Cornelis, a Belgian philosopher of science specialised in the field of cosmology, recounts the story of Penrose giving an interview for the Dutch journal NRC-Handelsblad in 2011:
“In this [interview], he reiterated that in 2005 the thought of residing in a universe with only gravity waves and light particles remaining was depressing to such an extent that he was looking for a new interpretation framework.” [3]
Highly controversial
Let it be very clear: Penrose’s model is highly controversial and goes straight against the inflationary model which has gained wide acceptance over the years, and not without good reason for that matter: the inflationary model provides by far the best explanation of everything we can observe in the universe.
Roger Penrose himself is very aware of the fact that his model is not without serious difficulties. To name just one, his model presupposes that all matter in the universe (i.e. all particles with rest mass) will decay into massless radiation. It is still very far from clear that this will actually happen. [4]
But whether Penrose’s model is “true” or not, that doesn’t matter. Science is about building and searching for models, and weighing one model against the other against observational data, and not about deciding whether a model is “true” or “real”.
Theological curiosities
Although Penrose himself is an atheist [5], he is aware of the fact that his theory of an infinite cycle of aeons “is a bit more like Hindu philosophy” than the standard Big Bang theory, as he himself puts it. [6] Be that as it may, for him this is nothing more than a theological coincidence, a pleasing curiosity. [7]
Although this theological coincidence doesn’t play any role whatsoever in Penrose’s research, it can be easily imagined that an eternal cosmology in whatever form could be troublesome for some theologians. For instance, for the American Christian philosopher and theologian William Lane Craig, well-known from his public debates with renowned cosmologists like Sean Carroll, the idea that the standard Big Bang theory seems to favour an absolute beginning of the universe (which it doesn’t) plays a crucial role in his apologetics. Whatever the outcome might be, at the very least it shows that current-day cosmology for some theologians is found to resonate with the Christian account of creation.
Creatio continua?
Other theologians however will be quick to point out that even an eternal universe is not incompatible with the idea of a Creator. Even if there is no creation out of nothing, God can still be invoked as the ‘Ground of Being’, as the one who ‘sustains the world’, seeing the concept of creation as ‘allowing the universe to exist’ (cfr. the theological notion of creatio continua, continuous creation). The Dutch theologian and philosopher of religion Taede Smedes ingeniously tried to solve this conundrum by stating that the Big Bang theory neither confirms nor denies the idea of acreation from nothing, because scientific theories are theologically ambiguous. [8] We can easily extrapolate this statement to eternal cosmologies as well.
Metaphysical superfluity
However, stating that scientific theories are theologically ambiguous is very short of admitting that scientific theories are simply not in need of superfluous metaphysical or theological add-ons. The universe does not need anything to sustain it. ‘Being compatible’ with science is not enough to warrant the addition of supplements to scientific theories which do not have any explanatory value and are not needed to account for scientific evidence.
Relic of the past
Whether Penrose’s theory of eternal cycles of time is flawed or not, that is not the point. Currently there are at least a dozen competing models of eternal cosmologies, each of which runs into heavy criticism. And whatever model will turn out to gain acceptance over others will be decided upon by scientific criteria, not by religious ones. It is not up to religions to make claims about how the universe works.
What matters is that Penrose’s model is a completely self-contained scientific theory which accounts for the entire universe without having to rely on anything outside it. Insisting that having a completely self-contained scientific model which accounts for the observational data is not enough is a relic of an outdated view of the world, linked to an obsolete way of thinking, predating the era of science.
Notes
This blog post was originally published on January 14, 2016, at:
[1] See Gurzadyan, V.G. and Penrose, R., Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity, (November 2010) in
http://arxiv.org/ftp/arxiv/papers/1011/1011.3706.pdf (accessed January 11, 2016).
[2] Penrose, R., Cycles of Time. An Extraordinary New View of the Universe, London, Random House, 2010.
[3] Cornelis, G. C., Het geheim van de kosmologie ontrafeld. Ten dienste van een waarheid, Brussel, ASP editions, 2012, p. 320 (and footnote 1222, p. 409), my translation. A highly recommendable work on the scientific developments leading up to current-day cosmology, in Dutch (title: The Secret of Cosmology Unraveled. In Service of a Truth).
[4] To this day, it is not certain that electrons will ever decay, and recent research revealed that the minimum life span of electrons is at least 5 quintillion times the age of the current universe (6.6 x 1028 years). See: Agostini, M. et al., Test of Electric Charge Conservation with Borexino, Phys. Rev. Lett. 115, 231802 – 3 December 2015,
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.231802 (accessed January 11, 2016).
[5] See the interview with Roger Penrose, Big Bang follows Big Bang follows Big Bang, BBC News, 25 September 2010,
http://news.bbc.co.uk/today/hi/today/newsid_9032000/9032626.stm (accessed January 11, 2016).
[6] Brean, J., Sir Roger Penrose: Scientific Heretic, (7 October 2008),
http://www.uncommondescent.com/science/sir-roger-penrose-scientific-heretic/(accessed January 11, 2016).
[7] Ibid.
[8] See Smedes, T.A., God en de menselijke maat. Gods handelen en het natuurwetenschappelijk wereldbeeld, Zoetermeer, Uitgeverij Meinema, 2006, p. 111, in Dutch (title: God and the Human Dimension. God’s Acting and the Scientific Worldview)
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