“There is a divine purpose behind this fruitful universe.”
John writes …
I am often asked whether, as a biologist, I think there is life elsewhere in the Universe or whether I believe in aliens (the latter more typical of teenage questioners). In last month’s blog, Graham wrote about this question from the point of view of a physicist who is also intrigued by biology. I am now adding my views on that question. One would think that I could simply answer ‘Yes’ or ‘No’ but I cannot. As I weigh up the possibilities, I cannot reach a firm conclusion – sometimes I think ‘Yes’, sometimes I think ‘No’ but mostly I think ‘I just do not know’. It is a question about which I am truly agnostic.
The first point to consider is the definition of life and that turns out to be harder than we might suppose. In a recent panel discussion on Radio Maria (Science and Faith: Episode 6 – The Biology of Human Life – Radio Maria England) we agreed that it is easy enough to describe life in terms of the attributes and activities that we ascribe to living things. Some of our readers may be familiar with the acronym Mrs Gren which helps us to remember the essential activities of living organisms (Movement, including movement within cells; Respiration, meaning the ‘extraction’ of energy by breakdown of particular substrates; Sensitivity – response to environment etc.; Growth; Reproduction; Excretion; Nutrition). So according to this, a living thing is defined as living because it carries out these activities (but not necessarily all the time). However, in our panel discussion we found it impossible to come up with a stand-alone definition of life – any definition that we came up with was effectively dependent on the descriptors/activities mentioned above. Nevertheless, we agreed that we can tell living things apart from non-living things such a rocks and water, although viruses defy a characterisation as either living or non-living.
The second point is whether life elsewhere in the Universe would be similar to life on Earth or different from it. The problem here is that we cannot envisage any other system of chemistry that might lead to the development of entities that exhibit the ‘Mrs Gren’ characteristics mentioned above. Further, based on the uniformity of the laws of physics, it seems very unlikely that there exist any locations in the Universe where an entirely different system of potentially life-supporting chemistry exists. That leads me to suggest that if there is life on other planets it will be based on the chemistry of carbon whose structure and reactivity is ideal for formation of a wide range of complex biochemicals. Having said that, we need to think about whether the use of carbon would result in similar biochemistry in a distant alien life-form to that which pertains on Earth.
This leads on to my third point, namely what are the essential basic features of chemistry/biochemistry that would enable life to start? As I describe in Chapter 5, many biologists regard the existence of a ‘self-replicating’ molecule (i.e., a molecule that can be copied and passed on to succeeding generations) as an essential pre-requisite for life. However, building larger molecules from smaller molecules requires an input of energy and, as also described in Chapter 5, Nick lane and other biochemists suggest that an ‘energy-gathering’ system (loosely defined as ‘respiration’ in the Mrs Gren acronym) is also an essential pre-requisite. Thus, we have two essentials that must be in place together before there is life. Intriguingly, these two essentials are manifest in the same ways in all living organisms. All possess DNA as their ‘self-replicating’ molecule and, at the heart of all energy-gathering systems there lies the process of creating a gradient of protons (positively charged sub-atomic particles). In seeing these two features we believe that we are getting a glimpse of what the earliest life-forms might have been like.
Fourthly, there is a bit more to the simplest living organism than just the two essentials. In order to prevent dilution by and loss to the surrounding medium, there needs to be containment, That is, a cell with a boundary between the inside and the outside. Further, there must be information to ‘run’ the cell. This is provided by the ‘code’ in DNA (which is the same in all organisms) and I have written in Chapter 5 of the improbability of the decoding mechanisms occurring spontaneously.
My fifth and final point is the question of whether there are other planets capable of supporting life. We noted in the book that Earth is a very special place with many features that help life to flourish. How likely is it that, amongst the vast numbers of planetary systems that Graham mentioned in our March blog post, there exists ‘another Earth’ or even several other Earths? On the basis of those vast numbers we might suggest intuitively that such planets must exist but actually we have no real means of calculating the probability. And if there is indeed another Earth somewhere, how likely is it that life exists there? I have already pointed out that, even on Earth, the origin of life (abiogenesis) seems improbable and yet it occurred relatively soon in the evolution of our planet. Does that mean that it will occur wherever and whenever planetary conditions permit?
I leave you with a thought expressed several times by the late John Polkinghorne, namely that God has created a finely tuned and fruitful universe (For example, Introduction (wordpress.com)). If God the creator has willed it, life is possible on any other suitable planet. But of course we do not know ‘the mind of God’ in relation to our question.
We were very sad to hear of the death, on March 9th, of John Polkinghorne, a leading and influential voice in the science-faith debate. His career in science, working on particle physics and related topics, was very distinguished. He was appointed as Professor of Mathematical Physics at Cambridge University in 1968 and was elected as a Fellow of the Royal Society in 1974. His PhD students included Nobel Laureate Brian Josephson and Martin Rees, the current Astronomer Royal. However, in 1979 he left the world of academic physics to train for the priesthood in the Church of England and thus embarked on a very different style of life.
Over the succeeding years, his contribution to the discussion about the relationship between science and religion has been immense, with an impressive, intelligent, informative and thought-provoking output of books, talks, lectures and videos. But in addition to all this, John Polkinghorne was a wonderful human being – kind, thoughtful and humble. John had the privilege of meeting him on several occasions – on at least two of these we were speakers at the same conferences and have also both contributed to the Faraday Institute’s multi-media resource ‘Test of Faith’. Graham also had the pleasure of contributing, with him, to the ‘God: New Evidence’ series of videos on cosmic fine tuning.
A brief tribute from the Faraday Institute may be found here: Revd. Canon Dr John Polkinghorne KBE FRS (16 October 1930 to 9 March 2021) | Faraday (cam.ac.uk).
“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” Arthur C Clarke, sci-fi author.
Graham writes …
The question as to whether intelligent life exists elsewhere in the Universe is a fascinating one. As someone who was captivated by the sciences, and astronomy in particular, from a young age I have been always intrigued by this mysterious, unresolved issue. Everyone, including myself, is able to express an opinion, but evidence is lacking to be able to arrive at a definitive conclusion. The two major stumbling blocks are, firstly, no one knows how life began on planet Earth, and secondly no direct evidence of alien life has been found despite decades of searching by programmes such as SETI (the search for extraterrestrial intelligence).
The first of these issues is that we do not have a working theory or understanding of the process of abiogenesis, which is the means by which living organisms arise from inorganic material (the proverbial ‘primaeval soup’). Despite intense research activity over many years, this has evaded satisfactory resolution. Some authors have expressed a view that ‘evolution did it’, but of course this only comes into play when there is an existing living population for evolution to act upon. Darwin’s process of natural selection can say nothing about the origin of life. So without an appreciation of how life began here, and in particular how likely or unlikely is the process of abiogenesis, it is difficult to assess whether the Universe is devoid of other life, or conversely teeming with life. The second issue related to SETI raises the question – if intelligent life is abundant in the Universe why has there been a total lack of evidence in the form of direct communication. Where are they all?
Our lack of success in making contact is not just about the vastness of space, but there is also a time-related aspect. There is good evidence to suggest that the Earth was formed around 4.6 billion years ago, and it has taken most of that time for intelligent life to arise. The human species, Homo sapiens, arose about 250,000 years ago, and it is only in recent times that we have developed the technology to potentially communicate across interstellar distances. Although we don’t know how typical our development is compared to extraterrestrial civilisations, we can indulge in a hypothetical comparison to make a point. We can suppose that an alien technological society would discover the energy of the atom, and potentially develop the capability to wipe itself out. Also if we assume that their society, like ours, is energy-hungry, this may result in the threat of a run-away greenhouse effect destroying their biosphere. This raises the question – how long typically would a technological civilization exist? It might be only of the order of 200 years between the development of communications technology and a potentially catastrophic demise. So here’s the point. If we collapse the 4.6 billon year history of planet Earth into a 24 hour period, then 200 years would be equivalent to a very brief 4 milliseconds (four thousandths of a second) – much shorter than the blink of an eye. So the window of opportunity, in time, to communicate with an alien society may be very brief indeed. And furthermore, how likely is it that our window of reception is synchronized with their window of transmission, given the huge sweep of cosmic history?
Without breakthroughs in both of these areas, we come back to the notion that all we can do is express an opinion. I think at the moment it’s ‘fashionable’ to express a view that intelligent alien life is abundant. And a great many ‘celebrity scientists’ do. The argument goes that given enough planets and enough time, life will happen everywhere, despite the fact that abiogenesis appears to be very unlikely. An example is American astronomer and science communicator Carl Sagan, who presumably believed the view expressed by Ellie Arroway, the lead fictional character in his excellent novel Contact (1). Talking to a group of children, she expressed what has become a commonly held view: “I'll tell you one thing about the universe, though. The universe is a pretty big place. It's bigger than anything anyone has ever dreamed of before. So if it's just us... seems like an awful waste of space. Right?” I have to say that over the majority of my lifetime, I too have expressed this belief.
In recent years, I have attempted to gain more of an understanding of the problem of abiogenesis. It is fair to say that I have spent a career effectively as a physicist, so my background is not exactly ideal in allowing me to understand the complex biological issues associated with the origin of life. However, working with John Bryant in writing the book, and co-leading conferences, has spurred my interest in biology. I now find myself reading books about organic chemistry, life and the origin of life! I do however have to choose the authors I read very carefully, as I don’t have a lifetime’s experience of the topic to determine the authority, or otherwise, of what I read. Having said that, I now find that doubts about a Universe teeming with life have crept in. From what I grasp from my attempts to understand the biology of life, I have begun to appreciate the magnitude of the problem. Even my rudimentary knowledge gives me an appreciation of the beauty, elegance and especially the complexity of the mechanisms involved in the creation and sustenance of a living organism. In trying to understand how it all started are the enigmas of the curious but vital relationship between nucleic acids (information) and proteins (the molecular work horses) and the apparently irreconcilable ‘chicken-and-egg’ type issues that John has explained so well in his contributions to the book. At this stage of our scientific understanding of abiogenesis we have to say that it remains a mystery.
So what are the chances of life arising from inanimate material? Many years ago mathematician and physicist Fred Hoyle (of Steady State Theory fame) likened the probability of abiogenesis as comparable to “the chance that a tornado sweeping through a junkyard might assemble a Boeing 747 jumbo jet.” His estimate of the odds of this happening is one in 10 to the power of 40,000 (that’s 1 with 40,000 zeros) – an extremely low probability. I have no idea how he came to such an estimate, but the truth is that we are not able to estimate the probability of abiogenesis occurring on this, or any other planet. Hoyle’s argument is now accepted as erroneous as it considers the unlikely scenario of advanced life forms arising directly from inorganic material.
One thing we do have some idea about is the number of planets in the visible Universe. Our home galaxy The Milky Way comprises around one hundred billion stars, and we can estimate the number of galaxies also as approximately one hundred billion. This suggests the number of stars in the visible Universe is approximately 10 to the power 22 (that’s ten thousand billion billion, if that means anything to anyone). We also know that most stars have a planetary system, so if we suppose that each star has one planet orbiting in the circumstellar habitable zone that is a huge number of planets where, potentially, life may arise. However, this too is not straightforward.
As John writes in Chapter 5, cradle Earth that has nurtured complex life is itself special. It orbits a star, the energy output of which has remained relatively stable over billions of years. The Earth is at the ‘right’ distance from its star, so that water may exist in liquid form. Its size is just sufficient to allow it to retain its atmosphere and oceans over billions of years. It possesses a radiation shield by virtue of its magnetic field. It supports tectonic activity which recycles material, especially carbon. The Earth is also accompanied by a relatively large moon, which helps stabilise Earth’s spin axis producing steady climatic conditions. Among the many planets existing in the visible Universe, the Earth may indeed be very rare. The notion of the ‘rare Earth’ was formalised in 2000 by Peter Ward and Donald Brownlee (2).
At the end of all this, we really have no other option than to say the existence of life elsewhere in the Universe is still open to speculation. Frank Drake wrote down an equation in 1961 (the Drake Equation) to estimate the number of communicative extra-terrestrial civilisation in our galaxy. And now, after 60 years of effort, we still do not know the values of the parameters in this equation to allow us to make a definitive judgement.
Graham writes …
This post is the first in a series looking at the implications of life elsewhere in the Universe. We start by considering our neighbouring planet Mars.
Way back in September 2019, a couple of good friends Pat and Sharon surprised me with a ‘Boarding Pass’ for Mars 2020. At first, I had no idea what it was about but they explained that there was to be a NASA launch of a mission to Mars in July 2020. They had registered my name on a data base, and this would be transported to the surface of Mars. As you can imagine, I was quite excited and inspired by the prospect that my name (in whatever form) would forever reside on the Martian surface. I printed out my ‘pass’ (see picture) and pinned it on my office notice board, where it remained unnoticed until this week.
Indeed, this week saw the arrival of the Mars 2020 mission. On the evening of 18 February 2021, I tuned into a live broadcast on NASA TV from the JPL Perseverance Rover Mission Control room to watch the events of the rover landing strategy unfold. After its 203 day, 472 million kilometer journey, the conical capsule carrying the rover hit the upper atmosphere of Mars at 20.48 GMT travelling at about 20,000 km per hour (5.6 km per second). Seven minutes later at 20.55 GMT the rover arrived successfully on the surface. Watching the broadcast, the descent time seemed to flash by. To reduce the speed of the rover to effectively zero in such a short amount of time required a pretty brutal and complex sequence of events (see NASA descent videos – animation and actual video coverage). Just 80 seconds after atmospheric entry, peak heating occurred, with the heat shield reaching temperatures of about 1,300 degrees Celsius. Ten seconds after this, the peak deceleration of 10 g occurred. At this rate of deceleration, the capsule speed is sapped at rate of about 1 km per second for each ten seconds of flight. Finally, a combination of parachute and retro thrusters brought the rover to rest on the surface in a 1200 km diameter crater called Jezero.
This particular landing site for Perseverance, was strongly prescribed by the principal mission objective – that is, to investigate the prospect that microbial life still inhabits the surface (or more likely the subsurface) of the Red Planet. So why Jezero Crater? Over decades, an armada of Mars orbiting spacecraft have looked down on the surface and imaged the spectacular landscape. Mars has the distinction of having the largest volcano (Olympus Mons) and canyon (Valles Marineris) in the Solar System.
However, perhaps the most surprising feature of the topography is the unmistakable evidence that water once flowed freely upon the surface. Scientist have estimated that around 3.8 to 3.5 billion years ago, the climate of Mars was warm and wet – effectively, the planet was a water world not unlike Earth today. Evidence of water features – tributaries, river deltas, flood plains – are abundant. So where has all the water gone? As Mars is only about half the size of Earth, with a surface gravity of 38% of ours, the atmosphere of Mars has slowly leaked away into space over the last 3.5 billion years. Current atmospheric pressure is only 0.7% of Earth’s, and any water on the surface would quickly evaporate. So now Mars is dry and arid.
So, all those years ago it is believed that Jezero was lake, with a river inlet and outlet, and Perseverance rover’s landing site is located near the inlet. The rover has the ability therefore to look for likely sites in the lake bed and river delta where Martian microbial life might still reside. This is likely to be found in the subsurface rocks, so the rover has the capability to drill into the surface to produce core samples. These precious samples will subsequently be left on the surface to collected, and returned to Earth for detailed analysis. The methodology of this retrieval process is quite torturous, and is perhaps the subject of another blog.
What then is to be learned from all this? It would be truly remarkable if life was discovered, and it was unambiguously based upon biology unlike that found on planet Earth. This would certainly be a paradigm-changing discovery, having great significance for our understanding of life elsewhere. However, another outcome could be that Martian life is found to be based on the same DNA code that is universal on Earth. This is entirely possible due to the fact that Earth and Mars are not biologically quarantined from each other. It has been known for many decades that chunks of rock from Mars can be found on Earth, and no doubt similarly bits of Earth reside on the Martian surface. The main mechanism accounting for this surprising situation is that highly energetic comet or asteroid impacts on Mars can blast rocks into orbit around the Sun, which can subsequently encounter the Earth. Presumably the reverse route is also viable. Of course, another overall mission outcome could be that no convincing evidence of microbial life is found. Only time will tell. For more information about the prospect of life on Mars, I can recommend Paul Davies’s book The 5th Miracle*.
Finally, it is worth pointing out that there are other places in the solar system where life may reside and where biological quarantine conditions are more stringent. Orbiting spacecraft missions to Jupiter (Galileo) and Saturn (Cassini) have shown that Jupiter’s moon Europa and Saturn’s moon Enceladus have significant water oceans beneath a thick surface crust of ice. The heat required to maintain this liquid state in both moons is generated by tidal heating. The source of this heating is likely to be active thermal vents on the ocean bed, around which conditions for the nuturing of life may exist. Although this is an exciting prospect, the opportunity to investigate this hypothesis is likely to be some significant time in the future. The task of delivering a submarine, robotic probe to these distant worlds is an extremely challenging one from the perspective of rocket science and spacecraft engineering.
* Paul Davies, The 5th Miracle: the Search for the Origin and Meaning of Life, Chapters 8 & 10, Simon & Schuster, 2000.
John writes …
I am composing this in January 2021, a month in which the UK has entered another phase of ‘lockdown’ in order to control the spread of the coronavirus SARS-CoV-2, which causes the disease Covid-19*. Our lives are very restricted but thankfully we are encouraged to go out in ones or twos or small household groups for exercise. I have had much more time to observe and consider the natural world in a different way from research work in the lab. Going out regularly in the same locations, whether on foot or by bike makes me very aware of the cycle of nature. Days are already 30 minutes longer than at the winter solstice. The buds of deciduous trees are beginning to exit from dormancy and some cold-tolerant plants and trees have started to flower.
The annual cycle of seasons was of course also known in Biblical times although the specific reasons for the seasons (the passage of the Earth around the Sun, coupled with the tilt of the Earth’s axis) were not known. Indeed, from early in human history, any group of people who did not live close to the equator (where daylength is constant or nearly so) would have been aware of the annual changes in season and the resultant changes in the biological world, including new growth, flowering and fruiting, bird migration and so on. In the Bible we can also see a sense of wonder at the natural world. Psalmists were amazed and in awe of the starry heavens; Job wrote extensively and wonderingly about both physical and biological aspects of nature; Jesus himself talked about the beauty of wild flowers. And we, many centuries later, also react in awe and wonder as we know about and understand so much more about our planet and the ‘balance of nature’ thereon (see especially Chapters 5 and 8 of the book). Indeed, as I have described in the Preface and in another blog (Magic and Metamorphosis), my wonder in response to the natural world was one of the factors that led me into science.
All this brings me to the BBC, Britain’s national non-commercial broadcasting organisation. Currently, they are running a weekly series (five episodes in all) called A Perfect Planet, with commentary by ‘national treasure’ David Attenborough (see BBC One – Introducing A Perfect Planet and also BBC iPlayer). The filming is truly wonderful, bringing us everything from volcanic eruptions through ecosystem dynamics, predator-prey relationships to the minutiae of certain plant-animal interactions. In the latter category we learn about the role of the fig wasps in pollination of figs (Ficus species). It is a story as specific as, but even more bizarre than the pollination of Yucca that we describe in Chapter 8 (see Fig wasp | insect | Britannica).
In the TV programme, we learn about the essential role of tectonics and volcanoes, about being the right distance from the sun (the Goldilocks zone). We learn that ‘Our planet is one in a billion’ and that … ‘incredible, awe-inspiring life is driven by its natural forces’. And, in the final episode we will learn about what humans have done to the balance of nature, leading to the ecological crisis and the climate emergency.
Overall, it is as if someone at the BBC has read From the Big Bang to Biology … and has set out to make a wonderful film of the book. But there is of course one thing missing. One of the features that comes over strongly in the films is a sense of awe and wonder that is almost religious in tone but there is no mention of God. This is not a criticism of the programmes - they are not part of the BBC’s religious broadcasting – and yet we wonder whether the sense of awe and wonder that comes over so strongly will lead to any viewers, or indeed, any members of the production or presentation teams, to ask deeper questions, questions that require more than science and good filming to reach an answer.
* This raises the difficult topic of disease and suffering. I do not deal with it here but readers may be interested to look at Café Théologique an online interview: A God of Genes and Viruses - Prof John Bryant.
See also Perfect Planet: A Statement in Response - Ruth Valerio.
You may be surprised to learn that this brief contribution is about something that happened 19 years ago. So, you may also be asking why would this be of interest to anyone after all this time? For me, the events that occurred in November 2001 were the first tremors which heralded the personal revelation that there was more to the world than the bits described by the physicists. The shockwaves that subsequently radiated from those tremors were to profoundly change my life. It was then, at age 51, that God chose to reveal Himself to me, and I have no idea why He chose that time in my life, or why He decided to do it at all.
Perhaps a bit of back story would be helpful here. I was raised in a loving family that had no explicit faith in God, and consequently church attendance, or any other manifestation of religion, played no part in my up bringing. From a very early age I was captivated by science, which steered my education to culminate in a doctorate in mathematical physics in 1975. Subsequently, I spent a very fulfilling career in space science and engineering, both in industry and academia, before retirement in 2010. However, it was during busy years at Southampton University that I became a Christian. How this came to be was very much related to the issue of ‘science and faith’, and I wish to say something briefly about this transformation in this account. Prior to this extraordinary event, I would have described myself as a tolerant agnostic, firmly entrenched in the notion that science had explained everything to the extent that any form of god was entirely irrelevant.
My story starts in the unusual setting of a family holiday in Guernsey in the summer of 2001. Time by the pool gave me plenty of opportunity for reading and thinking, and I experienced a rare, startling insight about the nature of the Universe! This was along the lines of the universe is defined by our existence within it. This is something that these days we call cosmic fine-tuning. The argument goes that the fundamental constants of the laws of nature have to take very precise values in order that life of any form can exist in the Universe. This kind of notion has been with us for some time in the form of something called the anthropic principle, that can be expressed as – the laws of nature must be constrained to allow human existence. So why the big deal? The startling character of the insight arose because of the degree to which the fundamental constants have to be finely tuned. Most scientists are hard headed about this, and agree that if it wasn’t so we wouldn’t be here to think about it. And they are quite right. But for me, by the poolside, it was the precision of the fine-tuning that was startling. You could say that the Universe is an extremely unlikely place. Put another way, if you saw a well-shuffled pack of cards being dealt in perfect suit and numerical order, you might wonder how this could happen. Was it by chance (odds of 1 in 10^68) or was there more to it? Something behind it?
Cutting a long story short, I pondered the options, and after many weeks of reflection I had arrived at a place in which I was comfortable with the notion that there may be such a thing as a Creator God. Given my background, this was not an easy journey but it did put me in a position where I could consider attending an Alpha course at the local church in the Autumn of 2001, and the rest is history as they say. An encounter with the numinous occurred and finally convinced me that there was such a thing as the ‘spiritual realm’.
One thing I have learned from all this, and in particular in the context of courses such as Alpha, is that people are convinced not by endless academic discussion of the issues, but rather by the simple means of personal experience of God transforming power in their own lives, and in the lives of others.
Read my story in more detail in ‘From the Big Bang to Biology: Where is God?’ by Graham Swinerd and John Bryant (Nov 2020). This blog post is adapted from a contribution to the blog section of the Faraday Churches website. See the original here.