John writes ...
I have worked directly or indirectly on DNA and genes from my PhD student days and throughout my research career. My focus was at the interface of biochemistry and genetics, an area of science that we call Molecular Biology and with which I am very familiar. It is replete with marvellous molecules and mechanisms, although, for those of us who are practitioners, it is too easy to take those marvels for granted. We need to ‘stand and stare’ perhaps for just a few minutes to remind ourselves that the whole topic is amazing.
Let me start with the genetic material itself, DNA. DNA molecules are not really complex, although they can be very long (long in relation the dimensions of living cells). DNA molecules are polymers, that is they are built of many individual components linked together. These individual components are called bases in biochemical shorthand and there are only four sorts – as I said, DNA is not a complex molecule – and they can occur in any order. This simplicity fooled scientists for a long time: how could such a simple molecule carry genetic information? DNA was discovered in 1869 and was shown to be present in chromosomes early in the 20th century but it was not until the end of World War II that this key role of DNA was finally demonstrated beyond doubt. And of course, that demonstration led to extensive further research, including the elucidation of its structure by Watson and Crick – and others – in 1953.
All the information required for the development and second-by-second life of all organisms is encoded just in the four bases of DNA, the specific information coming from the order and the number of bases in subsections of DNA molecules that we call genes. Further – and this fact still fills me with amazement – all living organisms on Earth read the code in the same way. Every living organism is related to every other, consistent with the idea that there was just one origin of life (abiogenesis) and all life-forms are derived from that common beginning.
Caption for image: In bacteria, the DNA molecules are circular and, in addition to their main DNA molecule, they often have mini-circles that carry just a few genes. We constructed artificial mini-circles by splicing different pieces of DNA together in order to study the interaction of a particular protein (see below) with particular structures in DNA. The interaction is seen here under an electron microscope. Image copyright © Sara Burton, John Bryant and Jack Van’t Hof.
But there is more. The information in DNA must be passed on. Every new cell needs a faithful copy of the genetic information from its ‘parent’. This is where the famous ‘double helix’ comes in (if you are not sure what a helix is, think of a ‘spiral’ staircase. A spiral staircase is actually not a spiral but a helix). A molecule of DNA consists of two helices wound round each other and which are held together because of specific abilities of the bases to form pairs with each other. Using just the initials of the bases to indicate their names, A in one helix can only pair with T in the other; similarly, G can only pair with C. I’m sure you can see that this immediately provides the means of passing on the code faithfully. If the two helices separate, then each single helix directs the synthesis of a new partner helix. For example, a T in the pre-existing single helix dictates that there must be an A at that position in the new helix. The structure of DNA means that it can direct its own faithful copying. That is both awesome and beautiful in its simplicity. If a human engineer had come up with this, we would say that he or she was a genius. As a Christian I say that the genius here is God.
Thus the genetic code is safely passed on from generation to generation, but what does the code actually do? Well, it directs the synthesis of proteins, the cell’s working molecules. There are thousands of different sorts, many of which are enzymes – proteins that carry out biochemical reactions. Proteins are polymers (see above) built with amino acids, of which there are 20 types that vary significantly from each other in shape and size. The shape of a protein, essential for its function, depends on the particular array of amino acids – overall number and the order of different types within the molecule. Some proteins are small and quite simple, others are very large (in molecular terms). A code based on just four bases (read in groups of three) in DNA tells the cell the order in which to put the amino acids in a protein.
How does this happen? How is the code translated? The answer is not ‘Google Translate’ as one school student suggested to me! I’d like you to envisage the code as a row of beads of four different colours and the cell’s pool of amino acids as a pile of LEGO (TM) bricks of several different shapes and sizes. Those bricks do not fit onto the beads. In the same way, an individual amino acid cannot on its own recognise three bases and line up with them. The answer to this conundrum is in the form of adapter molecules which can recognise an individual amino acid and the three-base code that specifies that acid. These adaptor molecules ensure that the amino acids are built into proteins in the right order. It is an amazing mechanism and we have no understanding of how it evolved. This leads back to a point that I made at the beginning of this article. In Chapter 5 of the book, I wrote ‘… I cannot help think that we biologists are so used to this that we have become a little blasé.’ When we pause to think a little more deeply we can only react with awe and wonder at God’s magnificent creation.
Note: I wrote a revised version of this blog for the Faraday Institute’s Faraday Churches web page. You can find it here, with a brief introductory paragraph from Ruth Bancewicz.
Graham writes …
Sometimes when John and I are leading a conference, we ask people to speculate about what is the most complex object we have discovered in the Universe. After a few responses, usually related to celestial objects, we guide the delegates by suggesting that there are many of these objects in the conference venue – the human brain! The working network of the brain has around 100 billion neurons (brain cells), resulting in the order of a million billion neuronal connections. In some way that science has yet to fully understand, this leads to mind and consciousness, as the mechanisms that give rise to these attributes remain a mystery. Given that mind and consciousness are the things that make us human, and are fundamental to our daily experience of ourselves and the world around us, it is remarkable that we have yet to comprehend how this works. One of the biggest scientific mysteries resides inside our head!
Earlier in the year I tuned in to an online meeting of Christians in Science to hear a talk called Am I just my Brain? by Dr Sharon Dirckx. As you may know by now, I am not exactly well-qualified to comprehend the subtleties of neuroscience, but I was delighted that the talk was pitched at my level, and I was also bowled over by what she had to say about our current understanding (or controversy) about ‘mind’.
Dirckx (pronounced ‘Dirix’) is currently a Senior Tutor at OCCA (Oxford Centre for Christian Apologetics), after acquiring over a decade of hands-on experience in functional magnetic resonance imaging. Subsequently, I have acquired a copy of a neat little book that she has written with the same title (1). It was a good read, that I can recommend. This little book has much to say about a great many things, but I would like to say something about two topics in particular.
Firstly, that there is still debate about where the human mind ‘resides’.
Given the importance of mind, I was really quite excited by the idea that the practitioners and philosophers are still discussing this issue. Afterall, I am effectively my mind. It is where I play out my inner life, it is where my memories reside (and effectively, my memories are what make me me) and it is where I organise and plan my life. The Oxford English Dictionary sums up ‘mind’ concisely as:
The seat of awareness, thought, volition, feeling and memory.
The debate about where exactly this seat resides has apparently gone on for a very long time, and still continues today. Having said this, it is fair to say that the scientific view is that the mind is the brain. All the complex facets of my inner life are just the firing of neurons, and the seat of mind is just brain chemistry. In this view, I am indeed just my brain.
Another option is that the brain generates the mind. Once the brain reaches a certain level of complexity, mind emerges as something new and distinct, the word ‘distinct’ suggesting that the seat of the mind is controversially beyond the brain. In this scenario, given that mind is a product of brain, the mind ceases to exist once the brain dies.
A third option offered by Dirckx is that mind is beyond the brain. Mind and brain are two distinct ‘substances’ that can interact, but they can also operate independently of each other. In this scenario, the brain can influence the mind, but the mind can also interact with the brain and the body – there is two-way traffic as, for example, when the body manifests psychosomatic illness. Clearly, this option is not recognised by the materialistic brand of science that pervades contemporary thinking on these things. Neuroscience can only recognise the first option.
The second topic is to do with whether, as human beings, we have free will – again a bone of contention for scientists and philosophers over many years. This discussion continues in the more contemporary setting of YouTube – you will find pages of responses if you just enter ‘free will’ into the search box.
Why is this particularly of interest to Christian believers? It is a fundamental facet of the Christian faith that we are free to choose. God is not in the business of interfering with our free will. We can choose to go God’s way, or our own way – in other words we can choose to follow him. As God’s creations, he could have programmed us to follow and love him, but then the notion of love is meaningless in a world full of what effectively would be a population of programmed human ‘robots’. This is made clear by Jesus when he said “So I say to you: Ask and it will be given to you; seek and you will find; knock and the door will be opened to you.” (2) It is our choice whether or not to ask, seek or knock.
However, there are many so-called ‘hard determinists’, who refute our ability to make free choices, despite the common human experience that we do this all the time. Hard determinism is a viewpoint that the human brain and the decisions arising from it are wholly determined by prior causes. In other words, the human brain is likened to a mechanism that operates within the confines of fixed processes, and it is this attribute that prohibits the possibility of free will.
In her book, Dirckx dismantles the philosophy of hard determinism in a beautifully concise section of her book (3) by asking three questions – is it internally consistent?, does it have explanatory power? and can it be lived? I do not wish to repeat her arguments here but just give a summary, with an emphasis on her third question.
If I lived as a cause-and-effect machine, then any personally held belief is undermined – and this includes a belief in hard determinism itself, of course! Rather my precious conviction would just be the inevitable consequence of my neurons firing. If a determinist says we don’t have free will, and requests that I evaluate the proposition, I am unable to do this freely in the absence of free will. Effectively I would have no rationality – I would not be able to choose freely between concepts. Similarly, if you can’t make a free decision then there are other important consequences. I would effectively have no creativity, as I would be unable to choose freely between creative ideas. I would have no ability to love, as I would be unable to choose freely whether to embrace someone in that way. Perhaps the most significant issue is that I would have no personal culpability. In contemporary society, we are all considered to have moral responsibility, and are therefore accountable for our actions – I have a choice whether to do right or wrong. If this is not so then hard determinism threatens to unravel the cornerstone of moral responsibility and the need for justice. In other words, if you use the consequence of determinism as a defence in a court of law, the judge would most likely tell you, in no uncertain terms, to go away and rethink.
The scientific basis for saying that we do not have real freedom to make choices is the idea that the laws of physics allow us to predict the future based on knowledge of the current initial conditions. In other words, if we have knowledge of the current state of all the particles in your brain, then the laws lead us to a uniquely defined future state, therefore making freedom of choice an impossibility. However, this argument disregards the fact that physics is not yet complete. In fact, all of our laws of science – the mathematics we write down to make such predictions – are very much approximations to the reality, which is governed by the powerful agencies that enact what we call the laws of nature. For more detail, see the discussion in Chapter 2 of the book (4). Also, to make such claims when the path from fundamental physics to understanding mind and consciousness is completely uncharted, is, to me, the height of scientific hubris.
Dirckx’s argument takes the discussion in the opposite direction, based upon the consequences if hard determinism reigns. Either way, the bottom line is that we live in a manner in which the decisions we make mean something and these are made by volitional people, and not by cause-and-effect machines.
(1) Sharon Dirckx, Am I just my brain?, The Good Book Company, 2020
(2) The Holy Bible, Luke's Gospel, Chapter 11, verse 9 (NIV)
(3) Reference (1), pp 85-88.
(4) Graham Swinerd and John Bryant, From the Big Bang to Biology - where is God?, Kindle Direct Publishing, 2020, Section 2.4
John writes ...
Our friend Dr Ruth Bancewicz is Church Engagement Officer at the Faraday Institute for Science and Religion in Cambridge. She has recently written an open letter to the Church of England Newspaper to which we have also posted a link on our book’s Facebook page. Her letter is entitled ‘Starting new conversations about science and faith’ and her opening discussion is focussed on something that is dear to both my intellect and my emotions, namely connectedness and inter-connections in nature. Ruth focusses on the extensive network of fungal mycelia that exists beneath the woodland floor providing myriad interconnections between the trees, as I also describe in Chapter 8 of our book. The ‘wood-wide web’, as some have called it, is a beautiful example of mutual support and enablement, leading to fruitful growth of both trees and fungi (in the latter, the appearance of mushrooms/toadstools is a sign of their fruitfulness). For readers who are particularly interested in finding out more, I recommend Merlin Sheldrake’s book Entangled Life.
Ruth suggests that a truly effective congregation should be a network of people, often working behind the scenes, perhaps even hidden, but providing extensive support and help in a mutually dependent way. Further, the establishment by the Church of England of the Anglican Science Commission emphasises the roles of scientists in congregations being active members of such networks. In the network beneath the forest floor one of the things that is shared is molecular information, often in the form of what biologists call ‘signalling’ molecules, molecules whose evolved purpose is to elicit a biological response. In the case of the scientist-Christian this may mean interpreting recent scientific findings and helping our fellow-Christians appreciate the beauty and wonder of the created order. We hope that our readers appreciate that aspect of our book and we note that Ruth herself discusses it at length in her recent book, Wonders of the Living World: Curiosity, Awe and the Meaning of Life. Or we may be able to stimulate discussions about the ethics of applying new knowledge or new science-based techniques or inventions (as is currently happening for genome editing and for AI). Or it may simply be a matter of just ‘being there’, one of thousands of members of the scientific community for whom science is not a threat to faith but a stimulus for worship.
Graham and John write ...
As Graham discussed in Part 2 of this series of posts, astronomers have discovered thousands of planets orbiting other stars; indeed, the number of new discoveries of exoplanets, as they are called, continues to grow on a daily basis. Many of these are located in the habitable zone of their sun, which spurs inevitable speculation about whether intelligent alien life resides there. However, this does not just depend upon the number of suitable planets but also upon the likelihood that life will occur given suitable conditions. The latter question was addressed by John in Part 3: abiogenesis on Earth looks to be extremely unlikely and remains a mystery but life has originated on our planet. Indeed, it has given rise to beings such as ourselves, capable of contemplating such things.
Coming at the problem from two different directions, it is fair to say that we came to same conclusion – clearly there is currently insufficient data to say whether we are alone in the Universe or whether the Universe is teeming with life.
As we mull over these issues, our opinions about the abundance or otherwise of life elsewhere change, almost from day to day. At this moment for example, Graham is of a mind that intelligent life is only sparsely distributed throughout the Universe, because of the improbability of abiogenesis. But are we missing something here? John reminds us that there is evidence to suggest that on planet Earth life arose about 4 billion years ago, as soon as conditions became physically suitable. What life there was also survived the bombardment era, when the planet was repeatedly struck by large debris left-over from the birth of the Solar System. Perhaps abiogenesis is not as improbable as first appears. So, we might ask, as Paul Davies did in his splendid book The 5th Miracle (1), if the laws of nature are somehow bio-friendly. In other words, are they rigged in favour of life? Currently, there is no indication that this is so, or if it is, how it would work.
So, what issues are posed for the world’s religions, and for Christianity in particular, if intelligent extra-terrestrial (ET) life does exist? This has been discussed in some detail by our friends at BioLogos in an online article by Deb Haarsma: ‘What would life beyond Earth mean for Christians?’. This includes a 90-minute video of presentations from the 2019 BioLogos Conference, featuring Deb Haarsma (theology), Jennifer Wiseman (astronomy) and Stephen Freeland (life sciences), which is well worth the time if you are really into this topic. It is difficult to add insight to the BioLogos article in this brief blog post, but at least we can express opinions and comment on the issues in general.
It is inevitable that many atheists will assert that the discovery of ET intelligent civilisations would put an end to religion and undermine Scripture. Others claim that since the Bible does not mention life elsewhere, it has nothing to say about the discovery of aliens. But then, as the BioLogos article points out, the Bible does not mention life in Australia either! Indeed, the article points to a survey of people who have a religious faith, which found that, actually, most are happy with the idea of life elsewhere and do not see it as a threat to their beliefs. However, a counter-view is expressed by Robert Lawrence Kuhn in a YouTube video, Would intelligent aliens undermine God?. He suggests that ET life poses challenges to Christian theology, but less so for Eastern religions.
Among the many aspects discussed by Haarsma and her co-presenters, are on the one hand the universality of God’s created order, and on the other what might be called ‘parochial concerns’, those linked to planet Earth, especially related to the assumed uniqueness of humanity. The Christian Bible is truly universal in scope. It speaks not only of the Earth but of the entire Universe. God’s creation is unbounded and includes all worlds, and whatever forms of life that resides upon them.
However, it is the Earth-bound aspects that are of primary concern. Two thousand years ago Jesus Christ lived among us and experienced human existence ‘first-hand’. The incarnation is central to our Christian faith. The obvious question posed by Haarsma is that if God created intelligent beings on other planets, would Christ have been incarnate in those species too? Or is the incarnation unique to Earth? In other words, is the Bible just the ‘local branch book’?
It is a question that has been explored by many authors. In his space trilogy, C. S. Lewis discussed the possibility of intelligent beings who developed a moral code and asked about their relationship with a creator-God. In the Narnia chronicles, Christ is incarnate as a lion, Aslan. The idea here is that God becomes incarnate amongst the created beings in an appropriate form. If that is so and if indeed the Universe is ‘teeming with life’, then is it reasonable to suppose that Christ became incarnate to other civilisations (assuming that abiogenesis can always lead to intelligent life and then to ‘civilisations’) throughout the Universe? For many (but not all) theologians, including C. S. Lewis, the answer is ‘Yes’ (2), while amongst scientists, Christian physicist Russell Stannard says, 'I can't see why the same Son of God, who has existed for all time, can't take on the form of other creatures once they reach the stage where they can communicate with God’ (3).
But actually we have to remain agnostic on this topic, albeit with an inclination to agree with C. S. Lewis and Russell Stannard. We have no idea what intelligent ET beings would look like. We have no concept of how their spirituality would be manifest, assuming that they are spiritual beings, or of how they might relate to God. We can only say ‘God knows’, with no hint or intention of irony. God reminds us of this in the book of Isaiah, when he declares – “ … For my thoughts are not your thoughts, neither are your ways my ways. … As the heavens are higher than the earth, so are my ways higher than your ways and my thoughts than your thoughts.” (4).
One memory for Graham which underlined God’s ‘otherness’ concerned a late evening flight many years ago when he was returning to Southampton from Amsterdam. The flight path skirted the southern part of the conurbation of London, and it was a beautiful clear night. The whole of London stretched out beneath him like a huge, glowing living organism. While taking in this awesome sight, a curious thought suddenly flashed into his head. Just in that one city, at that moment, there was probably several hundred thousand of prayers rising to God. As a Christian who believes in the power and efficacy of prayer, it brought into sharp focus Graham’s complete lack of understanding of God’s omnipotence. The memory spurred him to suspect that, if there is a need to redeem a fallen alien civilisation (presumably, not all of them would be in need of this?), then God would find a way to show his redemptive love.
Finally, it has to be said that there are many scientific and theological questions that remain unanswered (some of which are probably unanswerable) and as a consequence there is currently insufficient knowledge and evidence to determine the existence, or otherwise, of life elsewhere. While it is interesting to ponder these questions, it is also important to worship and serve God here on this planet. In the light of current issues, we need to remember that for us Earthlings, ‘there is no Planet-B’ and that God has asked us to look after this one, ‘Planet-A’, our beautiful Earth.
“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.