Guest Post: Building a habitable planet

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NASA

‘How to build a habitable planet’ is the title of a popular American college textbook which tells the story of the Earth from ‘The big bang to humankind’. It’s a big book – because it is a long story. All the evidence we have suggests that in its infancy the Earth was a most inhospitable planet and not very different from its near neighbours. Back then it had a transient volcanic landscape, a carbon-dioxide-rich greenhouse atmosphere and was periodically bombarded with asteroids from space. In contrast today we see a planet with mobile tectonic plates, oceans, continents, an oxygenic atmosphere and teeming with life, fundamentally different from Mercury, Mars or Venus. So, why? What is it about the history of the Earth which makes it so different now from its near neighbours? Continue reading

Two Ways to Truth

Photo from Test of FAITH. © The Faraday Institute
Photo from Test of FAITH. © The Faraday Institute

Many of us have looked up at the night sky and felt a sense of awe and wonder before the universe. This experience made Revd Dr Rodney Holder, former Course Director at the Faraday Institute, want to be an astronomer from about the age of seven. Here, he reflects on his work as an astrophysicist and how that connects with his faith.

Nowadays, because there is so much light pollution in Britain, I most often get that feeling of awe and wonder when I’m on holiday. A few years ago my wife and I were in Croatia, staying in a small hamlet, and on balmy nights we sat out on our balcony and gazed up at the sky, counting shooting stars. On another holiday we were in Peru, high up in the Andes, when we saw the night sky of the Southern hemisphere in all its glory for the first time.

The writer of the Psalms must have Continue reading

Symmetry or fine-tuning?

Hydrogen_Density_Plots, public domain

Why is there so much symmetry in nature? I shared some examples in an earlier post, and questioned whether there was a link between these and the ‘fine-tuning’ of the universe. I asked Francesca Day, a PhD student at the University of Oxford, if she could investigate. Francesca’s own work is on the astrophysical signatures of dark radiation, and here she explains why she thinks symmetry might lead to a more wonderful explanation of the universe than the mystery of fine-tuning.

Many argue that if the laws of physics had been just slightly different, life – or at least life as we know it – would not have been possible in the universe. The fundamental laws and parameters of physics seem to have conspired so as to make the formation of life possible. To many it seems as if science is pointing to a designer of the universe who set all these parameters just right for us – as if science is pointing the way to God. Continue reading

Symmetry

Hurul Ain, www.freeimages.com
© Hurul Ain, http://www.freeimages.com

Why is there so much symmetry in the world? Sea urchins, jellyfish and other animals that sit still or float around gently have radial or rotational symmetry, so they look the same if they are rotated around a central axis. All other animals – the ones that move around – have bilateral or mirror-image symmetry.*

Flowers often have rotational symmetry, and most leaves have approximately bilateral symmetry. Five-fold symmetry is found in both plants (for an example, cut an apple in half across the core) and animals.

Symmetry can be seen in astronomy, and it is also important in chemistry – biological systems which use a specific molecule often cannot use its mirror-image. We find symmetry attractive, and people we think are good-looking tend to have very symmetrical faces.

So what lies at the root of these phenomena? Continue reading

Predictable Universe?

Two planets. Gilderm, http://www.sxc.hu/
Two planets. © Gilderm, http://www.sxc.hu/

Over the last few years, the universe has started to look increasingly friendly to life, and scientists who previously said they didn’t expect to find living things on other planets are beginning to change their tune. NASA’s Kepler telescope may be largely non-functional, but the search for other organisms in the Universe is just beginning.

Last month at the Faraday Institute, astrobiologist Stephen Freeland gave a lecture entitled, ‘Will alien life share our genetic code?’ – a topic which would have been on the border of science fiction a couple of decades ago, but is now a serious question. Continue reading

Biological Fine-Tuning

© Sharlene Jackson, freeimages.com

It’s reasonably common to hear physicists and astronomers talk about ‘fine-tuning’, or the ‘anthropic principle’. The idea is that a large number of physical properties (such as the strength of gravity, or the forces within the atom) need to be at very, very precise values or life as we know it would not exist. The numbers are incredible – probabilities with more decimal places than there are atoms in the universe!

Is there any evidence of fine-tuning in biology? Biology is a much newer science than astronomy and the systems involved are far more complex, but even so, there are a few glimmerings of fine-tuning on the biological horizon. There has been a good deal of interest in Cambridge Palaeobiology Professor Simon Conway Morris’s research on convergent evolution. In his popular level book, ‘Life’s Solution: Inevitable Humans in a Lonely Universe’ (CUP, 2003), he describes how the course of evolution navigates towards fixed points in the total space of biological possibilities. This winding path towards higher levels of complexity, and ultimately intelligent life, is entirely consistent with the Christian belief in the purposeful sustaining of the universe by its Creator.

So has anyone else approached the subject of fine-tuning in biology, or is Conway Morris a lone voice? Theologian and biochemist Alister McGrath has spent time on this subject (see A Fine-Tuned Universe and a less technical reworking of similar material in Surprised by Meaning). The main point McGrath makes is that the biological world relies on the same fine-tuned physical and chemical properties that astronomers spend so much time discussing.  Without compounds such as carbon, oxygen, hydrogen and phosphorus, life simply wouldn’t exist.

McGrath also points to an interesting paper in the April 2003 issue of the International Journal of Astrobiology. In it, astronomers Bernard Carr (St Mary’s, London) and Martin Rees (Cambridge) give an account of a 2002 conference on biological aspects of the anthropic principle. Even in a conference with this title, issues of chemical evolution took up part of the proceedings, but what was most interesting was the section on ‘evolution of biological fine-tuning’. The research in this area was all too tentative to be published more fully, but covered areas such as robustness in biological networks, and the ‘choice’ of DNA and proteins as information carrying molecules in biological systems.

Biological systems are enormously complex, which is why it’s taken us so long to get around to even beginning to understand things at the level of whole organisms. But there is a trend, in that although the total ‘space’ of possibilities (for example, for the sequence of a protein of a particular length) is usually enormous, in reality the number of variants present in nature is relatively small. At times it is possible to pinpoint why certain solutions have been arrived at – for example, the camera eye is quite simply the best way to see light. At other times the reason why a particular solution has been arrived at is less clear, as in the origin of biochemical systems and cellular life.  Whether the existing systems we see are an accident of history (i.e. where a number of potential solutions could work) or are another example of fine-tuning, is yet to be determined. What is clear to me, however, is that the astonishingly fertile chemistry of life and evolvability that we see is entirely consistent with the existence of the God revealed in the Bible who provides us with a rich source of teaching and guides us though the process of learning by our mistakes.