Self-replicating?

What brings DNA to life, what gives it meaning, is the cellular environment in which it is embedded... Genetic theorists with little biochemical understanding have been profoundly misled by the metaphors that Crick provided in describing DNA (and RNA) as 'self-replicating' molecules or replicators, as if they could do it all by themselves. But they aren't and they can't... You may leave DNA or RNA for as long as you like in a test-tube and they will remain inert: they certainly won't make copies of themselves... The functioning cell, as a unit, constrains the properties of it's individual components. The whole has primacy over its parts

Steven Rose, Lifelines: Biology, Freedom, Determinism
As quoted by Mary Midgley

Walking the Planck

Max Planck, a German physicist who died in 1947, is regarded as one of the fathers of Quantum Theory – the branch of physics which deals with the tiniest packets of matter that have a kind of dual personality, behaving like both a wave and a particle. Its an intriguing world where nothing is certain and some things are impossible to measure.

Bearing his name is the concept of the 'Planck length'. This minute distance is the length at which we enter the quantum world and therefore is the smallest measure of length that actually means anything. Below this distance space, time, gravity and all of conventional physics dissolve away.

Following on from this is the 'Planck time'. This is the length of time it would take a photon of light to travel the 'Planck length' – and its 10 to the power of -43 seconds! In a similar way to the Planck Length any time less than this is effectively meaningless, for the reasons given above.

The Planck time has deep philosophical implications. It means that the Universe effectively 'began' at this age, this is actually when time began. It also means that we cannot be sure of anything that happened 'before'*. Therefore, any world view that depends on determining what might have occurred prior to the Plank Time is on very shaky ground.


* NB Even the word 'before' is inappropriate here. Its like asking whats south of the South Pole!

Lego DNA

The problems with trying to piece together a plausible mechanism for the origin of life multiply up. Its not just about thinking up possible scenarios where the various complicated molecules could be manufactured and thrown together. Scientists also have envisage a scheme that explains the origin of the whole system of genetic information with its unique language, replicating systems, translation devices.

This video provides a great animated version of what some of that entails. Looks like Lego DNA to me!

Life out of death

Perhaps Agatha Christie would have been intrigued by this piece of new research.

The chemistry of life revolves around six key chemicals. Carbon, oxygen, hydrogen, nitrogen, phosphorus and sulphur make up the major ingredients of many of our body's building materials.

However, from the bottom of a lake in California comes a bacteria that uses arsenic as a substitute for phosphorus. Arsenic has a similar size and charge to phosphorus which makes the switch possible and this in turn presents interesting discussion points. If phosphorus can be substituted then what else? Could there be an entirely different system of life out there based on different elements?

Whilst this is a genuinely novel discovery it is unlikely that it can be extended so far. For a start even this finding has its limits:

It is thought that downstream metabolic processes are generally not compatible with As-incorporating molecules because of differences in the reactivities of P- and As-compounds. These downstream biochemical pathways may require the more chemically stable P-based metabolites

This microbe probably represents the outer fringes of what makes up the biosphere, rather than the doorway into another world of possibilities.

Another gap closed?

I just bought a copy of The Times for the first time in months - so it worked!

The current commotion is all about pre-release comments from Prof Stephen Hawking, author of an upcoming book The Grand Design. What has he said?

Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going.

We'll have to wait until the book is published to find out the full story, but essentially we're talking about origins, origins of the universe and the Big Bang. The religious problem exists for people whose belief in God is fuelled by things that science can't explain - the gaps. However, before the atheists get too excited, for many believers this just isn't the way they understand God.

God is not squeezed inbetween like intellectual Polyfiller, rather he is the potter who shapes the Universe he created. In a way that means that there shouldn't be any gaps. As Dr David Wilkinson, astrophysicist and theologian, said today

The God Christians believe in is a God who is intimately involved with every moment of the universe's history, not just its beginnings

Hawking concluded his previous book by saying that if we could unify the physics of the Big Bang we should 'know the mind of God', and perhaps this next work will be his answer, but one thing is for sure: God's mind is not deciphered entirely by equations. However revealing they may be, there is a limit to the efficacy of science in this domain. Dr Lee Rayfield, Bishop of Swindon, put it like this

His conclusion does not change the remarkable coherence between the nature of our universe and the understanding Christians have about the nature and character of God.

Still, the storm in a teacup will continue for at least as long as The Times' serialisation goes on. Dawkins will continue to buzz like a high energy particle at straw men and soft targets, but the real loser will be truth. Some people will be turned off science by the comments, others religion. What a shame. As theoretical physicist Prof Chris Isham lamented...

I groaned when I read this. Stephen's always saying this sort of thing - he loves the publicity.

And I'll be buying the book on the back of it. Sucked in!

The Weak Anthropic Principle

Barrow and Tipler offer this definition:

"The observed values of all physical and cosmological quantities are not equally probable but they take on values restricted by the requirement that there exist sites where carbon-based life can evolve and by the requirement that the Universe be old enough for it to have already done so"

Here's an example.

We observe that we exist at a point in the life of the universe where carbon is readily available (it wasn't this way earlier on).

But then this would have to be so - because if there wasn't any carbon then there wouldn't be any us.

The Anthropic Principle

In the perspective of these violences of matter and field, of these ranges of heat and pressure, of these reaches of space and time, is not man an unimportant bit of dust on an unimportant planet in an unimportant galaxy in an unimportant region somewhere in vastness of space?

No! The philosopher of old was right! Meaning is important, is even central. It is not only that man is adapted to the universe. The universe is adapted to man. Imagine a universe in which one or another of the fundamental dimensionless constants of physics is altered by a few percent one way or the other? Man could never come into being in such a universe. That is the central point of the anthropic principle. According to this principle, a life-giving factor lies at the centre of the whole machinery and design the world.

John A Wheeler's Foreword to 'The anthropic cosmological principle' by John Barrow and Frank Tipler

Playing god

Craig Venter's work has hit the headlines again. Its exciting stuff, but rather than going into the ethical issues that present from the first synthetic species created I want to pick up on what it means for the study of abiogenesis (origin of life).

A few years ago Venter's team produced the simplest form of life they could possibly manage by cutting bits out of the genome of a very simple bacteria. They kept on cutting bits out until they got to the point where if they lost any more genes then the cell just wasn't functional. The end result was a bacterium with a genome of around 500,000 base pairs. You could think of it as the lowest common denominator of life.

Now the team have stitched together a completely novel genome from scratch, but here's an interesting extract from an interview with Dr Venter:

How difficult was this?

At one time there was just one error in over a million base pairs, and we found that as a result you don't get life.

In explaining how complex a task it was Venter explains that anything worse than 99.9999% fidelity just doesn't work. That's astonishing. And when you combine it with the previous findings outlined above you realise that at root life is an exceptionally special and delicate phenomenon.

Aluminium Clocks

Isotopes are one of the main methods of dating materials. Just one example is Aluminium - which exists in the 2 isotopes of Al-27 and Al-26.

The idea is quite simple. In the beginning you start off with Al-27 but gradually over time this becomes Al-26. The rate at which this happens is constant, so if you measure the relative amounts of the 2 isotopes then you have a good idea of how old the sample is.

Aluminium is more complicated because Al-26 actually then decays to Mg-26 (with a half life of 0.73 million years), but evidence from chondrites (the most common form of meteorite) suggests that Aluminium was found consistently around our solar system in its early days (at a ratio of 10%). This is important because it confirms that it is useful as a chronometer.

In turn we can again be confident that our universe is indeed very, very old.

In spite of all this...

Tempting though it is to look at animal behaviour and make it human, the comparison may not always be accurate. The problem is, for example, how can we really know what’s going on behind those big dark eyes of man’s best friend?

Having said that some examples nicely illustrate how human morality is so different to anything else in the animal kingdom. A recent study of Chimpanzees highlights this.

The idea of ‘punishment’ is important in social groups because it is an aid to cooperation. If bad behaviour is punished then good behaviour, that helps the group, is encouraged. This might look like morality but at root it’s just a sophisticated form of selfish protectionism.

‘Spite’ is something different. Spite is just punishment for the sake of it i.e. without any positive outcome attached to it.

In this study one chimpanzee was given access to food whilst another chimpanzee had no access to it but instead was able to reach a rope that knocked over the table of food and took it away from both of them. After setting up some suitable controls the researchers found that the chimps didn’t knock the food over out of spite. They then did a second study where the second chimp was allowed to have some of the food before it was given to the first. When the chimp perceived there being a theft they were quick to pull the rope and punish the bad behaviour.

The conclusion? Whilst chimps can be vengeful and punish anti-social behaviour they are not spiteful. This is a peculiarly human behaviour.

Humans are alone in having the freedom to think about and choose our behaviours. We use this freedom for better and for worse, for good and for evil. We are quite willing to act spitefully – even at a cost to ourselves – but thankfully we are also willing to give at a cost too. The choice is ours. The inspiration is Christ.

Eternity in our hearts

There are plenty of creatures out there that have a sense of time. You only have to look at the seasonal migration patterns of birds such as the Swallow to realise that. But we humans are unique in the way that we use time. We have daily schedules, long term plans, a fascination with history, and a sense of eternity.

He has made everything beautiful in its time. Also, he has put eternity into man's heart’
Ecclesiastes 3 v 11

Our sense of time relies heavily on our ability to use language. To that extent the Piraha tribe from Brazil are very interesting. Their language has no numbers! It also doesn’t have a perfect tense (e.g. I have gone...) The way their language is structured thus translates into their culture. They only have a very shallow knowledge of their own history (no more than two generations) and there are no creation myths or similar such legends. As a people they live very much in the present.

So our sense of eternity is in part due to our language abilities. It’s also got a lot to do with maturity. A recent study confirmed what everyone probably knew already and that is that it isn't until we get to our late teens that we really start thinking outside of the moment and realise the long-term implications of our actions. Compared to adults, adolescents are less future orientated and less likely to plan for the future. What's fascinating is that the areas of the brain associated with foresight and planning continue developing through into the mid-20s.

From a faith point of view our far-sighted brains and erudite language combine to allow us to begin to comprehend eternity. The Bible says that eternity is why we're here in the first place!

On the origin of life...

Why is it that anytime even a *hint* of a drop of water is found anywhere else in space there are loud cries of 'Life!' to accompany it? Is it anything to do with research budgets?

The latest example spotted by NASA is Enceladus, a tiny moon orbiting Saturn.  Let's be fair though, if they're right then this is more than just a drop - its a whole subterranean ocean.  The BBC report has the following quote:

"We need three ingredients for life, as far as we know - liquid water, energy and the basic chemical building blocks - and we seem to have all three at Enceladus, including some fairly complex organic molecules," commented John Spencer, a Cassini scientist from the Southwest Research Institute, Boulder, Colorado.

Now don't get me wrong, this is an exciting find, but the one thing that has been learnt in the study of abiogenesis so far is that it is far from straightforward.  The search is still on for how to get to 'first base'  and gather all the necessary basic ingredients.  A very recent suggestion is Titan, another one of Saturn's satellites.  It has an atmosphere made from Nitrogen and Methane giving traces of other simple organic compounds.  So maybe the basic chemicals were synthesized there and came to Earth on the No 42 meteorite?

I'm not saying a natural mechanism for life's origin will never be found but if it is I'll wager it will be very intricate, very coincidental and very unlikely... almost to the point of being unbelievable.