A desolate place to look for answers : SCIENCE

The meaning of life in our universe is not as perplexing as it is depressing, says Peter Atkins

Science is often accused of failing to tackle the great questions of existence and, instead, of spending its time plucking wings off butterflies. That is a false accusation, for in its careful edging forward, science offers knowledge that elucidat es ourcosmic role more convincingly than millennia of armchair and tribal speculation.

I consider there to be four principal questions of existence. Where did it all come from? Where is it all going? How is it getting there? What is it all for? Others will no doubt add to this list, perhaps pointing at the problem of our awareness of the world. They might worry about evil, the existence of a soul, or the prospect of personal annihilation. But however intrinsically interesting such issues are, because all but consciousness are invented tribulations, they are not truly deep questions about the cosmos.

Science tackles the first of the great questions - where did it all come from? - by trying first to assess what there is. One of its achievements has been to show that the world is in fact exceptionally simple. A straightforward technique for discoveringwhat makes up the world is to heat matter until it falls apart, and then to examine the fragments. This technique is readily applied to flimsy molecules (as we do every day in the kitchen), but very high temperatures are needed to break elementary particles into bits. Nature, however, provides a suitable oven.

As the universe has expanded, it has cooled; so, by tracing the universe back in time, we also trace it up in temperature. As we do so, we find that seemingly sturdy particles fall apart, and in the earliest moments of the universe we find that only verysimple, perhaps structureless, particles survive. In short, the universe can be dismantled into half a dozen kinds of elementary particles. As the universe has cooled, these particles have been able to cohere into ever more elaborate structures, and thepresent temperate universe allows structures as elaborate as organisms to survive.

We are already confident about the history of the universe back to one-trillionth of a second (10-12s) after its inception.There is good circumstantial evidence, and some observational evidence, for events that took place much earlier, when the universe was about 10-35 seconds old. It is increasingly widely believed that at that time the universe underwent an extraordinary expansion in which it doubled its size in 10-35seconds then doubled it again, and again every 10-35seconds until suddenly, when the universe was a hundred times older (but still only 10-33 seconds old), the inflation stopped. By then, though, it might have expanded by a factor of up to 10 multiplied by itself a trillion times.

If the inflationary scenario is correct, it has extraordinary implications. First, the visible universe (all we can ever hope to see, with light taking the age of the universe to reach us) is but a minute fraction of the entire universe. Even more humiliating, it may be that inflation has occurred in many places, and the universe is like a foam of bubbles, with our visible universe an insignificant dot somewhere in one of these bubbles. It is even possible inflation is still occurring somewhere, or everywhere, or will begin again. There could be an infinite number of bubbles, with the number increasing at an infinitely accelerating rate. Could there ever be a bigger thought accompanied by a greater diminution of human significance?

This still does not answer the question as to what there was before there was anything at all. One possibility is that there was nothing at all, and what there is is simply an engaging reorganisation of nothing. We know that the universe has zero electric charge, but there are positive and negative particles: so charge was not created at the creation, just separated into opposites. We know that the universe does not rotate overall, but that things in it do rotate in opposite directions. So r otation wasnot created, just separated. There is also a way of adding up all the energy and matter in the universe that strongly suggests there is no net energy either, so energy (and matter, which is essentially the same thing) did not have to be made, but just separated.

So, all a creator had to do was to rearrange nothing. This suggest that science might one day show that the universe simply dropped out of nothing and that nothing had to be created. Reorganising nothing seems to me to be a much less demanding task than creating something.

How is it getting to wherever it is going? This is where that great liberator of the human spirit, the Second Law of Thermodynamics, illuminates our understanding. The essence of this is that things happen naturally in the direction that increases disorder in the universe. All natural events, including those that result in works of art and the mental events involved in their appreciation, are driven by purposeless decay into corruption. It may be a bleak view of the world, but there it is.

And where is it going? Well, in about 7 billion years the Sun, our life-giver, will have consumed its children, and the Earth will be a cinder in orbit. Unless we manage to escape before that happens, there will be no relic of our aspirations. Looking rather further into the future, we still have to contend with the decay of matter. It is quite likely that protons, the heavy part of matter, will decay into positrons in something over 1012 years' time, and all we shall have of our cities and colonised pl anets will be electrons and positrons. Eventually these, too, will collapse into radiation.

Radiation is not much help in the avoidance of doom. As the universe expands, so it stretches any waves it contains. In due course, all the radiation into which we and our constructions and memories have collapsed will be stretched out into dead, flat spacetime. That's it: all gone. The only difference between the beginning and end of time is that initially there was nothing - not even space and time - and finally there will be utterly dead, empty and desolate spacetime.

In relation to my questions, therefore, I would like to suggest the following answers. Where did it come from? From nothing. Where is it going? To oblivion. How is it getting there? By purposeless decay into chaos. And the cosmic purpose? I leave you to draw your own conclusion.

The writer is a Fellow of Lincoln College Oxford and the author of `The Creation' and `The Creation Revisited'.