Saturday 21 April, 2001
Vital Clues
By all the laws of chance, we shouldn't be here. If any one of more than a dozen different fundamental properties of the universe did not have the precise values that they do, complex systems such as life on earth would never develop. Scientists and philosophers tend to be sharply divided over the significance of this.
In Living Universe, series producer Martin Redfern asks why are we on earth and can a universe reproduce.
Some scientists explain our existence simply: we are just a random accident. Others say there must be not one but an infinite number of universes, most of them dull and sterile. A third and smaller group find something mystical, almost religious in the coincidences that have led up to life on earth. They say that in some strange way, there must be a reason why we are here. So what's the evidence?
It now seems clear that our universe began in a hot fireball known as the big bang. That was smooth and almost featureless but it had just enough structure in it to lay down the seeds of the largest structures we see today, clusters of galaxies hundreds of millions of light years across.
For the first few seconds, it was a mathematicians universe. Everything could be explained and understood in terms of simple laws. To physicists, it was neat and orderly.
A Messy Universe
By comparison, the universe today is a mess. Had it persisted, that physicists' universe would have been very dull indeed, with uniform clouds of gas and no galaxies, stars, planets or life. It is the mess that we call home.
The last 12 billion years of history have seen the steady enrichment and an increasing complexity to the universe. The mechanism by which complexity develops has become a whole new branch of science and is being used to help scientists understand everything from earthquakes and volcanoes to economics and history.
Key To Complexity: Atoms
One of the keys to complexity seems to lie in the nature of the building blocks of the universe - the atoms. Just as in a child's construction set, the pieces can be joined together in many different ways. Were the building blocks more simple, nothing much would happen.
As Craig Hogan, at the University of Washington, explains:
| 'If you play with Lego, there are certain kinds of blocks that you can not do much with, you can't make anything complicated. Nature seems to be like the full Lego kit…you can build arbitrarily complex things.' |
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As it is, we have building blocks such as carbon, nitrogen and oxygen which can link together to form the molecules of life including the spiral of DNA that holds the blueprint of our bodies.
It turns out that so all this complexity is the result of the values of certain fundamental constants of nature. These include the strengths of the forces that hold the nuclei of atoms together and the rather different strengths of the electromagnetic force and of gravity. If the ratios of these were slightly different, stars would either never form or would not be able to create the elements of life such as carbon and oxygen within them.
If some of the stars didn't blow up, they wouldn't scatter those elements into clouds from which planets could form. If stars burned up too quickly, there would never be a chance for life to develop on those planets and if the stars did not shine reasonably constantly, the climate would never be right.
As yet, the physicists know of no fundamental reason other than our own existence, while those key constants should have the values they do, so for the moment, the next stage is a matter of belief.
Some scientists, referred to by their colleagues as macho physicists, think that science will eventually explain everything and that they will be able to find a reason in mathematics for the values of the constants. Others say that this itself seems more like religion than science because, if it were true, then the universe really is fine-tuned for the production of life.
The Multiverse
So they suggest that perhaps there can be many different values for the constants and that we live in a sort of foam of many universes. They call it the multiverse. Once all those possibilities exist, it is no longer surprising that we inhabit a world that is right for life, any more than it is surprising that we live on the surface of a hospitable planet rather than in the cold darkness of space or the searing heat of a star.
Douglas Adams, author of the Hitch-Hikers Guide to the Galaxy, emphasises the point by describing what he calls puddle theory.
| After it rains, puddles of water are totally amazed by the fact that there should be holes in the road exactly the same shapes as they are. We of course think that silly because we know that they were moulded to fit the holes that existed anyway. So it may be with universes. |
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It must be quite fun to be a cosmologist, because when one is speculating about something far beyond our own universe and beyond anything one could ever see, it's impossible to see how one could ever be proved wrong. And that is why some people find it easier to believe that there is something special about the world one can see, something which makes us special too, rather than believe in a multitude of worlds out there.
|  |  | | | Famous Question |  |
| | 'Did God have any choice in the creation of the Universe?'
Albert Einstein
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| | | | UFO Activity |  |
| | Project Phoenix is the world's most comprehensive search for advanced intelligent life.
It is a non-profit, privately funded venture, run by the Seti Institute in California, USA.
It employs a large radio telescope installed at Arecibo, Puerto Rico. It picks up radio signals and information produced by technology, which is deliberately or mistakenly beamed by, say, other planets.
The telescope measures 140 feet and is pointed at terrestrial-like planets around some 1000 nearby stars.
Jill Tartar, at the Seti Institute in California, explains:
'What we'd really like to see in order to infer the presence of life on another planet is the co-existence of very reactive molecules…methane and molecular oxygen.'
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