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Russell: The Sun and the other stars are great balls of fire. The depths of space, by contrast are freezing cold. The distances involved are immense. The Big Bang that created the universe was unbelievably violent. It's perhaps not surprising that many people view the universe as hostile to life. The physicist Steven Weinberg once dismissed life as 'a more or less farcical outcome of a chain of accidents'. But first impressions can be deceptive. Here are some of the laws of nature, the laws that governed how the cosmos evolved and govern all that goes around us now. It turns out that if these laws had been fixed at random, if the strength of the gravitational force, or the strength of the Electrical force, or the masses of the sub-atomic particles, or the violence of the Big Bang. If any of these had been chosen purely at random - then the chances of having a world with life, any kind of life, would have been virtually zero. So the universe appears to have bent over backwards to accommodate life. This observation goes under the name The Anthropic Principle.As another physicist, Freeman Dyson somewhat colourfully put it: '’The universe knew we were coming' So how are we to account for it - the way the universe is so life-friendly? Was it specifically designed as a home for life by some Creator? That's one possibility. But that, of course, takes us way beyond the realms of science. Some seek to solve the problem by suggesting that our universe might not be alone. There are other universes. Lots of them. Perhaps an infinite number of them. The whole ensemble is called the multiverse. And the idea is that the laws of nature are different in all the individual universes. In the vast majority of them there is no life because one or other of the conditions was not satisfied. But once in a while there comes along a universe which, purely by chance, happens to have the right set of conditions for the development of life. We being a form of life ourselves must, of course, find ourselves in one of these freak universes. Fair enough. That would account for why our universe is life-friendly. But that simply raises another problem: How are we ever to prove that there are universes other than our own and that they are run on different lines?
Other universes, by definition are not part of our universe and so cannot be contacted. So it could be that the multiverse idea might also lie beyond the realms of science When thinking about our universe being life-friendly, one can't help wondering whether there might be other forms of life out there. And if there is life and it's intelligent, how does that affect the status of us humans? Well, as far as our Solar System is concerned, the planets circling our sun, there might be some forms of very primitive life. We should have the answer to that quite soon as a result of planned space probes. But not intelligent life. No, if ET exists it must be on a planet going round some other star, what we call an exoplanet. And there's no shortage of those. Several hundred have been found and the tally increases weekly. Most of them will not be habitable. But from the law of averages, there must be many, many earth-like planets out there, planets where intelligent life could flourish. Which is not to say that it has. So a big question is whether or not there is extraterrestrial intelligent life, and if so what’s it like. Evolution on earth took a very long time, billions of years.
So, on some other planet, it has only to get out of step with what happened here on earth to only a small degree for ET to have reached our level of intelligence, the intelligence of a Charles Darwin, to have reached that level a long, long time ago. So that means they must by now be way ahead of us. Except, except the human race has got this far in intelligence because, in the past there was survival value in having a superior intelligence. You had a better chance of surviving to the point where you could mate and pass on your superior genes. But does that still apply today? Do the more intelligent people today have more children than the less intelligent? If anything, I'd have thought it was the other way round. After all, the more intelligent you are the better your chances of getting a well-paid job. And the better paid job leads to a higher standard of living and the fewer children you are likely to have. If that's true of us, perhaps it's also true of ET. On the other hand, when ET reached our stage of development, it would know all about DNA and genetic engineering. For all we know, they might be heavily into genetically engineering designer babies with superior intelligence, a case of directed evolution rather than relying on evolution by natural selection. In which case as we previously thought, they will now be vastly superior to us. On the other hand, when they reach our stage they discover nuclear power, and in all probability, in a comparatively short time, they blow themselves up.
Perhaps that's the fate of all intelligent species throughout the cosmos. They reach the stage we're at, then POOF! That's it. No further improvement. So, which of these scenarios, if any of them, which of them is right? How can we find out? Simple. Go and visit them, as is done in countless science fiction adventure stories. No. Hardly. The distances are just simply too far. Space travel is not the answer. The other approach is to search the skies for any signals indicating that ET is trying to communicate with us. Such searches have been carried out for many years by the SETI programme - the Search for Extraterrestrial Intelligence. But so far without success. The search will carry on but there's no guarantee that they will find anything. Even if ET exists they might not have the means to communicate with us or the desire to communicate with us. The situation is not under our control. It's up to ET. Perhaps we're destined never to find out about intelligent life elsewhere in the universe?
After Piece
Tony: Russell? Russell, sorry slight problem, page 21 of the script. You say ET might be getting more intelligent when they get affluent. Then you say 'On the other hand they might go in for genetic engineering'. And then you say 'On the other hand they might blow themselves up. That's three hands.
Russell: Well perhaps ET has three hands. You know, it would be very useful as you’re at a reception and you’re trying to eat. It’s all to do with survival value, surviving stand up receptions.
If the laws of nature had been chosen at random, with arbitrary values for the masses of the fundamental sub-atomic particles, the strengths of the forces, the thrust of the Big Bang and so on, the chances of life being able to develop anywhere within the universe would have been virtually zero. The life-friendly nature of the universe goes under the name The Anthropic Principle.
So, why is it thus? Was it deliberately designed that way? Or are there many universes, all running on different lines, with ourselves living in a freak universe that happens, purely by chance, to have all the right set of conditions? The latter possibility is known as the multiverse. But how could we ever hope to verify the multiverse hypothesis if we can only make contact with whatever is in our own universe?
Given that there must be many locations in the cosmos where life could have developed, we ask whether there are extraterrestrial forms of intelligent life. If so, how advanced are they likely to be? And what are our chances of ever finding out about them?
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ET, life and the universe
So, on some other planet, it has only to get out of step with what happened here on earth to only a small degree for ET to have reached our level of intelligence, the intelligence of a Charles Darwin, to have reached that level a long, long time ago.
I think "get out of step" perhaps gives a false impression, implying that the steps started together. The Sun and our Earth were formed around 4.5 billion years ago but star formation probably started at double that age. Evolving no faster than our planet, there could still have been intelligent species in existence before our Sun even formed.
So, which of these scenarios, if any of them, which of them is right? How can we find out? Simple. Go and visit them, as is done in countless science fiction adventure stories. No. Hardly. The distances are just simply too far. Space travel is not the answer.
This doesn't take account of the timescales involved. Studies of hypothetical solar sail missions to the Oort Cloud (see "Technology Requirements of Exploration beyond Neptune by Solar Sail Propulsion" by Macdonald, McInnes & Hughes) suggest advanced technlogy is required to provide mission durations of the order of a century while credible developments of existing materials result in times of a few centuries to the nearest stars (400 years to 200,000 AU). However, such speeds still mean a system of self-replicating probes (as suggested by e.g. Freitas) could span the galaxy in less than 15 million years. That may be a long time by normal standards but it must be compared with times of the order of 1 to 4 billion years between the arising of technological species if there are less than a dozen extant.
The other approach is to search the skies for any signals indicating that ET is trying to communicate with us. Such searches have been carried out for many years by the SETI programme - the Search for Extraterrestrial Intelligence. But so far without success. The search will carry on but there's no guarantee that they will find anything. Even if ET exists they might not have the means to communicate with us or the desire to communicate with us.
Or perhaps they tried that for a few million years but gave up 5 billion years ago, just before the Sun formed.
All this of course is only considering ET technological civilisations, SETI will only find those capable of targeting us with a powerful radio beacon (and choosing to do so). To find life in general, a much better solution would be the New Worlds Imager project which could detect the spectrographic signs of life in extrasolar planetary atmospheres.
The situation is not under our control. It's up to ET. Perhaps we're destined never to find out about intelligent life elsewhere in the universe?
On the other hand, if we decide to "go and look", it is under our control. It may take millions of years, but that is the blink of an eye in astronomical terms. We could probably launch the first probe of such a scheme within this century and since the system has to be autonomous since we cannot remotely control devices on the other side of the galaxy with round-trip signal times of tens of thousands of years (20 minutes to Mars proved difficult for NASA) after the first is launched, it doesn't even matter if the human race becomes exinct, the probes would continue long after our disappearance.
George