Dr Kathy Sykes is a science communicator. Her background is in physics and she spends her time making science interesting for everyone either by giving talks and writing or by creating new exhibitions and science festivals.
So is there intelligent life out there?
What a great question. It fundamentally affects the way we see ourselves – yet we really don’t know the answer.
One way to tackle the issue is to break the problem down into manageable ideas. So you can start off with easier questions like: ‘what are the chances of there being stars like our sun?’ or ‘the chances of other planets being earth-like?’. That’s what the Drake equation, featured in the programme, does so elegantly.
For one aspect: ‘is there any life out there?' - I’m pretty sure answer must be 'yes'. ‘Life’ is so damned determined. Wherever there’s water on Earth – in liquid form, at a temperature within a reasonable range – life manages to eke out an existence; from bacteria discovered living underneath metres of Antarctic ice, to creatures that survive several kilometres below the sea’s surface. And just about as soon as life was feasible on Earth around three billion years ago – it began.
So all a planet probably needs is a bit of liquid water in places where there’s a reasonable range of temperatures. We’ve already managed to find over 60 other planets in our own galaxy. And then there are the billions of galaxies beyond ours. Surely some of those other planets have suitable conditions.
Another question I think matters is ‘what counts as intelligent’? The Drake equation looks at our chances of finding a civilisation that’s learned to use radio waves. But I’d be interested in finding other forms of intelligent beings too. Like the late Douglas Adams, I’d count dolphins as intelligent, splashing around having fun in the sea, rather than dashing around like the maniacs humans must seem. But dolphins left to their own devices may never end up developing radio astronomy. They may just find ways of having more fun swimming about. But if we were in a distant galaxy, how could we ever detect dolphins on Earth?
The idea that ‘if we haven’t found anything yet – there probably isn’t anything out there’ is also known as Fermi’s Paradox. Apparently, a load of physicists having coffee were discussing this very issue, and Fermi commented ‘So if they exist where are they?’
But it may not be so surprising that we don’t see evidence of aliens, even if they do exist. The aliens probably have to choose to send out messages if we’re to have a hope of detecting them.
After all, we’re capable of sending messages, but do we actually choose to do it? So far, we’ve just sent out a single message – a radio wave – from the radio telescope Arecibo in 1974. It was directed to a particular part of the sky, the Hercules cluster. There was a big debate at the time about the wisdom of this. After all, we might be colonised, and from experience here on Earth, that never seems to end up being much fun. So, although more messages may have been planned, only one message was ever sent.
But if anything out there were able to detect this, what would they make of it? Would they be listening at the right time in the right part of the sky anyway? If so, could they translate it? And would they take it seriously? After all, a proper scientific approach needs reproducibility. Just imagine, a scientist here makes a one-off detection of aliens: we’d probably say they were barking.
Finally, if the signal we sent was recorded, interpreted and understood, what would these aliens think of us when we just sent out a single signal, then fell silent? After all, anyone intelligent trying to communicate would surely decide to do it, then try quite hard to do it well? So maybe they all know about us, but think we’re indecisive, not too sophisticated and probably not worth talking to anyway.
So - I think there probably is intelligent life out there. Whether it thinks we’re intelligent or not, is up for grabs.
Ian Morison works on the SETI (Search for Extra-terrestrial Intelligence) project at Jodrell Bank Observatory, part of the University of Manchester. He believes that the Galaxy is teaming with extra-terrestrial intelligence - it's just a question of finding it.
What is SETI?
SETI stands for the Search for Extra-Terrestrial Intelligence. It began way back in 1959 when two Americans realised that with a large telescope it would be possible, given another one somewhere out there in space, to communicate between the stars. They therefore suggested that one should perhaps listen in case another civilisation out there were trying to communicate with us. The first observations were made the following year, in 1960. The programme was at one stage run by NASA, but there were sadly forced to withdraw their funding by the US Congress so it was taken over and is now privately funded by a number of rich Americans.
What are you looking for?
The SETI search we’re involved in is a targeted search, that is, we’re looking at those places where we hope the chance of finding another civilisation is highest. Now, that essentially means we’re looking at stars somewhat similar to our Sun, we call them ‘sun-like stars’. These live a long time, which would allow a civilisation to evolve, and they’re hot enough to give a reasonable chance that a planet similar to our Earth might be at the right sort of distance from that star to have the right sort of temperature. In the first instance, we’re looking for very, very simple signals - perhaps the best example I could give you is Morse Code. We’re not looking for television pictures or even sound initially, but something that would take a long time for a message to come, but could be picked up over great distances. We’re currently here using radio telescopes to look for radio signals, other scientists are using optical telescopes now to look for optical signals, in the hope perhaps that there might be somebody out there sending a signal towards us.
Are you sure there are other intelligent civilisations in the Universe?
I must say yes to that. Firstly, I’m sure that very simple life is going to be incredibly widespread. It seemed to happen here on Earth virtually the instant that conditions were suitable. Now, whether it originally arose on Earth or came from outside is another matter, but I’m quite sure that very simple life is very, very common. On the other hand, I don’t suspect that that simple life will evolve into advanced civilisations like ours very often - you need to have a very stable environment for a very long time. There are a number of factors about the Earth which have helped that to happen – the plate tectonic system recycles the CO2, helps to regulate the temperature, the fact we have a large moon has helped to stabilise the Earth’s rotation axis, so you haven’t got the point where one pole might be pointed at the sun, so one half’s very hot, the other half’s very cold. There are a number of things like that. But that is bound to happen somewhere else.
If you take our galaxy, you have a hundred thousand million stars, I would at least hope it’s happened a few times, and maybe many thousands of times. If you take the Universe as a whole, where even just the part we can see has hundreds of thousands of millions of galaxies it must be true. But sadly, I don’t think there’s any way we could ever come into contact with other civilisations beyond our galaxy very easily, so really we have to look within the galaxy. I’m just keeping my fingers crossed.
How optimistic are you that we might pick up a signal?
Well I have to say I’m a realist, I think the chances at the present time are relatively low. But the technology is improving all the time and at the moment new, bigger telescopes are being designed and actually funded, some of that by Microsoft founder Paul Allen. And that will mean that as time goes by the searches will become more extensive and then the chances will get greater. In fact, a colleague of mine working at the SETI institute predicted that contact might be made around the year 2020 on the basis that if you take Moore’s law, which shows how computer power increases every 18 months or so, that’s more or less been applied to the number of stars we can investigate for intelligent signals. If that continues in the same way, then around the 2020 mark we might be looking at a fair percentage of our whole galaxy.
If you did receive a signal, how would you be able to tell it came from another planet rather than from Earth?
Well, that’s actually part of the system in Project Phoenix that we’re working on – we use two telescopes simultaneously, the telescope at Arecibo in Puerto Rico and the one here at Jodrell Bank. Because they are well separated on the Earth, we will not in fact pick up signals that are generated locally to either telescope, and also because the Earth is rotating we have a very nice technique using the doplar shift of signals to prove that any signal we pick up simultaneously is actually coming from outside our solar system. Secondly, the type of signal would be, we think, very specific and rather unlike most signals that are produced by transmitters on Earth, because it would be specifically designed to be picked up over great distances. We know what we would do if we wanted to communicate with someone 100 or 200 light years away, we assume that if they’re trying to communicate with us they’ll do the same thing.
Is SETI still worthwhile, in spite of the fact that it has so far been unsuccessful?
First of all, although the chance of success is very, very low, if we were successful the results would be so fantastic it would be worth it – a long shot is sometimes worth playing if the benefits of success are very large. So that’s one thing. But also I think it’s a lovely subject and it’s amazing how much the public are interested in it, and it’s a way of conveying to people at large about some of the mysteries of the universe, the things that you need to have for life to exist. So it gives a sort of a forum to discuss life and our existence here on our own planet, which could be of benefit to our own human race in the future. So I certainly believe it’s worth doing.
Professor Michael Rowan-Robinson is an astrophysicist at Imperial College, London. Professor Rowan-Robinson believes that the only place to find intelligent civilisation in the Galaxy is here on Earth. If it did exist elsewhere, we'd know about it by now.
Is there anyone else out there in the Universe?
I take the view that we’re perhaps alone in our galaxy, that we are the only civilisation with advanced technology and this is somewhat unusual amongst my astronomical colleagues - most of them take the view that life is common throughout the galaxy and that intelligent life is common.
Could you explain why you are sceptical, with reference to the Drake equation?
Well the Drake equation, which was invented by Frank Drake in 1952 in fact, is meant to be a way of trying to estimate how many intelligent civilisations are out there now as we speak, and so it has a number of factors, some of which are astronomical, some of which biological, which you multiply together to get the number of civilisations. So the kind of factors are first of all you need a star like the Sun and can’t be too different from the Sun otherwise it wouldn’t be suitable for us. Second factor is it’s got to be a single star, it must have a planetary system and probably it needs a planet like Jupiter to deflect asteroids, or most asteroids, away from the region of the Earth. Then the next factor is you have to have a planet like the Earth, more or less the same, could be a bit bigger, a bit smaller, bit nearer in so it would be a bit hotter, it could be a bit further away, so it would be slightly cooler, but not very much. And so those are the astronomical factors, you put them together and you find that the number of planets like the Earth that are formed per year is about one thousandth of a terrestrial planet is formed in our galaxy per year.
Now there are the other factors, the biological factors and so on. So the first one is the probability that life will evolve, life will form on a planet like Earth. So, given that bacteria emerge very quickly in history of the Earth, that might be 1, the probability might be 1. The next factor is the probability that life will evolve to an intelligent, technologically civilised creature like ourselves: now, the optimists, those that believe that they are everywhere believe that factor is also 1, but I think that a lot of the biologists are very sceptical of that, there seem to be so many lucky chances that seem to have let to our evolution that that factor could be a lot less than 1. But let’s assume it’s 1 for the moment. And then the final factor is how long a technological civilisation lasts. Now, if it lasts 1000 years, say, put down 1000th per year, multiply by 1000 , you end up with one civilisation like us in our galaxy, and we’re it.
What's the Fermi paradox? How does that support your argument?
The Fermi paradox was put forward by Enrico Fermi, a famous physicist around 1950, and basically it’s in the form of a question – Where are they? Basically he was arguing that if there are technological civilisations pervading the galaxy then they would be here by now. And there is an additional part of that argument, which is that our Sun is going to die in a few billion years, and if we’re still around, and we’ve had a few billion years of technology, we’re bound to start thinking about moving to another planet, we’ll know where the other planets are and we’ll send out expeditions, it seems to me inevitable. And it only takes about a million years for a civilisation to spread through the whole galaxy in this way, just using technology not that different from what we have today. So I personally think that the Fermi paradox is a rather strong argument for saying that we are actually alone.
Tell us about SETI (Search for Extraterrestrial Intelligence). Does the failure of SETI to give any results tell us that there's nothing out there? Now what do you have to assume to make it worthwhile to listen for a signal?
Well, you have to assume that intelligent life is pervasive in the galaxy, that it’s abundant, you have to assume that they’re pretty much like us, you know, that they’re not immensely more sophisticated than us, because you wouldn’t imagine that they would signal to us if they were. And you have to assume that they’re not interested in space travel, in travelling. So for some reason they are not trying to colonise the galaxy, they’re not trying to escape from their star, they’re just interested in chatting to us. And so the idea is they’re sending out signals. In fact, the idea that inspires the SETI enthusiasts is that there’s a kind of galactic club of civilisations who are talking to each other and if only we could get on the right frequency we could join in the chatline, that is the sort of concept.
Well, my own view is that it’s unlikely to be successful because as I said I think that probably we are alone and it’s interesting that although there’s been a lot of work on SETI over the last 20/30 years, with ever-increasing sophistication in searches, they obviously haven’t detected anything, otherwise we’d have heard about it.
I could’ve accepted that civilisations are pervasive, that for some reason the evolution to intelligent life is a simple matter, there are many civilisations, but if so I believe the SETI programme would have been successful by now. I think the fact that the galaxy is so silent in terms of intelligent signals is telling us something, and it fits in with the fact that they haven’t come here in spaceships either.
What about the idea that intelligent alien civilisations wouldn't want to communicate with us?
Some people like to suggest that they are there, but they stay hidden from us. And there could be 2 reasons why they would do that – one is they’ve already investigated us and decided that we’re so unpleasant that we’re in quarantine, they do not wish to allow us to join the galactic club so they make sure that we’re not aware of them. Another is that they regard us as we regard ants. I mean, we look down at an ant’s colony, it’s extremely clever and sophisticated, there they are waving their feelers at each other and we see communicating, so they have some kind of a society and so on.
Nevertheless, we don’t think ants represent somebody we could have a conversation with. And so maybe they are so advanced that we are not worth having a conversation with. That’s possible, but as I say, if there are civilisations that are so advanced, and they’re everywhere, I think that they would be interested in our real estate and they would just come and step on us, like we step on ants.
Dr Jack Cohen is an evolutionary biologist, whose interests include speculating on what alien life would look like. Dr Cohen thinks that SETI should be broadening its horizons and looking for more than just 'other astrophysicists' i.e. beings with intelligence similar to our own - intelligence can take on many different, often unexpected, forms.
What are the limits of the SETI approach?
SETI is a very interesting project. What it’s done which is very, very positive is created a community of people who are thinking of Earth as being just a tiny speck in space and the great galaxy around, and it’s wonderful. But what it has not done is to imagine a larger technology than we have. Essentially what it’s doing is using, well, radio waves are really like smoke signals, they’re such an ancient technology even for us – we’ve only been technological for, what a hundred years? And as far as we’re concerned radio waves are the great thing. But even radio waves are very difficult to pick up if you don’t know what you’re looking for.
One of the problems about thinking about life on other planets is that by and large it’s physicists or astrophysicists who’ve done it, and what they look for is a way of producing astrophysicists, human astrophysicists – they’re very small-minded about the whole thing, I think. Now, when they look, therefore, at other solar systems – or this solar system – they do silly things like talking about a ‘sphere of possibility’ for life, which ranges from about Venus to about Mars. They say, you know, where water is liquid that’s where you’ll find it. But actually it’s not like that at all, it’s very very disjunct: Venus is no good because it’s gone over the top in heat, Mars is no good because it’s too small, but Europa, which is well outside the so-called ‘habitable’ zone is fine. So they’re just completely wrong in doing the ‘let us have a neat sphere of habitable zone and see if it will work’.
Can you explain the difference between intelligence and what you call 'extelligence'?
It seems to me that there are 2 ways of arguing about what alien life, life on another planet – or on this planet run again – would be like. And the first argument I have is this, that if something has happened many times on this planet, like photosynthesis, like flight, like fur – some plants have got fur, bumblebees have got fur, mammals have got fur, it’s a good trick for temp regulation – if you have several occasions when it’s happened, in several different evolutionary lines, then if we ran the Earth again, or if we found another aqueous planet, the default is that we would find those things. And I call them ‘universals’.
The alternative is the little contingent things we have - like airway crossing foodway and all the other bad bits of design mixing up our sexual system with our excretory system, so that we talk about dirty books – that is just a contingent thing, and we won’t find that elsewhere. So parochials and universals, and the interesting thing about intelligence is that the evolutionary story on Earth tells us that intelligence is a universal. We have squids and cuttlefish, octopuses, they’re a little group of intelligent creatures, they’re relatives of the clams and the snails, who are not intelligent at all. And then of course we have the mammals, a lot of mammals are intelligent, and birds are intelligent.
Now, none of those is going to be doing radio waves from SETI. What’s happened is that one mammal has picked up in addition to intelligence, extelligence. What we do is to build culture around ourselves, we have libraries, that know much more than any individual person; we have a ‘make a human being kit’, that makes each of us a very knowledgeable fraction of our culture. And that is what leads to technology, and possibly – or at least it does in human beings, and we mustn’t argue from the prejudices of astrophysicists out into the universe as a whole – but in us it leads to a wish to communicate with other creatures.
But perhaps the other creatures we’re talking about, the aliens, may have grown up as cave dwellers or altogether shyer creatures than us, maybe they’re much more herbivorous than we were, maybe there was a really nasty carnivore, or a nasty parasite that got you if you stuck your head up out of the burrow. And they have a mindset which is different from our, and it says find a hole and pull it in after you.
They will have many have stealth techniques, and we just simply wouldn’t know they were here if they didn’t want us to know. I have a very nice cartoon which I show on this occasion to my school lectures, which has a rather silly looking woman standing on a weighing machine and she’s got a card out of the weighing machine, and the caption is ‘I am not a weighing machine, I am a Martian, you are standing on my testicles’. And that always causes a laugh, it’s a nice joke. We wouldn’t know they were here if they didn’t want us to know. On the other hand, we ought to be able to see them, we ought to see the evidence of energy waves as spaceships go all over the galaxy, what the hell’s going on?
Well, for a start the galaxy is a lot emptier. But, I like to think that we’re looking in the wrong places and we don’t know how to look. I met actually an astrophysicist, friend of mine in England, in the Everglades. And he was sitting there in little glade, in the Everglades, and he was saying ‘where are all the animals?’. And there was a big alligator not 20 feet from him, there was a snake not 3ft from his foot, there were little lizards all over the trees and he was just blind to all of them, he couldn’t see them, it took a biologist’s eye. And I think that it might be that we’re not looking in the right places or in the right way – you need a search image, we don’t have a search image of what these aliens are like.
What do you think it'd be like if we came face to face with aliens? A few people will care ever such a lot, and most people won’t care at all because they think it’s already happened. It is said one survey showed that one third of middle American people had had some alien experience, and it dropped as low as one in ten in San Francisco and New York. But those aliens have been ever so busy if you really think that one in ten people has had an experience which they interpret as being something to do with aliens. Now, many of these experiences have certainly happened, I just doubt they’ve been anything to do with aliens. But because we are so ready, because we’ve been softened up – who knows, this may be a trick by aliens, to soften us up so when they really appear we won’t be surprised at all.
Dr Monica Grady is a mineralogist at the Natural History Museum. Dr Grady is an expert on meteorites and what makes the Earth special as a planet that supports life.
What are the special properties of the Earth that make life possible? How likely is it that other planets have these properties?
The Earth is special in all of its properties – plate tectonics, the atmosphere, magnetic fields and so on. There are other possibilities in our own solar system – Venus just a bit closer to the Sun than the Earth, and Mars just that little bit further out. But both those planets don’t seem to have any intelligent life on, or at least none that’s been in touch with us. Part of the reason is that these planets have taken different evolutionary pathways.
Mars is half the size of the Earth, it has cooled more quickly than the Earth, it presumably has a solid core, it doesn’t have this activity called plate tectonics, it’s lost its atmosphere, it has a sterile surface, it’s cold, it’s barren, it’s dry. Venus on the other hand is much hotter than the Earth, it’s been very active in terms of volcanic activity, in terms of molten rocks on the surface. So huge amounts of CO2 have been put out on this planet, which is the same size as the Earth, but it has a much, much thicker atmosphere because the CO2 couldn’t be taken away again, because it doesn’t have plate tectonics. I think it is unlikely that we’re going to find just the right sort of planet orbiting just the right sort of star beyond our own solar system, perhaps even beyond our own galaxy.
What are the conditions required for intelligent life to evolve?
We could perhaps regard the emergence of life as an inevitable consequence of physics and chemistry - you get the right ingredients, you get the right conditions, you get life. Whether that life is intelligent is a completely different matter. We’ve got billions of years of evolution, going from single cells on the Earth to intelligent life, but that hasn’t been a progressive evolution, there have been fits and starts, there have been great periods of evolution and then a break.
One of the biggest breaks happened 65 million years ago when a meteorite impacted the Earth and wiped out most species. At that particular time the dominant species, the dinosaurs, were wiped out and a very unimportant species, little furry mammals then were able to come to prominence. Without that impact perhaps intelligent life might not have emerged on the Earth, or it might be completely different. So we can’t just regard evolution, we need to think of these other things that have happened, these chance events as well as the general evolutionary sequence.
Why are we so obsessed about the idea of the existence of other intelligent life? What do you think we would learn about ourselves if we were to make contact?
Ever since the dawn of time people have looked up at the sky and seen the stars and wondered what’s out there – is there anything, is there anybody else out there? I think it’s a primitive, a primeval urge, perhaps ‘homo sapiens the conqueror’ - we like to think that we’re in charge. Perhaps we are worried that there’s something more intelligent than us out there, perhaps our instincts are more territorial and defensive. I hope not, I hope that if we do find intelligent life out there, life which is more intelligent than we are, I hope we’re open enough to be able to accept that and to be able to learn from them. I think that will be terrifically humbling though and I think it would destroy humanity’s ego to find that we’re not the top of the tree, that we are much more a lowly species than we like to think. But I hope that if that is the case then we have the humility to accept that and to learn.
What kind of ‘intelligence’ do you think we are likely to encounter if we do make contact with an extra-terrestrial being?
One of the problems with trying to define and understand ‘intelligence’ is that we only look at our own patterns of behaviour. It’s possible that there are different types of intelligences that we don’t understand, that we don’t appreciate, something which is so completely beyond our ken that that we wouldn’t even recognise it as intelligence when we see it. Ant colonies, bee colonies have a certain amount of intelligence, we perhaps say, ok, they’re intelligent in one way but not in another. I think this is where research on computers and computer networks and neural networks is going to help to try to understand actually what makes us tick and what makes us intelligent, then to help us carry that forward to looking for intelligence elsewhere.
Dr Chris French is a psychologist at Goldsmith's College, London. Dr French's specialisms include the psychology of the paranormal and he is interested in why we are so obsessed with the idea of alien civilisation.
What do you think the appeal of SETI is? The main appeal of programmes like SETI is simply to our innate curiosity. I mean, the reason we’re so successful as a species is because we are so curious. We want to know about our place in the universe, we want to know how special we are. At one extreme it may be that we’re very special, we may be the only advanced technological civilisation in the cosmos, on the other hand the cosmos may be teeming with life, and we just want to know what’s the answer. I think the idea that we’re not alone, that there are other exciting interesting places, possibly even one day to actually physically make contact with is something that has very deep appeal at a very deep emotional level, it is very reassuring to people. In addition to that it may well be that we could learn a lot from advanced alien civilisations.
Do you believe we’ve already had visits from aliens?
According to public opinion surveys a sizeable minority, and sometimes even a majority of the population believe that we’ve already had contacts with alien civilisations. Now, up until fairly recently this was based upon UFOs, things seen in the sky. The short answer is virtually all of those sightings can be explained in more mundane terms, those that can’t are probably the ones that we just don’t have enough information to explain them. More recently there’s been a spate of alien abduction claims. From a psychological point of view these are absolutely fascinating, but again there is no convincing evidence that there’s any reality to the experiences that are being reported.
Why would another civilisation bother contacting us?
There is the possibility that the Universe might actually be teeming with life and we might still never actually make contact. Basically, all these kinds of estimates of whether or not there is intelligent, advanced civilisations in the Universe depend upon Drake’s famous equation, which is basically guesswork. But even if we accept some of the more optimistic estimates and say that there might be up to one million advanced civilisations in our galaxy, that would still mean that only one star in 200 000 actually has such civilisation, and the average separation between them is about 300 light years. Now, the idea that these advanced civilisations might find us so fascinating that they’d come all that distance to make contact with us – it’s possible, but then again it’s possible that they’d see us as being about as interesting as ants on some beach on the other side of the world, and not make the effort.
So, is there intelligent life out there?
There’s always the possibility that there might be life elsewhere in the cosmos on lots of different planets, but that intelligent life hasn’t evolved. This raises the whole issue of what do we mean by intelligence anyway. I think according to most people who would adopt a Darwinian approach to this, the notion that an intelligent organism is going to survive better than the one that lacks intelligence would tend to put the pressure on intelligence developing. Another interesting question is whether or not the form of consciousness that may be manifest in that particular organism would be something that we would recognise as consciousness.
The problem is of course is that we just don’t understand even now what consciousness actually is, but one could envisage an advanced technological civilisation of automata, where there’s no kind of self-awareness in the sense that we’d have it, something we feel is very special and makes us human. That may be something in the realms of science fiction, maybe that kind of advanced intelligence always involves self-awareness and consciousness as we understand it, but the simple answer is we just don’t know.