When I was a student, I took it for granted that the universe was teeming with life. It seemed obvious to me that there must be somebody or something out there somewhere and that our human destiny must surely lie among the stars.
Maybe I watched too many episodes of Star Trek and Dr. Who, because these sentiments were not shared by many of my scientific colleagues.
The prevailing view among scientists at that time was well captured by the words of the French Nobel Prize winning biologist, Jacques Monod, who in his book, Chance and Necessity, published in 1974 had the following to say:
"Man at last knows that he is alone in the unfeeling immensity of the universe out of which he emerged only by chance."
Thirty years on I think there has been something of a U-turn in the scientific community on the issue of the existence of extraterrestrial life.
The U.S. space agency, NASA, has recently launched its astrobiology program with the stated aims of seeking out life on other worlds.
The SETI community SETI stands for Search for Extraterrestrial Intelligence scan the skies with radio telescopes in the hope of picking up a message from some advanced alien civilization. They obviously believe that there is somebody out there. At least they hope there is, otherwise they are wasting their time.
Journalists and school children, when you take a straw poll, generally that assume that it is quite natural that there should be life throughout the universe.
Perhaps more importantly, Bill Gates recently in an interview with The New York Times, said he too thought that life is widespread in the universe. So you see there is quite a line up of opinion that we are, indeed, not alone.
I want to enumerate a few of the reasons, why I think the mood has changed.
But, first, [let me ask you], does it matter, whether or not we are alone?
Well, I think it does. A great deal hinges on the answer to that question. If it turns out that we are alone the our stewardship of planet Earth become even more important, because if it is the only place in the entire universe that anyone can call home, that gives us an awesome responsibility.
If we screw up and eliminate ourselves, I dont suppose we would kill off all life, but its not clear to me that sentient life, at least life capable of reflecting on the meaning of existence, would ever arise again anywhere on the universe. So we may be the only chance the universe has got for beings who can significantly understand their surroundings and think about what it all means.
Now, if we take a more optimistic approach that we wont screw up [and] that humanity will endure for the indefinite future, we could imagine a grandiose scenario in which we would spread beyond the Earth and go to inhabit other planets in the solar system and beyond that maybe spread across the galaxy to the entire universe.
That is a rather romantic view; perhaps its a rather extreme view, but its one possible scenario, if we are alone.
But suppose, we are not [alone].
Suppose that we share this wonderful cosmos with a myriad other sentient life forms; a myriad of other civilizations. Then it may be our human destiny to one day spread a little bit beyond the Earth and take our rightful place among the galactic community.
Having said that, I think there is a deeper reason why the question, are we really alone? matters.
It is no coincidence that Monod equated the non-existence of extraterrestrial life with atheism and nihilism. Blind chance or contingency, as philosophers call it, is the opposite of purpose. By attributing the emergence of life to chance alone, Monod could affirm the ultimate pointlessness and meaninglessness of existence.
But, by contrast, if the universe possessed ingeniously bio-friendly laws; laws able to coax life into existence, wherever the conditions are suitable if life were inevitable under Earth-like conditions then our own existence as part of this grand cosmic scheme would take on an altogether deeper significance, enough to make a nihilist squirm.
Let me now turn to what brought about this U-turn in sentiment. Why have scientists as a whole abandoned Monod and his bleak vision of life as a stupendous and probable accident emerging against all the odds, a chemical fluke?
Why have they abandoned that and embraced Star Trek instead?
Well Ive said that I have come up with a few reasons and I would like to take you through these one by one, before I draw my conclusions.
The first thing that has changed in the last 30 years, is a subject that John Percy dealt with admirably last night and that is the recent discovery of extra-solar planets. These are planets around other stars in our galaxy.
Until about five or six years ago, most astronomers assumed that other stars had planets but they had no direct evidence for that. But, now they do. To date about 20 stars have been identified as having planets around them, undoubtable most stars do and in the coming years, there will be many more discoveries of that sort.
I think there is now generally a view that planets are fairly common in the universe and, presumably, Earth-like planets are common, too. The technology doesnt yet exist to detect Earth-like planets in other star systems. But surely they are there. So they are plenty of potential abodes for extraterrestrial life.
The second factor, I think, that has changed in the last 30 years is the recognition that the building blocks of life; the so-called organic molecules, are actually fairly common throughout the universe.
Now, of course you find organic molecules here on the Earth in the biosphere, but again as John Percy mentioned briefly last night, some meteorites and, most notably the Murchison Meteorite that fell in Australia, are chock full or organic molecules including amino acids. They are important because they are the building blocks of proteins. Proteins are essential to life as we know it.
But these building blocks are found not only in meteorites. They are also found in the tails of comets and in interstellar space, in the large gas clouds, the interstellar grains that exist in the gaps between the stars. These grains have a large number of organic molecules including alcohol.
So, the stuff of life, the life encouraging substances are very common throughout the universe; right throughout the galaxy, the Milky Way galaxy we can see these same materials. It is tempting to believe that if the building blocks of life are everywhere, then life is everywhere.
The third reason, concerns discoveries which have taken place in the last 30 years; not out there in space, but right here on Earth. In particular, the discovery that Earth organisms can live in what we would call in extreme environments, live in places where biologists never thought to look in the past.
Historically, scientists were very surprised to find, 25 to 30 years ago, the existence of micro-organisms living in the hot volcanic springs at Yellowstone National Park, where the water comes bubbling up at very close to boiling point. There are organisms that can not only survive, but thrive in temperatures of 80% C or more. This was a great surprise, because most biologists assumed that nothing could live at that sort of temperature.
This was the beginning of a long series of surprises.
The next came in the late 1970s, when a submarine from Woods Hole Oceanographic Institute was sent to the bottom of the Pacific Ocean, to a region called the Galapagos Reach.
You probably know that the Earth is restless. The continents dont just sit there; they drift around. They are continually moving about and crunching against one another and sometimes one plate goes down and another one rides up above. The plates will move apart and the Earths crust will tear and this will release molten larva to the surface. Often this takes place under the sea.
You have this scenario where youve got very hot stuff coming up from below mixing with the cold water above. This creates thermodynamic pandemonium and along some of these ridges what you find is chimney-like orifices, fissures in the sea bed where dusky fluid is emanating at up to 300% C.
These have been dubbed black smokers on account of this dusky fluid which is emanating from the vents.
It is not smoke, but super-heated water laced with all sorts of minerals and goodies coming up from deep inside the Earths crust.
What came as an astonishing surprise to the scientists involved was that the region around these black smokers is teaming with life, all sorts of life; long tube worms, crabs, not in the 300%C heat, but still in pretty torrid conditions.
Although they are the conspicuous things, the most remarkable of the organisms are those that stand at the base of the food chain; they are bacteria, or like bacteria. They are micro-organisms and they make a living directly from the chemicals and the heat coming out of the Earths crust.
The micro-organisms that live close to these vents can flourish at temperatures in excess of 100%C. Some of them are quite comfortable at 110%C and from time to time the record gets broken. I am reliably informed that 113%C is the temperature at which the hottest known micro-organism can comfortably make a living.
It turns out that there is another record which is, how long can you survive in an autoclave? The record was 121%C and they still come out smiling. So it is truly remarkable. There is an unofficial record of 169%C. I will come back to that a little later.
These black smokers are home to some remarkable organisms, but because it is pitch black, they dont depend upon sunlight for making a living. There is a subtlety here because many of the microorganisms indirectly depend on surface life through dissolved oxygen and other oxygenated substances that make their way down from above.
There are known to be true primary producers, microbes that can function in complete darkness and make biomass directly from hydrogen and carbon dioxide coming up out of the Earths crust.
So, we have a completely alternative life chain and food chain existing on and, indeed, beneath the Earths surface; deep down there under the sea in the dark.
This opens up the prospect of a type of life, indeed, an entire ecosystem that does not depend on sunlight ultimately for its survival. That was a great surprise. The surprises went on and on.
Theres an Australian ship thats part of the international ocean drilling program that goes out into the southern oceans and they drill down through the sea bed for all sorts of reasons. One of the reasons is to see if anything is living there.
Remarkably, these microbes I have been talking about not only inhabit the surface of the sea bed around these black smokers, they live deep down into the rock of the sea bed itself; down to about a kilometer and there is no end in sight. That is as deep as they have drilled. Some of these organisms have been removed and cultured in the laboratory and their genetic composition studied.
The surprises didnt stop here. It turns out that if you drill down on the land as well, it is seething with tiny microbes.
When I first learned about this, I thought, well, how can they live in solid rock, because there isnt any space. But, it turns out that even solid rock has plenty of little pores and these are tiny critters and they can squeeze into very small spaces. If you take a cubic centimeter of rock you might be talking millions or even billions of bacteria and other microbes.
Its beginning to seem that the Earths biosphere extends deep into the crust. It is not a case of what you see is what you get. There is a lot more that is hidden.
Some people have computed that there might be as much biomass out of sight under the ground as there is on the Earths surface. This has been a revelation, because if life can exist both within the Earth as well as on it then it clearly opens up the possibility of life existing beneath other planetary surfaces. So, maybe those planets we have taken as being sterile and barren are actually harbouring life after all, but out of sight deep under the ground.
When you sequence genes of these organisms, called hyperthermophiles, that like the heat, whether they live deep under the ground or deep beneath the sea bed or around these hot springs and things, you can relate them to each other.
I think you have all probably heard about the tree of life. This was Darwins idea. Life began in a simple form and branched and re-branched and re-branched to form something like a gigantic tree. We human are one little twig leaf on that tree of life, along with kangaroos, mushrooms, E. coli and anything else you would like to name.
But, we are all related. You can trace us all back to a common ancestor. Geneticists can measure the evolutionary distance between organisms in terms of the numbers of differences in their genetic structure. This is now fairly routine.
For example, we share I think it is 98.5 per cent of our DNA with chimpanzees. So we are very closely related. The closer you are the more DNA you share.
So, it is very interesting to look at these weird microbes that live in these extreme environments-- in my book I call them super bugs to see how they are positioned relative to all the other stuff.
When I was in school, we were always told that life consisted of two things, either plants or animals. A better classification came along, which was basically single-cell organisms, without nuclei and all the rest. So there were still two categories.
But these genetic studies have shown that there are, in fact, three great kingdoms of life.
And they are: bacteria, which I think you would recognize; eukarya, all the more complex cells, the cells with nuclei and all the multicellular organisms, like man and animals. Then, weve got this other kingdom which nobody knew existed before, called the archaea. The reason nobody knew they existed is cause they looked just like bacteria.
The point I want to make is that clearly all of the deepest and hence implied oldest branches of the tree of life are occupied by these hyperthermophiles. That suggests to me that life started out hot and deep and these are like living fossils.
They are still living the ancient life style three or four billion years on, whilst their more venturous cousins who have come to the surface of the Earth, with the cooler conditions, have gone forth and multiplied and inherited the surface of the Earth.
So that suggests a scenario in which life starts inside a planet and colonizes the surface, only at a later stage.
How does this square with what we know about the earliest life on Earth?
We can, of course, trace the fossil record backwards and there are fossil hunters who go out to look for dinosaurs, for example. The dinosaurs were wiped out 65 million years ago, probably by an asteroid impact. And 65 million years is very recent in geological terms. Remember, the Earth is four and a half billion years.
It turns out that the oldest known fossils come from Australia, from a place in Western Australia, which perversely is called North Pole.
There you will find these rather indistinct, but nevertheless, very significant fossil micro- organisms. They are photosynthesizing bacteria that form mats called stromatolites, with distinctive geological features. It seems quite likely that this was all happening three and a half billion years ago.
Photosynthesis is a rather sophisticated process and it must have taken a long time to develop. So, clearly this was not the first life. The problem about finding anything earlier than this is that it is extremely hard to find old rocks, because the Earth is restless and continually reprocessing the surface material. So,, it is tricky to spot rocks which are much older.
But there are some rocks in Greenland, 3.85 billion years old which dont have fossils in them. However, these rocks have been modified that suggests that photosynthetic life was at work even as early as 3.85 billion years.
Why is this significant?
You have may have seen the films Deep Impact and Armageddon.
Im sure you know after John Percys lecture last night that it is for real; asteroids really do hit the Earth from time to time.
The bombardment in the first 700 or 800 hundred million years of the solar systems history was very intense. It is called the heavy bombardment period. It tailed off about 3.8 billion years ago.
If it is true that life was already established on planet Earth 3.85 billion years ago, it seems to be something of a paradox. And the only way a paradox can be resolved, I think, is to suppose that life was not living on the surface until very late on in the piece. It was living deep under the ground, keeping its head down away from this bombardment.
I might tell you that if an asteroid of say two or three hundred kilometers across were to hit the Earth, the effects would be quite awesome. First of all it would make a crater, I should think about the size of Ontario and Quebec combined. A big hole.
The impactor itself would vaporize and the blast would be enough to strip away much of the atmosphere and replace it with incandescent rock vapor.
Can you imagine the entire planet swathed in glowing rock vapor at a temperature of about 300%C.
The effect of that would be to boil the oceans dry and create a blanket of super-heated steam and vaporized rock. This would last for some months, during which a heat pulse would travel right down deep into the Earths crust at least a kilometer killing everything in its path.
The only way you could survive is if you were really pretty deep under the ground. Because it is hot when you go down deep into the Earth even today, you have to be a hypothermophile to withstand these conditions. So it strongly suggests that life began, the first life on Earth, deep under the ground.
What, then, about other planets? Is it possible there is life beneath the surface of those as well?
When we look for life elsewhere in the solar system, the number one candidate is always the planet Mars. The point about Mars is that it contains two features which in light of what I have just been telling you, we can see a probable essential to the genesis of life. One is water and the other is volcanoes.
In 1977, NASA sent two spacecraft, called Viking, to the surface of Mars specifically to look for life. What they found was not very promising. Now Viking was equipped with a robot arm that could reach out and scoop up some dirt and stuff it into a little onboard laboratory and pour on some nice nutrient broth and see if anything happened.
Something did happen. It was all very complicated, but the consensus among the scientists was that it was exotic soil chemistry at work and not living organisms.
After that, most space scientists thought that Mars was not only red, but dead; not really worth further study.
That was back in the late 1970's, before many of the discoveries I have just told you about were made. More recently, NASA sent another spacecraft, called Pathfinder, to Mars.
The reason that people have now got excited about Mars as a prospect for life is an early picture from one of the Mars fly by missions. It shows signs of a river valley; in fact, a river delta. Now it is dried up today, but it is quite clear that in the past, water flowed freely on Mars.
Mars Global Surveyor, which is in orbit around Mars now, has returned pictures showing a river valley that resembles very much the Grand Canyon. You see the river that once flowed along the base of the canyon. It looks as if there were really two types of hydrological activity on the surface of Mars: one was meandering rivers in the conventional sense and the other were gigantic floods.
You see huge flood plains, sometimes hundreds of kilometers across, where clearly water erupted or burst through some sort of dam, perhaps an ice dam or something, and spewed right across the Martian surface.
All of this was in the past. Today Mars is effectively a freeze-dried desert. The surface temperature rarely gets above normal melting point of water, the atmosphere is pitifully thin, there is no ozone layer, so the surface is drenched in deadly ultraviolet radiation.
But, it is clear that it was not always thus. From the erosion and the impact craters, it can be deduced that probably Mars went off the ball about 3.5 billion years ago. Just about the time that we know that life was getting established on Earth.
Mars does have one other crucial feature, volcanoes. In fact, it has the largest volcano in this solar system. The combination of water and volcanoes can create these black smoker like conditions, which because of that gene sequencing data, is very suggestive of being the primeval environment in which life could be incubated.
So, is it possible that on Mars we have an example of a second genesis; of life originating independently from Earth and evolving in its own way? Is it possible that there is still life on Mars today?
I think the answers to the latter question is yes, but deep down.
All of the water on Mars today is either in the polar caps or locked in the permafrost, the rubble that is left lying around from the ancient impacts. It is locked up in that, but deep underground where the planets heat has melted some of the water, there could be liquid reservoirs rather similar to conditions deep beneath the Earths surface.
If there is life there, its going to be expensive to get at because you have not have to go to Mars, you have to drill deep down into the surface to find it. There are plans afoot for these sorts of things.
While I have been talking about the hazards to early life from these large impacts, clearly some of the big impacts have enough punch to knock rocks directly into space.
In other words, a comet or an asteroid hitting Mars could eject an enormous amount of material into the solar system. Some of this material could come to Earth .
[In fact, a piece of rock] found in Antarctica in 1984, called Alan Hills 84001, excited NASA scientists when the found inside little features which, at least for a while, they claimed were like fossilized bacteria.
The very fact that there exists Mars rocks on Earth there are 14 that have been identified shows that rocks can come from Mars to Earth and its clearly possible that Martian microbes could hitch a ride on those rocks and make the journey themselves.
So is it possible, that life on Earth began on Mars? Are we in fact, all Martians?
Well not only is it possible, I think there is quite a good case that we are. It is not an overwhelming case because, of course, material can go the other way too. The Earth will be hit from time to time with a rock big enough to knock Earth rocks off into space and some of those would go to Mars.
We know that Mars was warm and wet and just like the Earth at a time when we know that there was life on Earth. So it must have happened. It must have been the case, say 3.6 billion years ago that a large impactor would have hit the Earth and sent Earth rocks to Mars, carrying Earth microbes and they would have arrived on Mars and it would have seemed very much like home.
I think there was life on Mars if for no other reason than it would have got there from Earth. But, did that Earth life itself originally come Mars?
Earth and Mars can cross contaminate each other, but where did it start? Did it start on Mars and come to Earth, or did it start on Earth and go to Mars? Did it start on both independently?
Why do I think Mars is more favorable than Earth as the true Garden of Eden?
The reason is that Mars is a smaller planet and, therefore, cooled quicker. So, the comfort zone for these heat-loving microbes was deeper sooner.
In other words, if the place you want to be is deep down in the ground, then you want to be as deep as you can get, then the cooler it is down there the better. It would have been cooler on Mars. In fact I think 4.2 even 4.3 billion years ago Mars might have been a suitable place for subterranean life.
Mars also had the advantage, because it lacked a global ocean. It may have had a small ocean, but nothing like our oceans on Earth.
Therefore, this nightmare scenario of the incandescent rock vapor, super-heated steam blanket wouldnt have happened on Mars. In fact, on statistical grounds, because it was a smaller target, it may well have missed some of these really large impacts that the Earth undoubtedly suffered.
So it looks like Mars was a more favorable environment in the early stages; not now, but then.
But, of course to go from Mars to Earth inside a meteorite is not a very comfortable thing to do.
There are two hazards that suggest themselves. One is the shot of ejection. You wouldnt think that an explosion that has the power to excavate a crater maybe many kilometers across would leave much alive in its vicinity. You would expect the shock of being kicked into space with accelerations of about 20,000 Gs would be enough to destroy even tiny microbes.
It turns out that is not the case. In fact, recent experiments with artillery shells in Sweden showed that there are microbes here on Earth that can survive 30,000 Gs with no trouble. So the acceleration doesnt kill them. Nor do the rocks all get compressed and themselves heat shocked.
What happens is that the surface layer of rocks that get ejected just fly straight off into space. The craters which are made by these impacts are excavated. They are not pounded down by the blow from above. The impactor itself explodes, vaporizes sends out a shock wave and lifts out a huge volume of material.
It turns out that a 20 kilometer impactor hitting Mars would propel about a billion tons of rock into space which would not have been heated above 100% C. So it would not have killed at least by heat any Martian inhabitants.
Once in outer space, of course, its problems are not over. The hazards of traveling through space are the cold and the deadly radiation. Cold it turns out, is not a problem for bacteria. They love it. In fact, the best way of preserving them is to put them into cold storage. It helps with vacuum conditions because they lose the water, so desiccated freeze-dried bacteria do live on.
Radiation, however, is another matter. Cocooned inside a rock, microbes would be well shielded against radiation and the worst hazard turns out to be the residual radiation of the rock itself.
Computations at the University of Arizona suggest that inside a rock of with a radius of about 200 centimeters, pretty well all of the cosmic rays, ultraviolet and other sources of radiation like solar flares, would be screened out and the radioactivity of the rock itself would become life threatening for any bacterial inhabitant after about 32 million years. That is quite a long time. If you can just hang on for 30 million years or so, then everything should be all right, so long as you hit the Earth.
You can compute how much of this Martian detritus gets to Earth and it turns out to be about 7.5 per cent. So. if we are talking about these billions and billions of tons, that is still a lot of material. About a third of that arrives within about 10 million years. So you see it is actually not so bad. A certain amount of material, I think would get here with viable microbes in it.
That raises the whole scenario of a killer plague from the red planet.
Could it be that the next Martian meteorite to fall maybe in your backyard, carries virulent organisms, super bugs from the red planet that are going to sweep through population and wipe us all out?
One of the reasons, I think we dont need to worry about that is because these rocks have been arriving throughout Earth history. It has been computed that more than a trillion tons of Martian material which would not have killed its bacterial inhabitants would have arrived on Earth in the last four billion years. More of it would have come before that.
In other words, if there was any danger from Martian microbes it would have manifested itself by now. Thats important, because in 2005 NASA is going to launch its Mars sample return mission. It is going to send a spacecraft there to grab some rocks and bring them back to Earth for analysis in the laboratory.
There are a number of people who are scared by this and are threatening legal challenges and so on because they want the rocks to be properly quarantined and, indeed, they will be. But some people still worry.
My message is dont worry, because we would have been done in already by these Martian pathogens if they really were dangerous.
Of course there may be no life there at all. We just dont know.
What we have, then, are several different scenarios.
The possibility that life started on Mars and came to Earth, and took up residence as soon as it could deep in the Earths crust to avoid this impact problem. Or that it started on Earth and went to Mars. Maybe it flourished on Mars, maybe it didnt.
Or that it started independently on Earth and Mars. In other words that there was a second genesis on Mars.
There is another possibility which is that it started somewhere else entirely and came to both of them.
It does get complicated. But the point I want to make is this. From a philosophical significance, the distinction is crucial as to whether we are dealing with life happening once or twice in the solar system. It is possible to find life on Mars and yet for life still to be unique. In other words, it happened only once. Maybe it happened on Mars and came to Earth and thats it. There are just two planets in the universe that have life on them.
On the other hand, if it turns out, that life independently started on both Earth and Mars, then it is quite clear that the universe will indeed be teeming with it. It would be inconceivable that there are only two planets in the entire universe that have life on them and they are both right here in this solar system.
So, it has to show that there is life almost everywhere.
That brings me now, to the fifth reason why there has been a change of heart on the subject of life elsewhere in the universe.
The term might well be loosely called biological determinism. There is a feeling I think it is a romantic feeling, rather than a scientific valid one among researchers in this field that there is something like a life principle. It is what Christian De Duve, a Nobel prize winning biologist calls, a cosmic imperative.
De Duve writes:
"Life is almost bound to arise wherever physical conditions are similar to Earth." Some people express this by saying life is written into the laws of physics.
Now why should people believe that?
One reason is an experiment that was performed in Chicago by a student called Stanley Miller at the behest of his supervisor, Harold Urey.
This was attempt to recreate the primordial soup in the laboratory. What they did was to get methane, ammonia and hydrogen gases thought to have existed in the earths primaeval atmosphere and add some water and spark electricity through it for about week.
At the end of that time the flask was full of sludge, a reddish brown sludge found to contain these famous amino acids, the building blocks of proteins.
They were obviously very pleased with that result and for a while it looked like the Miller/ Urey experiment was the first step on the road to making life in a test tube.
Some people were upset by that; other people were inspired. It depends on your point of view.
Anyway there was a feeling, and still is in some quarters, that the Miller-Urey experiment was indeed a first step on a road with the destination life written on it; a road down which a chemical mixture would be inexorably conveyed by the passage of time. In other words, to make life to get life you just need to do more of the same.
Ive likened this a little bit to the chemical recipe theory of life. Making life is like baking a cake. You mix a little bit of this and a little bit that and you simmer for a million years and you add a bit more of something else and then a pinch of salt and then you stir it and, hey, presto it lives!
That really, for a hundred years at least, has been the prevailing view among scientists working on this subject of biogenesis. Life is all about getting the chemistry right; the right chemical proportions mixed in the right ways and you will make life.
I think that way of thinking is a hangover from the 19th century; the notion that living material was some sort of magic matter.
I think we now understand life somewhat differently. Life isnt really magic matter. The best way I can describe life is the living cell is a little bit like super computer. The thing that makes life remarkable is not what it is made of not he stuff of life [but] its remarkable information processing and storing facility. DNA the famous life giving molecule is like a genetic data bank, contains the data, this data is actually in code; a mathematical code based on the number three.
It is a very clever idea. These days we are sold on the virtues of going digital. We have got digital radios, digital television, digital computation. We all know that going digital is a remarkably good way of manipulating matter or manipulating anything in the world.
Nature went digital four billion years ago, because life as the sort we know of on Earth is based on this digitization principle.
We think that we invented cyberspace. We didnt. The bacteria invented cyberspace four billion years ago. Because that is really what life is all about. It is the manipulation and organization of information in cyberspace. That is what it is doing. It is not really about chemistry.
Of course, there must be a chemical pathway that leads from a mixture of lifeless substances to the first living thing; life is based on chemistry. Life harnesses chemistry, but the thing that makes life remarkable is not that it is doing some very special sort of chemistry, br cause most of the chemistry its doing is actually rather mundane.
It is just sort of a complicated highly organized chain of chemical processes and it is this digitization of information based aspect to it that is the remarkable thing.
It seems to me that to try to understand how life originated it is not really a problem of chemistry at all; its a problem of information theory and complexity theory. We dont really want to know how actual molecules did it in real space. We would like to know how the information was organization in this way in cyberspace.
The problem is that we dont yet understand the principles that govern information and complexity well enough to know how this could have come about. But the naive view, that just because you find the building blocks of life all around the universe means you must find life around the universe, I think is as silly as saying, just cause you see a pile of bricks, you are going to see a house.
A house is made of bricks, but it is much more than a pile of bricks. The bricks have to be arranged and organized in a particular specific elaborate specified pattern. That is true of life. You cant just have any old amino acids hooked up to any others. Everything has got to be in exactly the right arrangement and the right sequence, otherwise it is biologically non-functional.
The problem is, just like houses are not written into the laws of physics, I dont think life is written into the laws of physics. I dont see how it could be, because the laws of physics are very general. If life is about information, all of the laws of physics can do is move information around. They can shift it from place A to place B. They cant create information. They cant inject it.
So, I dont think we are going to find the answer to life among the laws of physics and chemistry. I think we have got to search for some other principles.
I am not saying that biological determinism is false. What I am saying is that on the basis of known physics and chemistry, we have no reason to believe it. There is no known scientific principle that compels matter to organize itself into life. There is no known organizing principle of that nature.
That doesnt mean there isnt such a principle. But, we havent discovered it yet, so we have no right to say it just on the basis that the building blocks of life are scattered around the universe, that life is scattered around the universe; no right to say that whatever.
The conclusion that I am coming to is that if, indeed, we are not alone in the universe; if it is teeming with life and its formed independently, [and] it hasnt got splashed there in the manner I have described, then there must be deep principles of organization at work that supplement the known laws of physics and chemistry.
Otherwise, I dont think you have any right to claim that there is life elsewhere. Im not sure many scientists would let you want to go as far as that.
I think a lot of them have been rather glib, and they are saying, sure, there is life everywhere, without realizing the very profound assumptions that go into that.
Ive been talking about finding microbes on Mars; very exciting that would be.
But some people think what is much more exciting is finding intelligent life and maybe even technological civilizations way out there in the galaxy.
This is the subject of SETI, The Search for Extraterrestrial Intelligence. [The project employs radio telescopes around the world to eavesdrop on thousands of target stars in the hope of detecting radio signals of artificial origin].
I think there is a widespread misconception that there is some sort of conspiracy, that the scientists really know that we are being watched by aliens and that there are messages that have been received and its all been suppressed and the CIA is in on this and all the rest of it.
Well, if so, they should be coming in now and hauling me away because I am pretty sure there is no conspiracy.
This is all open scientific research done by qualified astronomers, often in their spare time, when they are taking time out from what some people might call more serious astronomy. I have to say that this is a needle in a haystack search with a vengeance, because we dont know that there is anybody out there.
Even if there is we have no idea whether they would spend time and money signaling us and even if they did we might be pointing the telescoping in the right direction and just tuned in to the wrong wave length, or they may have just gone to bed and we missed the message. There are all sorts of things that could have gone wrong.
The way I describe this whole project it is a glorious, but almost certainly futile quest. I think it is great to do it, because it is very cheap.
I think it is a wonderful thing to do. I think it is wonderful, even if after 100 years, there is zilch.
The reason is that it provides an opportunity for people like me to go to places like Hawaii and sit down and talk about the significance of it all.
It makes us think [about] who we are. What is our place in the universe? What is human destiny?
Envision our own situation in a 1,000 years or 10,000 years what will we be doing? What will we be thinking about? What will be our priorities? Will we be trying to signal them? Will we care?
Will we have all turned ourselves into some sort of computers? Will we have uploaded our consciousness into some global Internet and just go off into cyberspace and enjoy ourselves?
So, it really is a useful way of forcing us to think about our ultimate destiny. I think thats such a wonderful thing to do for such a modest budget, when were talking just a few million overall to keep SETI going. Its great stuff.
The biggest instrument theyve got is the Arecibo radio telescope in Puerto Rico and thats capable of communicating with a similar instrument anywhere in the galaxy.
So, if theres another Arecibo out there in another Puerto Rico 50,000 light years away then well get to know about that.