Wednesday, 3 July 2013

Extraterrestrial life: Where is everybody?

A recent article by Amy Shira Teitel published by Al-Jazeera (here) has me on my high horse again about the myth of extraterrestrial life. The article caught my eye because the author attributes the first search for extraterrestrial life to the ancient Greek philosopher, Epicurus, and in the same breath portrays both Plato and Aristotle as the enemies of science. This is a grotesque misreading of Greek philosophy in itself, but it is a standard furphy in the standard histories of science. The author casually rehearses some standard scientific myths, the main one being that the Epicurean doctrine of infinite worlds is the same thing as modern science's extended cosmogeography of the observable universe. This is not true, anymore than the similar doctrine found in Buddhism (well before Epicurus) is a precursor to the modern scientific cosmology, regardless of what Buddhist modernists will tell you. 

But it is not the distortions of Greek philosophy that have me going, it is the pervasive and entrenched idea that the search for extraterrestrial life is advancing in leaps and bounds, underpinned by the assumption that the universe is teeming with life that is just waiting to be discovered. This is the popular science-fiction inspired view of the universe. In the article in question, the author details the continuing discovery of so-called exo-planets, or earth-like planets circling distant suns in a familiar manner. The point of the article is that since we have discovered such distant worlds, the chances of finding life elsewhere in the universe are much enhanced. For the first time we have discovered places where terrestrial-style life might exist. 

This is all very well, but it does not change one iota one simple, overwhelming and exceedingly curious fact: namely that so far we have not discovered a single living thing - nothing - beyond the biosphere of the earth. The fact that we are discovering places where ET life is "likely" or at least "possible" only serves to underline this fact. We are finding places where life might be, but so far we have not the slightest indication that there is indeed life in any such places. Most people are unimpressed by this fact. They think it is just a matter of time. But there are others - like me - who are struck by the apparent lack of life in the universe as against the potential for it. 

On earth life absolutely irrepressible and ubiquitous. Life is everywhere. Life is found in every single nook and cranny of the earthly environment. We find microbial life that can survive in the most extraordinary places: the very deepest trenches of the ocean or even the insides of a volcano. There is virtually no place on earth where life has not adapted to the prevailing conditions. Some microbes can live on nothing but sulphur. Wherever we look, life. The evidence of the world around us is that life is amazingly adaptable; living organisms can survive in the most inhospitable conditions. 

This would lead us to the reasonable expectation that the rest of the universe would be the same, that life will have adapted to even the harshest environments. If microbes can live inside an active volcano, or at the bottom of the ocean where there has been no light or oxygen for thousands of years, then why not in the gaseous soups of the atmosphere of Venus, or the thin atmospheres of the Moon or Mars, or elsewhere? And yet, as soon as we step outside of the Earth's biosphere, what do we find? Nothing. Not a thing. Zip. 

The great Italian astro-phycists Firmi noted this. He asked, confronted with these facts, "Where is everybody?" For him, that is, the fact that we did not find any life - not so much as a single living cell - in space, on the moon or so far on Mars, is an extraordinary thing in itself. The contrast between the Earth and elsewhere could not be more stark. For Firmi, this requires an explanation. Why is life ubiquitous on Earth but totally absent outside of the biosphere? We know from terrestrial examples (such as microbes in volcanoes or in deep sea trenches) that life could conceivably adapt to conditions on the Moon or on Mars or on Venus or the moons of Saturn. In theory, it should be possible for forms of life to adapt to an environment as hostile as the surface of the Sun. We know that life *could* exist in such harsh environments. And yet, it doesn't. 

Even if, for example, we uncovered evidence that there had once been life on Mars (a fond hope among science types these days) it still begs the question: why, then, isn't life ubiquitous and profuse and irrepressible, as it is on Earth? That is the real mystery. But it is a mystery overlooked by science-fiction scientism. "Where is everybody?" It's a question no one asks. Articles like that of Ms Teitel only underline the problem. All the latest discoveries prove is that life *should* exist in abundance, but so far, as far as we know, it doesn't. These discoveries make it more probable, but as the probabilities go up the fact that we have failed to encounter any ET life so far becomes all the more remarkable. We may be left with the conclusion that, while the conditions for life are widespread, life itself is not. Why not? 

This situation is not likely to change any time soon. There is a very high chance that our best efforts to find life elsewhere in the solar system - even one single lousy bacteria would do - will come to nothing. On the other hand, there is a chance we might find evidence of life on Mars, or elsewhere, in the next few decades, but as I say, even if that is the case, it is likely to be an isolated instance that does not change the dramatic contrast between a living Earth and a dead solar system. We know already that the solar system is not teeming with life. Why not? That's the mystery. Why hasn't life adapted to other environments? We know that it can. Why hasn't it? If there is life beyond earth, why is it so thin on the ground? 

As Firmi noted, the evidence available to us on earth suggests that once life takes hold it can adapt to almost any circumstances. But that doesn't seem to have happened anywhere else in the solar system, and it is only surmise that it might have happened elsewhere. Outside of mathematical probabilities, and science fiction, we have no evidence of it at all. The facts are really quite different than what scientists feed to the popular imagination. The facts, rather, underline just how extraordinarily unique is life on earth. There may well be other life elsewhere - I don't deny it - but we already know that the universe - in contrast to the earthly environment - is not crawling with life. Life appears to be the exception. It certainly is in the solar system. Before space travel, people like Firmi had a reasonable expectation that life - in some form - would be the norm in outer space. We discovered that it isn't. 

Why is this important? My interest is to high-light the uniqueness - the miraculous extraordinariness of life on earth. The myth of ET life downplays this. It leads us to think that life is pedestrian, just as it encourages a mentality that thinks that if we mess up this planet we can all move to another one. There is no basis for that delusion at all. Indeed, all of our experience of space travel so far tells us that prolonged space travel is impossible for human beings. This is because human beings have a direct connection to the Earth. It is impossible for us to leave the Earth and remain human. Future space travel is likely to be done by robots and machines. Science mythology doesn't admit this fact, but it is true. The Earth is our unique home. That is never likely to change. On this, as on other things, science mythology is misleading. 

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