Why life begins and ends on Earth - Advanced life is unique to our planet - despite Stephen Hawking and SETI’s best hopes, argues Steve Jones.
Stephen Hawking’s 70th birthday reminds us of his celebrated claim that, given the thousands of Earth-like planets outside the solar system, on purely statistical grounds life almost certainly exists somewhere else. The celebrated SETI (Search for Extra-Terrestrial Intelligence) programme assumes that living things will inevitably evolve to get smarter and smarter and may be sending out signals to be picked up by their distant fellows. So far, alas, it has heard nothing but noise.
Dead and alive: Schrödinger’s cat enraged Stephen Hawking
At 1.15 today in a public lecture at University College London, the biochemist Nick Lane will pour a dash of metaphorical cold water on that notion. He argues that advanced life (and that stretches from amoeba to us) is unique: that the chance of its origin is so remote that it happened only once, and almost certainly has no equivalent anywhere else.
Stephen Hawking once said: “When I hear of Schrödinger’s cat, I reach for my gun.” Whatever the reality of that simultaneously dead and alive feline, in 1943 the German scientist gave a series of talks in Dublin entitled What is Life?, which set out to define just what that state means to a physicist. He saw that what unites all living things is that they have an inside and an outside. They need energy to keep the two apart; without it, they die. Within their walls they make their own environment, safe from the random chemical noise all around. Life is no more than a local patch of order.
To keep the cruel and chaotic world at bay needs a rampart. Simple membranes can be made in the laboratory in conditions like those of four billion years ago, and will form globules that can trap other chemicals within. Other experiments hint that small molecules able to copy themselves, albeit inefficiently, can also be made – and many of their raw materials are floating around in the universe, occasionally falling to Earth in objects like the Murchison Meteorite. Such steps to the earliest life must have been slow indeed as natural selection, that series of successful mistakes, fashioned the first simple cells.
However, that earliest existence stagnated for a billion years – and their descendants, today’s bacteria, are still pretty torpid. They went nowhere because they could not generate enough energy to impose a decent dose of order on their internal being. Evolution proper did not really get going until the appearance of proper cells, with nuclei. These “eukaryotes” at once set off down a variety of paths, culminating in ourselves. Even the least elaborate versions are far more sophisticated than what had gone before.
The Entry of the Eukaryotes seems to have been a one-off, an overture to the opera of advanced existence. It depended not on the gradual trudge of natural selection (which does no more than tinker with the imperfect to make it slightly less so) but on one spectacular, unique and unexpected event. It involved a coalition: an agreement between early cells and bacteria, which were welcomed as collaborators. That, as in many coalitions, ended with one party in charge and the other a reluctant servant. The bacterial labourers now act only as power stations for their hosts. Their efforts led to a massive leap in cell size and in productivity, with many more genes at work than before, a hundred thousandfold increase in efficiency, and an explosion of innovation.
Without those cellular generators – mitochondria, as they are called – life would still be in the slow lane. All non-bacterial creatures share mitochondria, sex and the cell nucleus, each of which seems to have evolved only once (unlike, for example, eyes, which have appeared dozens of times) as a further hint that a single moment sparked off an evolutionary race which in the end led to Stephen Hawking’s talents.
Natural selection may well be grinding away on all those Earth-like satellites out there, and might even have generated some primitive forms of living creature. But the call for a single unique shift to a high-powered economy able to impose order upon itself happened just once in four billion years on our own planet, and is unlikely to have been answered anywhere else. That much reduces Hawking’s estimate of the chances of a brain like his being at work in a distant galaxy.
He, like many of his colleagues, has been critical of governmental attempts to foster junk science by insisting that physics researchers predict what the impact of their discoveries will be before they have made them. Nobody who believes that could occupy the same planet as any scientist – so perhaps it is not intelligence that we should be looking for in the void. ( telegraph.co.uk )
Stephen Hawking’s 70th birthday reminds us of his celebrated claim that, given the thousands of Earth-like planets outside the solar system, on purely statistical grounds life almost certainly exists somewhere else. The celebrated SETI (Search for Extra-Terrestrial Intelligence) programme assumes that living things will inevitably evolve to get smarter and smarter and may be sending out signals to be picked up by their distant fellows. So far, alas, it has heard nothing but noise.
Dead and alive: Schrödinger’s cat enraged Stephen Hawking
At 1.15 today in a public lecture at University College London, the biochemist Nick Lane will pour a dash of metaphorical cold water on that notion. He argues that advanced life (and that stretches from amoeba to us) is unique: that the chance of its origin is so remote that it happened only once, and almost certainly has no equivalent anywhere else.
Stephen Hawking once said: “When I hear of Schrödinger’s cat, I reach for my gun.” Whatever the reality of that simultaneously dead and alive feline, in 1943 the German scientist gave a series of talks in Dublin entitled What is Life?, which set out to define just what that state means to a physicist. He saw that what unites all living things is that they have an inside and an outside. They need energy to keep the two apart; without it, they die. Within their walls they make their own environment, safe from the random chemical noise all around. Life is no more than a local patch of order.
To keep the cruel and chaotic world at bay needs a rampart. Simple membranes can be made in the laboratory in conditions like those of four billion years ago, and will form globules that can trap other chemicals within. Other experiments hint that small molecules able to copy themselves, albeit inefficiently, can also be made – and many of their raw materials are floating around in the universe, occasionally falling to Earth in objects like the Murchison Meteorite. Such steps to the earliest life must have been slow indeed as natural selection, that series of successful mistakes, fashioned the first simple cells.
However, that earliest existence stagnated for a billion years – and their descendants, today’s bacteria, are still pretty torpid. They went nowhere because they could not generate enough energy to impose a decent dose of order on their internal being. Evolution proper did not really get going until the appearance of proper cells, with nuclei. These “eukaryotes” at once set off down a variety of paths, culminating in ourselves. Even the least elaborate versions are far more sophisticated than what had gone before.
The Entry of the Eukaryotes seems to have been a one-off, an overture to the opera of advanced existence. It depended not on the gradual trudge of natural selection (which does no more than tinker with the imperfect to make it slightly less so) but on one spectacular, unique and unexpected event. It involved a coalition: an agreement between early cells and bacteria, which were welcomed as collaborators. That, as in many coalitions, ended with one party in charge and the other a reluctant servant. The bacterial labourers now act only as power stations for their hosts. Their efforts led to a massive leap in cell size and in productivity, with many more genes at work than before, a hundred thousandfold increase in efficiency, and an explosion of innovation.
Without those cellular generators – mitochondria, as they are called – life would still be in the slow lane. All non-bacterial creatures share mitochondria, sex and the cell nucleus, each of which seems to have evolved only once (unlike, for example, eyes, which have appeared dozens of times) as a further hint that a single moment sparked off an evolutionary race which in the end led to Stephen Hawking’s talents.
Natural selection may well be grinding away on all those Earth-like satellites out there, and might even have generated some primitive forms of living creature. But the call for a single unique shift to a high-powered economy able to impose order upon itself happened just once in four billion years on our own planet, and is unlikely to have been answered anywhere else. That much reduces Hawking’s estimate of the chances of a brain like his being at work in a distant galaxy.
He, like many of his colleagues, has been critical of governmental attempts to foster junk science by insisting that physics researchers predict what the impact of their discoveries will be before they have made them. Nobody who believes that could occupy the same planet as any scientist – so perhaps it is not intelligence that we should be looking for in the void. ( telegraph.co.uk )
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