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| Let's listen out for alien life – and remember we might not understand it | Let's listen out for alien life – and remember we might not understand it |
| (34 minutes later) | |
| Space probes have explored the main bodies of our solar system, revealing varied and distinctive worlds – but worlds unpropitious for life. There may once have been living organisms on Mars (and there may be life on the moons of Jupiter and Saturn) but there are no “Martians” of the kind familiar from science fiction. | Space probes have explored the main bodies of our solar system, revealing varied and distinctive worlds – but worlds unpropitious for life. There may once have been living organisms on Mars (and there may be life on the moons of Jupiter and Saturn) but there are no “Martians” of the kind familiar from science fiction. |
| Within our solar system, Earth is the only Goldilocks planet – not too hot and not too cold for water to exist. But the propects of finding advanced life brighten a billion-fold when we extend our horizons to the other stars – far beyond the range of any probe we can construct today. The most exciting recent breakthrough in astronomy has been the realisation that most stars are orbited by retinues of planets, just like our sun is. And that there are literally billions of Earth-like planets in our Milky Way galaxy. | Within our solar system, Earth is the only Goldilocks planet – not too hot and not too cold for water to exist. But the propects of finding advanced life brighten a billion-fold when we extend our horizons to the other stars – far beyond the range of any probe we can construct today. The most exciting recent breakthrough in astronomy has been the realisation that most stars are orbited by retinues of planets, just like our sun is. And that there are literally billions of Earth-like planets in our Milky Way galaxy. |
| Would these other planets have lush biospheres? Or is our Earth unique, all others being sterile and lifeless? We know too little about how life began, and what evolutionary paths it might take, to answer this basic question. | Would these other planets have lush biospheres? Or is our Earth unique, all others being sterile and lifeless? We know too little about how life began, and what evolutionary paths it might take, to answer this basic question. |
| Understanding the transition from complex molecules to the first replicating and metabolising systems — from the non-living to the living — is fundamental unfinished business for biochemists. We still don’t know whether the emergence of the first life was a so-called fluke, or whether it is near-inevitable in the kind of “chemical soup” expected on any planet resembling the young Earth. | Understanding the transition from complex molecules to the first replicating and metabolising systems — from the non-living to the living — is fundamental unfinished business for biochemists. We still don’t know whether the emergence of the first life was a so-called fluke, or whether it is near-inevitable in the kind of “chemical soup” expected on any planet resembling the young Earth. |
| But there is a second question: Even if simple life exists, what are the odds that it evolves into something that we would recognise as intelligent? Here on Earth, it took 3bn years before the so-called Cambrian explosion led to the emergence of the immense variety of lifeforms on the land that in turn led to humans – evolving by Darwinian selection, punctuated by major extinctions, such as the event 65m years ago that wiped out the dinosaurs. Even if primitive life were common, the emergence of what we imagine to be advanced life may not be – it may depend on many contingencies. | But there is a second question: Even if simple life exists, what are the odds that it evolves into something that we would recognise as intelligent? Here on Earth, it took 3bn years before the so-called Cambrian explosion led to the emergence of the immense variety of lifeforms on the land that in turn led to humans – evolving by Darwinian selection, punctuated by major extinctions, such as the event 65m years ago that wiped out the dinosaurs. Even if primitive life were common, the emergence of what we imagine to be advanced life may not be – it may depend on many contingencies. |
| Related: Anybody out there? Massive radio wave project to scan far regions for alien life | |
| So we can’t lay odds on how many exo-planets harbour advanced life. Searches for extraterrestrial intelligence (Seti) are a gamble. But they are surely a worthwhile one, even if there are heavy odds against success, because of the huge philosophical import of any detection. A manifestly artificial signal – even a message as boring as a set of prime numbers or the digits of pi – would convey the momentous message that intelligence wasn’t unique to the Earth and had evolved elsewhere. And it could take for a very different form from us. Seemingly artificial signals could come from super-intelligent (though not necessarily conscious) computers, created by a race of alien beings that had already died. | So we can’t lay odds on how many exo-planets harbour advanced life. Searches for extraterrestrial intelligence (Seti) are a gamble. But they are surely a worthwhile one, even if there are heavy odds against success, because of the huge philosophical import of any detection. A manifestly artificial signal – even a message as boring as a set of prime numbers or the digits of pi – would convey the momentous message that intelligence wasn’t unique to the Earth and had evolved elsewhere. And it could take for a very different form from us. Seemingly artificial signals could come from super-intelligent (though not necessarily conscious) computers, created by a race of alien beings that had already died. |
| Even if intelligence were widespread in the cosms, we may only ever recognise a small and atypical fraction of it. Some “brains” may package reality in a fashion that we can’t conceive. Others could be living contemplative lives, perhaps deep under some planetary ocean, doing nothing to reveal their presence. The only type of intelligence we could detect would be the (perhaps small) subset that used a technology attuned to our own parochial concepts. It makes sense to focus searches first on Earth-like planets orbiting long-lived stars. But science fiction authors remind us that there are more exotic alternatives. | Even if intelligence were widespread in the cosms, we may only ever recognise a small and atypical fraction of it. Some “brains” may package reality in a fashion that we can’t conceive. Others could be living contemplative lives, perhaps deep under some planetary ocean, doing nothing to reveal their presence. The only type of intelligence we could detect would be the (perhaps small) subset that used a technology attuned to our own parochial concepts. It makes sense to focus searches first on Earth-like planets orbiting long-lived stars. But science fiction authors remind us that there are more exotic alternatives. |
| The great philosopher Ludwig Wittgenstein famously said: “If a lion could speak, we couldn’t understand him.” Even if signals were being transmitted, we may not know how to decode them – just as an old-fashioned radio engineer familiar only with amplitude-modulation might have a hard time decoding modern digical communications. | The great philosopher Ludwig Wittgenstein famously said: “If a lion could speak, we couldn’t understand him.” Even if signals were being transmitted, we may not know how to decode them – just as an old-fashioned radio engineer familiar only with amplitude-modulation might have a hard time decoding modern digical communications. |
| But the culture gap with aliens need not be unbridgeable. After all, if the aliens had the technology to generate signals that we could detect, they would share with us an understanding of physics, maths and astronomy. They may come from planet Zog and have seven tentacles, but they would be made of similar atoms to us. They would, like us, trace their origins back to the big bang 13.7bn years ago. So we could develop a language that describes the things we have in common, and then move on to other subjects. | But the culture gap with aliens need not be unbridgeable. After all, if the aliens had the technology to generate signals that we could detect, they would share with us an understanding of physics, maths and astronomy. They may come from planet Zog and have seven tentacles, but they would be made of similar atoms to us. They would, like us, trace their origins back to the big bang 13.7bn years ago. So we could develop a language that describes the things we have in common, and then move on to other subjects. |
| It makes sense to listen, rather than transmit. (Any two-way exchange would take decades, so there would be time to plan a measured response – and no scope for snappy repartee). | It makes sense to listen, rather than transmit. (Any two-way exchange would take decades, so there would be time to plan a measured response – and no scope for snappy repartee). |
| There are three reasons why an expanded search is timely. First, technical advances in electronics and signal processing allow much more sensitive searches. Second, we’ve now discovered some Earth-like planets that are obvious targets. And a third reason is that the advent of social media and citizen science would enable a global community ofyoung and old to participate in this cosmic quest. | There are three reasons why an expanded search is timely. First, technical advances in electronics and signal processing allow much more sensitive searches. Second, we’ve now discovered some Earth-like planets that are obvious targets. And a third reason is that the advent of social media and citizen science would enable a global community ofyoung and old to participate in this cosmic quest. |
| That’s why we should surely accaim the Breakthrough Initiative’s major investment. This will secure time on the world’s best radio telescopes and develop instruments to scan the sky in a far more comprehensive and sustained fashion than ever before. It’s a gamble – the chances may be small but the stakes are so high that we’d surely all like to see searches begun in our lifetime. | That’s why we should surely accaim the Breakthrough Initiative’s major investment. This will secure time on the world’s best radio telescopes and develop instruments to scan the sky in a far more comprehensive and sustained fashion than ever before. It’s a gamble – the chances may be small but the stakes are so high that we’d surely all like to see searches begun in our lifetime. |
| Perhaps the galaxy already teems with advanced life, and our descendents will “plug in” to a galactic community – as rather junior members. | Perhaps the galaxy already teems with advanced life, and our descendents will “plug in” to a galactic community – as rather junior members. |
| On the other hand, Earth’s intricate biosphere may be unique and the searches may fail. This would disappoint the searchers. But it would have an upside – and would not render life a cosmic sideshow. | On the other hand, Earth’s intricate biosphere may be unique and the searches may fail. This would disappoint the searchers. But it would have an upside – and would not render life a cosmic sideshow. |
| Evolution is just beginning. Our solar system is barely middle aged and if humans avoid self-destruction, the post-human era beckons. | Evolution is just beginning. Our solar system is barely middle aged and if humans avoid self-destruction, the post-human era beckons. |
| Far-future life and intelligence could be as different from us as we are from a bacterium. Life from Earth could spread through the entiregalaxy, evolving into a teeming complexity far beyond what we can even conceive. If so, our tiny planet — this pale blue dot floating in space — could be the most important place in the entire cosmos. | Far-future life and intelligence could be as different from us as we are from a bacterium. Life from Earth could spread through the entiregalaxy, evolving into a teeming complexity far beyond what we can even conceive. If so, our tiny planet — this pale blue dot floating in space — could be the most important place in the entire cosmos. |
| Humans could then be less cosmically modest — our actions would resonate far beyond the Earth. Either way, our cosmic habitat — this immense firmament of stars and galaxies — seems tuned to be an abode for life. From a simple big bang, amazing complexity has unfolded, leading to our emergence. | Humans could then be less cosmically modest — our actions would resonate far beyond the Earth. Either way, our cosmic habitat — this immense firmament of stars and galaxies — seems tuned to be an abode for life. From a simple big bang, amazing complexity has unfolded, leading to our emergence. |
| Even if we are now alone in the universe, we may not be the culmination of this drive towards complexity and consciousness. But thanks to the Breakthrough Initiative, there will be a serious scientific effort to probe these fundamental mysteries which all can follow with fascination. | Even if we are now alone in the universe, we may not be the culmination of this drive towards complexity and consciousness. But thanks to the Breakthrough Initiative, there will be a serious scientific effort to probe these fundamental mysteries which all can follow with fascination. |