DNA strands

‘The discovery of primitive life on another planet wouldn’t change the world’: Andrew May, Astrobiology

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The question of there being other life forms elsewhere in the universe is one of the greatest mysteries of all. What do we mean by extraterrestrial ‘life’ in any case? Author and scientist Andrew May has the answers.

The first problem facing anyone seriously considering the question of whether there is life elsewhere in the universe is to reach an understanding of what the concept of ‘life’ might mean. Without that we can’t prepare ourselves for the implications of whatever answers our scientific investigations may return. It’s an issue Andrew May is happy to address in his new book ‘Astrobiology: The Search for Life Elsewhere in the Universe’, but it’s one that, even when expressed as a pair of simple alternatives, immediately seems to take us away from what we’re all secretly hoping for: the universe of ‘Star Wars’ and ‘Star Trek’.

“It’s worth making the distinction,” says May, “between the search for advanced aliens – SETI, or in more modern parlance ‘technosignatures’ – and the search for ‘biosignatures’ indicating the presence of non-technological life: anything from primitive bacteria to an intelligent pre-industrial society.” Perhaps counterintuitively, we’ve been searching for technosignatures for about six decades (“without success”, May reminds me) despite the fact that the technology deployed in that search is continuously improving, while we continually come up with new ideas of what to look for. “On the other hand, the search for biosignatures has barely begun.” May assures me that this aspect of the search for life out there, “should really get going in the next couple of decades, and I’d expect the first positive results in that sort of timeframe too”.

Before we get too excited about “positive results”, what May is talking about is traces of microscopic life – not technologically advanced civilisations – leading him to suspect that “non-experts [including journalists] are going to be thoroughly underwhelmed”. But the good news is that we know carbon to be one of the most common elements in the universe. We also know that it has a propensity for forming molecules, “as complex as DNA, with billions of atoms in it”, making the carbon-abundance a good place to start our search. We also “know what sort of biosignatures to look for with carbon-based life”. But what if there are life-forms out there not built on carbon? May admits that, “we could fail to spot alien life if it was chemically different from life on Earth”.

As we are culturally predisposed to think of alien life as being big-brained green humanoids, and because we are also ‘Earth-centric’, refusing to believe that there is nothing particularly special about our geographical location in the universe, it’s sometimes difficult to take seriously the idea that there are other living organisms in the cosmos. But, as May says in ‘Astrobiology’, what we have here is a strong case for managing our expectations. “If you mean ‘life’ in the literal scientific sense of microscopic single-celled organisms, seaweed, earthworms or whatever, then it’s not an outrageous or shocking idea that such things might exist on dozens of other planets within a few light-years of Earth.” More cautiously, “if you’re thinking about a technologically savvy civilisation at a comparable or higher level than ourselves, you’re going to have to look much further afield. But the chances are pretty good that they – or the machines they built – are still around somewhere in the galaxy.”

We read it for you


Extra-terrestrial life is a common theme in science fiction. But is it a serious prospect in the real world? Astrobiology is the emerging field of science that seeks to answer this question, and ‘Astrobiology’ is the title of Andrew May’s latest book addressing just such a question, giving his expert overview of our current state of knowledge, looking at how life started on Earth, the tell-tale ‘signatures’ it produces, and how such signatures might be detected elsewhere in the Solar System or on the many ‘exoplanets’ now being discovered by the Kepler and TESS missions. Then there’s the really big question: when we eventually find extra-terrestrials, will they be friendly or hostile? Part of Icon Books’ ‘Hot Science’ series, ‘Astrobiology’ is a concise and balanced examination of a subject where the questions challenge our assumptions as much as the answers.  

Astrobiology is a serious subject and May is perfectly qualified to discuss it. With an academic background in astrophysics from Manchester University to go with his degree in natural sciences from the University of Cambridge, post-doctoral research at both Groningen and Oxford and an industry career in operational analysis relating to novel aerospace and underwater systems, it would seem that he’s not the sort of writer to allow popular culture to pull the wool over his eyes for so much as a second. But he is also “perennially interested in ideas, especially way out ones”, so while on the one hand he is the author of several books of popular science, he is also a contributor to the Fortean Times, a magazine with the tagline: ‘The world of strange phenomena.’

Critically, when it comes to astrobiology, one of the main reasons to trust him as an authority is that while he is “fascinated by anything to do with the search for extraterrestrial intelligence” he initially couldn’t even pretend to be excited by micro-organisms, wherever they may live. “That’s an important admission to make – and one not many writers on the subject will admit to. But I’m sure it’s a common view among the public at large.” What this means is that when he took on the task of writing ‘Astrobiology’, May was intending to focus mainly on the more interesting subject of intelligent aliens while, “glossing over the lower life forms as quickly as possible. In spite of myself, as I was writing it, I got really quite excited about the latter aspect and it ended up filling half of the book.”

The position is simple. In a nutshell, we’ve been looking for ‘little green men’ – the ‘technosignature’ side of the equation – for more than half a century and we can’t find any. We’ve barely started looking for evidence of biology on a microscopic level – ‘biosignatures’ – and there is a strong case for being optimistic about making discoveries in our lifetimes. It follows then that the next big question is what impact all of this will have on us Earthbound humans. “Call me cynical,” says May, “but I don’t think that the discovery of primitive life on another planet would change the world very much.” This is because scientists will say that this is exactly what they expected to find, while tabloid journalists will raise the objection that this simply wasn’t what they meant by alien life.

“At the other extreme,” May continues, “receiving a SETI-style message from an alien civilisation – if it was an unambiguously artificial signal – would be earth-shattering. That’s true even if the message were undecipherable, or just a beacon containing no real information, because it would almost certainly originate from a civilisation a lot more advanced than our own. And if that could be decoded... just imagine what we’d learn from it.” What gets far fetched to the point of impossibility is the idea that we will soon discover humanoid aliens that look and behave like ourselves. “Science fiction has a lot to answer for here, together with the closely related folklore of flying saucers and alien abductions.”

‘Astrobiology: The Search for Life Elsewhere in the Universe’ by Andrew May is published by Icon Books, £8.99


Interstellar engineering

Even if there are thousands of intelligent civilisations in the galaxy, only a small minority of them – if any – are likely to be blasting out radio messages we could detect. If the messages are aimed at us, or other civilisations like us, the senders would have to share our interest in interstellar communication – which may not be the case. On the other hand, if we’re just talking about accidental leakage from domestic communications, it implies that the aliens are going about it in an energy-inefficient way – which seems unlikely for an advanced civilisation. It’s far more likely that any aliens that might exist are simply minding their own business. Without knowing the exact nature of that business, there’s still a chance that it would produce ‘technosignatures’ – tell-tale signs that aliens are there – that we could detect.

If they are on the same technological level as us, for example, we can start by imagining what unusual features about our own planet might reveal our presence to a distant observer. One possibility is nightglow. Seen from space, the side of the Earth that should be pitch black – the side facing away from the Sun – is artificially illuminated by millions of tiny pinpoints of light, coming from cities and other products of human civilisation. The situation on any other planet with a similar civilisation will be the same, resulting in a characteristic signature in terms of light emitted. By astronomical standards the light will be very faint, and our current telescopes aren’t powerful enough to spot it at a distance measured in light years – but the next generation of instruments might be.

Another tell-tale sign of our presence is something we can be less proud of, and that’s industrial pollution in the atmosphere.

Edited extract from ‘Astrobiology’ by Andrew May, reproduced with permission.

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