Life in a rut: if microbes are commonplace, where does that leave intelligent aliens?

A few years ago I wrote about how Mars' seasonal methane fluctuations suggested - although far from confirmed - that microbial life might be present just under the Martin surface. Now another world in our solar system, the Saturnian moon Enceladus, has ignited discussion along similar lines.

The Cassini probe conducted flybys of Enceladus over a decade, revealing that Saturn's sixth largest moon was venting geyser-like jets of material, including water vapour, from its southern polar region. The material being emitted from these vents also included organic compounds and methane, hinting that this distant moon's watery oceans may also contain alien methane-producing microbes. Whereas Titan and Europa were originally deemed the moons most suitable for life, Enceladus's status has now been boosted to second only to Mars, with conditions not dissimilar to those in the oceans of the early Earth.

Of course, unknown geochemical processes cannot be ruled out, but nonetheless the quality of the evidence is such as to invite further exploration of Enceladus. There have been at least seven potential mission designs proposed by various bodies, including NASA and ESA, to gain more information about the moon and its geysers. Several of these include landers, while others would fly through a plume in order to examine the vented material for biosignatures. However, to date none have received official funding confirmation. As it stands the first probe to arrive might be billionaire Yuri Milner's privately-funded Breakthrough Enceladus, rather than one from a major organisation. However, don't hold your breath: the earliest any of these missions is likely to reach Enceladus is at some point in the 2030s.

What happens if future probes find evidence of microbial life on both Mars and Enceladus? Or even, whenever a method is found to reach it, in the ice-covered oceans of Jupiter's moon Europa? The first key fact will be whether they are genetically independent of Earth biota or if the panspermia hypothesis - the delivery of microbes via cometary and meteorite impact - has been proven. If that turns out not to be the case and multiple instances of life arose separately within a single solar system, this has some profoundly mixed implications for the search for extraterrestrial intelligence (SETI). After all, if simple life can arise and be sustained on three or even four very different worlds - including bodies far outside their solar system's 'Goldilocks zone' - then shouldn't this also imply a much higher chance of complex alien life evolving on exoplanets? 

Yet despite various SETI programmes over the past few decades, we have failed to pick up any signs of extraterrestrial intelligence - or at least from other technological civilisations prepared to communicate with radio waves, either in our galactic neighbourhood or with super high-powered transmitters further away. This doesn't mean they don't exist: advanced civilisations might use laser pulses at frequencies our SETI projects currently don't have the ability to detect. But nonetheless, it is a little disheartening that we've so far drawn a blank. If there is microbial life on either Mars or Enceladus - or even more so, on both worlds, never mind Europa - then a continued lack of success for SETI suggests the chances of intelligent life evolving are far lower than the probability of life itself arising.

In effect, this means that life we can only view via a microscope - and therefore somewhat lacking in cognitive ability - may turn out to be common, but intelligence a much rarer commodity. While it might be easy to say that life on both Enceladus and Mars wouldn't stand much of a chance of gaining complexity thanks to the unpleasant environmental conditions that have no doubt existed for much of their history, it's clear that Earth's biota has evolved via a complex series of unique events. In other words, the tortuous pathways of history have influenced the evolution of life on Earth.

Whereas the discovery of so many exoplanets in the past decade might imply an optimistic result for the Drake equation, the following factors, being largely unpredictable, infrequent or unique occurrences, might suggest that the evolution of complex (and especially sapiens-level intelligent) life is highly improbable:

• The Earth orbits inside the solar system's Goldilocks zone (bear in mind that some of the planets have moved from the region of space they were created in) and so water was able to exist in liquid form after the atmospheric pressure became high enough.
• The size and composition of the planet is such that radioactivity keeps the core molten and so generates a magnetic field to block most solar and cosmic radiation.
• It is hypothesised that the Earth was hit by another body, nicknamed Theia, that both tilted the planet's axis and caused the formation of the Moon rather than having a catastrophic effect such as tearing our world apart, knocking it on its side (like Uranus) or removing its outer crust (like Mercury).
• The Moon is comparatively large and close to the Earth and as such their combined gravitational fields help to keep Earth in a very stable, only slightly eccentric orbit. This is turn has helped to maintain a relatively life-friendly environment over the aeons. 
• The Earth's axial tilt causes seasons and as such generates a simultaneous variety of climates at different latitudes, providing impetus for natural selection.
• The Great Unconformity and hypothesised near-global glaciation (AKA Snowball Earth) that might have caused it suggests this dramatic period of climate change led to the development of the earliest multi-cellular life around 580 million years ago.
• Mass extinctions caused rapid changes in global biota without destroying all life. Without the Chicxulub impactor for example, it is unlikely mammals would have radiated due to the dominance of reptiles on the land.
• Ice ages over the past few million years have caused rapid climate fluctuations that may have contributed to hominin evolution as East African forests gave way to grasslands.

The evolutionary biologist Stephen Jay Gould often discussed 'contingency', claiming that innumerable historical events had led to the evolution of Homo sapiens and therefore that if history could be re-run, most possible paths would not lead to a self-aware ape. Therefore, despite the 4,800 or so exoplanets discovered so far, some within their system's Goldilocks zone, what is the likelihood such a similar concatenation of improbable events would occur of any of them? 

Most people are understandably not interested in talking to microbes. For a start, they are unlikely to gain a meaningful reply. Yet paradoxically, the more worlds that microbial life is confirmed on, when combined with the distinct failure of our SETI research to date, the easier it is to be pessimistic; while life might be widespread in the universe, organisms large enough to view without a microscope, let alone communicate with across the vast reaches of interstellar space, may be exceedingly rare indeed. The origins of life might be a far easier occurrence than we used to think, but the evolution of technological species far less so. Having said that, we are lucky to live in this time: perhaps research projects in both fields will resolve this fundamental issue within the next half century. Now wouldn't that be amazing?

The Square Kilometre Array: is it the wrong big science for New Zealand?

I've previously written about the problems besetting some mega-budget science projects and the notion that perhaps they should lose precedence to smaller programmes with quicker returns to both science and society. Of course there are advantages to long-term international STEM collaboration, including social, economic and political benefits, but there is a good case for claiming that projects are sometimes initiated without a full appreciation of the details.

Take for example, the Square Kilometre Array or SKA, the largest science project New Zealand has ever been involved with. Headquartered at the UK's Jodrell Bank Observatory (incidentally, I've been there a few times and it's well worth a visit if you're in the vicinity), twelve key nations are collaborating to construct two main arrays, one in Australia and the other in South Africa and some of its neighbours. The combined arrays will have a sensitivity fifty times greater than previous radio telescopes, allowing them to survey the sky far faster than has been done before and look back in time much earlier than current instruments.

But such paradigm-shifting specifications come with a very high price tag – and the funding sources are yet to be finalised. The €1.8 billion project is scheduled to start Phase 1 construction in 2024 and aims to begin observations four years later. Research will include a wide range of fundamental astrophysical questions, from exploring the very early universe only 300,000 years after the Big Bang to testing general relativity, gaining information on dark energy and even some SETI research.

The New Zealand contribution is organised via the Australia-New Zealand SKA Coordination Committee (ANZSCC) and is geared towards data processing and storage. The Central Signal Processor and Science Data Processor are fundamental components of the project, since the radio telescopes are expected to generate more data than the world currently stores.  As well as closer collaboration between the scientists and engineers of various nations, one of the aims of SKA is to become a source of public science education, something I have repeatedly pointed out is in desperate need of improvement.

So if this all seems so promising, why has the New Zealand Government announced that it may pull back from committing the outstanding NZ$23 million (equal to less than 10% of Australia's funding)? To date, the country has paid less than NZ$3 million. In 2015 I discussed the danger of the country falling behind in cutting-edge STEM research and Rocket Lab aside (which is after all, an American-owned company despite its kiwi founder) the situation hasn't really changed. so why did Research, Science and Innovation Minister Megan Woods declare this potential about turn, which may well relegate New Zealand to associate membership status?

The initial answer appears to be one of pure economics. Although the project is generating development of world-class computer technology, a report has questioned the long-term benefits from investing such comparatively large sums of public money. India is already an associate member while Germany has been considering a similar downgrade for some years and Canada may follow suit. The project is already  a decade behind schedule and New Zealand had hoped to be an array-hosting nation but lost out due to a lower bid from South Africa. SKA is run by a same-name not-for-profit organisation and so presumably any financial rewards are of a secondary nature (perhaps along the lines of patents or new technologies that can be repurposed elsewhere).

Interestingly, New Zealand's science community has been divided on the issue. While Auckland University of Technology and Victoria University of Wellington have objected to the downgrade, the university of Auckland's head of physics Richard Easther has support the Ministry of Business, Innovation and Employment (MBIE) decision, saying that far from providing financial and long-term science benefits (in both applied computing and astrophysical data), SKA is a white elephant, hinting that it might well be obsolete by the time it starts gathering data.

Another University of Auckland astrophysicist, Dr Nick Rattenbury, argues that the nation's public funding infrastructure is currently too primitive for it to become involved in such international mega-budget STEM projects. I simply don't know enough detail to question whether such adages as you need to speculate in order to accumulate apply here; it's clearly a well-thought out programme, unlike say the politically-motivated yet vague and probably unworkable Predator Free 2050 scheme.

If SKA was committed to solving an immediate practical problem in the fields of say, environmental degradation, food and water production, or medicine, I would probably have no hesitation in supporting it whole-heartedly, regardless of the cost to the public purse. But the universe has been around almost fourteen billion years, so I for one don't mind if it holds onto a few of its fundamental secrets for a little while longer.

Space is the place: did life begin in the cosmic void?

A few weeks' ago I was watching a television documentary about the search for intelligence aliens and featuring the usual SETI experts Jill Tarter and Seth Shostak when I realised that we rarely see any crossover with research into non-intelligent extra-terrestrial life. Whereas the former is often seen by outsiders as pie-in-the-sky work by idealistic dreamers, the latter has more of a down-to-Earth feel about it, even though it has at times also suffered from a lack of credibility.

Based on current thinking, it seems far more probable that life in the universe will mostly be very small and entirely lacking consciousness, in other words, microbial. After all, life on Earth arose pretty much as soon as the environment was stable enough, around 3.7 billion years ago or even earlier. In contrast, lifeforms large enough to be visible without a microscope evolved around 1 billion or so years ago (for photosynthetic plants) and only about 580 million years ago for complex marine animals.

The recent publicity surrounding the seasonal variations in methane on Mars has provided ever more tantalising hints that microbial life may survive in ultraviolet-free shelters near the Martian surface, although it will be some years before a robot mission sophisticated enough to visit sink holes or canyon walls can investigate likely habitats. (As for the oft-talked about but yet to be planned crewed mission, see this post from 2015.)

Therefore it seems that it is worth concentrating on finding biological or pre-biological compounds in extra-terrestrial objects as much as listening for radio signals. The search can be via remote sensing (e.g. of molecular clouds, comets and asteroids) as well as investigating meteorites - bearing in mind that the Earth receives up to one million kilogrammes of material per day, although less than one percent is large enough to be identified as such.

The problem is that this area of research has at times had a fairly poor reputation due to the occasional premature claim of success. Stories then become widespread via non-specialist media in such a way that the resulting hype frequently bears little relation to the initial scientific report. In addition, if further evidence reverses that conclusion, the public's lack of understanding of the error-correcting methods of science leads to disillusion at best and apathy at worst.

One key hypothesis that has received more than its fair share of negative publicity has been that of panspermia, which suggests not just the chemicals of biology but life itself has been brought to Earth by cosmic impactors. The best known advocates are Fred Hoyle and Chandra Wickramasinghe, but their outspoken championing of an hypothesis severely lacking in evidence has done little to promote the idea. For while it is feasible - especially with the ongoing discovery of extremophiles everywhere from deep ocean vents to the coolant ponds of nuclear reactors - to envisage microbial life reaching Earth from cometary or asteroid material, the notion that these extra-terrestrials have been responsible for various epidemics seems to be a step too far.

It's long been known that comets contain vast amounts of water; indeed, simulations suggest that until the Late Heavy Bombardment around four billion years ago there may have been far less water on Earth than subsequently. Considering the volumes of water ice now being discovered on Mars and the Moon, the probability of life-sustaining environments off the Earth has gained a respectable boost.

It isn't just water, either: organic compounds that are precursors to biological material have been found in vast quantities in interstellar space; and now they are being found in the inner solar system too. That's not to say that this research has been without controversy as well. Since the early 1960s, Bartholomew Nagy has stirred debate by announcing the discovery of sophisticated pre-biological material in impactors such as the Orgueil meteorite. Examination by other teams has found that contamination has skewed the results, implying that Nagy's conclusions were based on inadequate research. Although more recent investigation of meteorites and spectrophotometry of carbonaceous chondrite asteroids have supplied genuine positives, the earlier mistakes have sullied the field.

Luckily, thorough examination of the Australian Murchison meteorite has promoted the discipline again, with numerous amino acids being confirmed as of non-terrestrial origin. The RNA nucleobase uracil has also been found in the Murchison meteorite, with ultraviolet radiation in the outer space vacuum being deemed responsible for the construction of these complex compounds.

Not that there haven't been other examples of premature results leading to unwarranted hype. Perhaps the best known example of this was the 1996 announcement of minute bacteria-like forms in the Martian ALH84001 meteorite. The international headlines soon waned when a potential non-biological origin was found.

In addition to examination of these objects, experiments are increasingly being performed to test the resilience of life forms in either vacuum chambers or real outer space, courtesy of the International Space Station. After all, if terrestrial life can survive in such a hostile environment, the higher the likelihood that alien microbiology could arrive on Earth via meteorite impact or cometary tail (and at least one amino acid, glycine, has been found on several comets).

Unmanned probes are now replicating these findings, with the European Space Agency's Rosetta spacecraft finding glycine in the dust cloud around Comet 67P/Churyumov-Gerasimenko in 2016. Although these extra-terrestrial objects may lack the energy source required to kick-start life itself, some are clearly harbouring many of the complex molecules used in life on Earth.

It has now been proven beyond any doubt that organic and pre-biological material is common in space. The much higher frequency of impacts in the early solar system suggests that key components of Earth's surface chemistry - and its water - were delivered via meteorites and comets. Unfortunately, the unwary publication of provisional results, when combined with the general public's feeble grasp of scientific methodology, has hindered support for what is surely one of the most exciting areas in contemporary science. A multi-faceted approach may in time supply the answers to the ultimate questions surrounding the origin of life and its precursor material. This really is a case of watch (this) space!

Presenting the universe: 3 landmark science documentary series

They say you carry tastes from your formative years with you for the rest of your life, so perhaps this explains why there are three science documentary television series that still have the power to enchant some decades after first viewing. Whilst there has been no shortage of good television science programming since - Planet Earth and the Walking with... series amongst them - there are three that remain the standard by which I judge all others:

1. The Ascent of Man (1972) - an account of how humanity has evolved culturally and technology via biological and man-made tools. Presented by mathematician and renaissance man Jacob Bronowski.
2. Cosmos (1980) - the history of astronomy and planetary exploration, interwoven with the origins of life. Presented by Carl Sagan (as if you didn't know).
3. The Day the Universe Changed (1985) - a study of how scientific and technological breakthroughs in Western society generate paradigm shifts. Presented by the historian of science James Burke.

All three series have been proclaimed 'landmark' shows so it is interesting to compare their themes, viewpoints and production techniques, discovering just how similar they are in many ways. For a start, their excellent production values allowed for a wide range of international locations and historical recreations. They each have a charismatic presenter who admits to espousing a personal viewpoint, although it's quite easy to note that they get progressively more casual: if Jacob Bronowski has the appearance of a warm elder statesman then Carl Sagan is the father figure for a subsequent generation of scientists; James Burke's on-screen persona is more akin to the cheeky uncle, with a regular supply of puns, some good, some less so.

To some extent it is easy to see that the earliest series begat the second that in turn influenced the third. In fact, there is a direct link in that Carl Sagan hired several of the producers from The Ascent of Man for his own series, clearly seeing the earlier show as a template for Cosmos. What all three have is something extremely rare in other science documentaries: a passion for the arts that promotes a holistic interpretation of humanity's development; science does not exist in isolation. As such, the programmes are supported by superbly-illustrated tie-in books that extend the broadcast material from the latter two series whilst Bronowski's book is primarily a transcript of his semi-improvised monologue.

In addition to considering some of the standard examples of key developments in Western civilisation such as Ancient Greece and Galileo, the series include the occasional examination of Eastern cultures. The programmes also contain discussions of religions, both West and East. In fact, between them the series cover a vast amount of what has made the world the way it is. So not small potatoes, then!

The series themselves:

The Ascent of Man

To some extent, Jacob Bronowski was inspired by the earlier series Civilisation, which examined the history of Western arts. Both series were commissioned by David Attenborough, himself a natural sciences graduate who went on to present ground-breaking series in his own discipline as well as commissioning these landmark programmes. (As an aside, if there are any presenters around today who appears to embody the antithesis of C.P. Snow's 'the two cultures' then Sir David is surely in the top ten).

Bronowski's presentation is an astonishingly erudite (for all its improvisation) analysis of the development of our species and its technological society. Although primarily focused on the West, there is some consideration of other regions, from the advanced steel-making technology of medieval Japan to Meso-American astronomy or the relatively static culture of Easter Island. Time and again, the narrative predates the encumbrance of political correctness: that it was the West that almost solely generated our modern technological society - the 'rage for knowledge' for once outshining dogma and inertia.

Of course, it would be interesting to see how Bronowski might have written it today, in light of Jared Diamond's ground-breaking (in my humble opinion) Guns, Germs and Steel. Although he works hard to present science, the plastic arts, literature and myth as emerging from the same basic elements of our nature, it is clear that Bronowski considers the former to be much rarer - and therefore the more precious - discipline. Having said that, Bronowski makes a large number of Biblical references, primarily from the Old Testament. In light of the current issues with fundamentalism in the USA and elsewhere, it is doubtful that any science documentary today would so easily incorporate the breadth of religious allusions.

If there is a thesis underlying the series it is that considering how natural selection has provided humanity with a unique combination of mental gifts, we should use them to exploit the opportunities thus presented. By having foresight and imagination, our species is the only one capable of great heights - and, as he makes no pretence of - terrible depths. As he considers the latter, Bronowski admits that we should remain humble as to the state of contemporary knowledge and technology, which five hundred years hence will no doubt appear childlike. In addition, he states that belief in absolute knowledge can lead to arrogance; if we aspire to be gods, it can only end in the likes of Auschwitz. But his final speeches contain the wonderful notion that the path to annihilation can be avoided if science is communicated to all of society with the same vigour and zest as given to the humanities.

Cosmos

I was already an astronomy and astronautics fan when I saw this series. Its first UK broadcast slot was somewhat later than my usual bedtime, so it seemed a treat to be allowed to stay up after the rest of the family had gone to bed. Like Star Wars a few years before, it appeared to me to be an audio-visual tour-de-force; not surprisingly, both the tie-in hardback and soundtrack album arrived on my birthday that year.

Nostalgia aside, another key reason for the series' success was the charisma of the presenter himself. Much has been written of Sagan's abilities as a self-publicist, and the programmes do suffer from rather too many staring-beatifically-into-the-distance shots (as to some extent replicated more recently by Brian Cox in his various Wonders Of... series). Of course, it must have taken considerable effort to get the series made in the first place, especially in gaining a budget of over $6 million. After all, another great science populariser, the evolutionary biologist Stephen Jay Gould, never managed to gain anything beyond the occasional one-off documentary.

What is most apparent is Sagan's deep commitment to presenting science to the widest possible audience without distorting the material through over-simplification. However, in retrospect it is also obvious that he was using ideas from several scientific disciplines, such as the Miller-Urey experiment, to bolster his opinions on the likelihood of extra-terrestrial life. To some extent his co-writers reined him in, the final episode given over not to SETI but to plea for environmental stewardship.

Whilst the series is primarily concerned with a global history of astronomy and astrophysics, supplemented with first-hand accounts of planetary exploration, Sagan like Bronowski is equally at home with other scientific disciplines. He discusses the evolution of intelligence and incorporates elements of the humanities with equal aplomb. Another key element is the discussion of the role superstition and dead ends have played in the hindrance or even advancement of scientific progress, from Pythagorean mysticism, via Kepler's conflation of planetary orbits with the five Platonic solids, to Percival Lowell's imaginary Martian canals. Although Sagan repeats his earlier debunking of astrology, UFO sightings and the like, he doesn't rule out the role of emotions in the advancement of science and technology, citing for example the rocket pioneer Robert Goddard's Mars-centred epiphany.

Perhaps the primary reason that the series - despite the obvious dating of some of the knowledge - is still so engaging and why Sagan's narration is so widely quoted, is that he was a prose poet par excellence. Even when discussing purely scientific issues, his tone was such that the information could be effortlessly absorbed whilst allowing the viewer to retain a sense of wonder. Of course, Sagan had ample assistance from his two co-writers Ann Druyan and Steven Soter, as clearly proven by their scripts for the Neil deGrasse Tyson-hosted remake Cosmos: A Spacetime Odyssey. Nonetheless, it is hard to think of another presenter who could have made the original series the success it was on so many levels.

The Day the Universe Changed

Although James Burke had already made a large-scale history of science and technology series called Connections in 1978, it contained a rather different take on some of the same material. By focussing on interactive webs, the earlier series was somewhat glib, in that some of the connections could probably be replaced by equally valid alternatives.

In contrast, The Day the Universe Changed uses a more conventional approach that clearly shares some of the same perspectives as the earlier programmes. Like The Ascent of Man and the Cosmos remake, mediaeval Islamic science is praised for its inquisitiveness as well as the preservation of Classical knowledge. Burke was clearly influenced by his predecessors, even subtitling the series 'A Personal View by James Burke'. Perhaps inevitably he covers some of the same material too, although it would be difficult to create a brief history without reference to Newton or Ancient Greece.

As with Bronowski, Burke integrates scientific advances within wider society, a notable example being the rediscovery of perspective and its profound effect on contemporary art. He also supports the notion that rather than a gradual series of changes, paradigm shifts are fundamental to major scientific breakthroughs. In effect, he claims that new versions of the truth - as understood by a scientific consensus - may rely on abandonment of previous theories due to their irreconcilable differences. Having recently read Rachel Carson's 1950 The Sea Around Us I can offer some agreement: although Carson's geophysical analysis quietly screams in favour of plate tectonics, the contemporary lack of evidence lead her to state the no doubt establishment mantra of the period concerning static land masses.

What Burke constantly emphasises even more than his predecessors is that time and place has a fundamental influence on the scientific enquiry of each period. Being immersed in the preconceived notions of their culture, scientists can find it as difficult as anyone else to gain an objective attitude. In actuality, it is all but impossible, leading to such farcical dead-ends as Piltdown Man, a hoax that lasted for decades because it fulfilled the jingoistic expectations of British scientists. Burke's definition of genius is someone who can escape the givens of their background and thus achieve mental insights that no amount of methodical plodding can equal. Well, perhaps, on occasion.

The series also goes further than its predecessors in defining religion as anti-scientific on two grounds: its demand for absolute obedience in the face of logic and evidence, with reference to Galileo; or the lack of interest in progress, as with the cyclical yet static Buddhist view, content for the universe to endlessly repeat itself. Burke also shows how scientific ideas can be perverted for political ends, as with social Darwinism. But then he goes on to note that as the world gets ever more complex, and changes at an ever faster rate, non-specialists are unable to test new theories in any degree and so are having to rely on authority just as much as before the Enlightenment. How ironic!

All in all, these common threads are to my mind among the most important elements of the three series:

1. Science and the humanities rely on the same basic processes of the human brain and so are not all that different;
2. Scientific thinking can be as creative an endeavour as the arts;
3. Scientists don't live in a cultural vacuum but are part and parcel of their world and time;
4. Religion is the most change-resistant of human activities and therefore rarely appears sympathetic to science's aims and goals.

As Carl Sagan put it, "we make our world significant by the courage of our questions and the depth of our answers." For me, these three series are significant for their appraisal of some of those courageous explorers who have given us the knowledge and tools we call science.

Are we alone? Wow, Little Green Men and the SETI faithful

According to the film version of Arthur C. Clarke's novel 2010: Odyssey Two, we now live in 'The Year We Make Contact'. Therefore it seems apt to take a quick look at the history of SETI, the Search for Extra-Terrestrial Intelligence, just in case fact should follow fiction. The recently-discovered antics of the Australian octopi that use coconut shells as mobile homes prove that it isn't just the music-loving, film-making and now liquid-quantifying chimpanzees who erode the boundaries between Homo sapiens and other animals. The Gallup mark mirror test has shown that apes, elephants, dolphins and even some birds have a degree of self-awareness exceeding that of human babies less than several months old. When combined with research into animal tool use and the archaeological evidence for rituals conducted by our extinct Neanderthal cousins, our species' mental abilities appear less and less distinctive. So if there are varying degrees of self-aware animals down here, what are the chances of intelligent life "up there"?

New analysis of the Murchison meteorite fragments which landed in Australia in 1969 has found 14,000 carbon-based compounds, including dozens of amino acids different from those known on Earth. If anything, this evidence is more intriguing than the now infamous Martian meteorite ALH 84001 which has so far failed to provide conclusive evidence of fossilised alien nanobacteria. But the idea of life being able to survive outside our comfortable biosphere has gained credence over the past few decades with the discovery of extremophiles, including the diverse organisms that live around submarine volcanic vents and the microbes that can survive gamma radiation several thousand times the dosage lethal to humans.

Whilst there has been a growth of interest in exobiology since the NASA experiments on Mars in the mid-1970s via the two Viking landers, a good deal of today's research investigates the notion of intelligent life elsewhere, largely via radio astronomy. Notable organisations include the Planetary Society, co-founded by the late Carl Sagan, and the Seti Institute, co-founded by Jill Tarter, the real-life model for Sagan's fictional Contact protagonist Eleanor Arroway. Yet despite the lack of positive data after half a century's effort, both the pro and con lobbies maintain passionate support for their ideas. One of the best-known SETI pioneers is American astronomer and astrophysicist Frank Drake, whose eponymous equation has been argued by both sides despite being deemed by some, including author Michael Crichton, as scientifically worthless. This stems from the fact that most of the values in the Drake equation, aiming to establish the potential number of civilisations in the galaxy capable of interstellar communication, are as unknown as when first written in 1960. Over the decades many researchers have had a go at 'filling in the blanks' and achieved results ranging from one (us) to over a million. Clearly, it is not an equation that can be resolved utilising our current knowledge of astrophysics, biology and almost everything in between.

As might be expected the UK's involvement in SETI has been somewhat minimal, although the 76-metre diameter Lovell Radio Telescope at Jodrell Bank has been used intermittently in this context since the late 1990s. Last month even saw the Royal Society host a SETI conference that included such astronomical luminaries as Martin Rees, Jocelyn Bell Burnell and Frank Drake. Unfortunately the traditional British no-nonsense approach lost Jodrell Bank in particular (and the country in general) its chance for pioneering SETI research when Bernard Lovell, in a decision he apparently later regretted, turned down a request to use the very same, then-named Mark 1, radio telescope in 1959.

Although over four hundred planets have been discovered (mostly indirectly) around other stars, none are obviously in the 'Goldilocks zone' where it is believed conditions are suitable for life. Having said that, the recent discoveries of water, mostly as ice, on the Moon, Mars, and two or three other satellites, are obviously positive signs. Then again, there is an enormous difference between those who support the notion of alien microbial life as opposed to intelligent organisms able to transmit signals between solar systems. As early as 1950 physicist Enrico Fermi developed his famous paradox which states that if there are any alien societies capable of interstellar travel, or just communications technology comparable to ours, then we should have found evidence by now. Despite several false alerts such as Jocelyn Bell Burnell's 1967 discovery of pulsars (which she initially labelled as LGM or 'Little Green Men') and the never-repeated 'Wow!' signal detected at Ohio State University in 1977, there has been no unequivocal evidence from the electromagnetic spectrum. In addition, and despite the plethora of orbiting telescopes from Hubble to WISE, there is no evidence for astro-engineering artefacts such as Dyson spheres that a more advanced civilisation might be able to construct.

One international project that has shown the immense level of international grass roots support for the hypothesis is SETI@home, which over the past decade has utilised five million home computers to process radio telescope signal data. Even though such current projects do not involve public money or remove time from research with seemingly more potential of success, there is still plenty of vociferous opposition, even from the scientific community. Arguments range from the practical, such as if we are already moving to fibre optics and digital signals perhaps radio broadcasts are too rare to be detected (some groups have now started laser-based research), to intense speculation on alien motives, which is clearly more in the realm of psychology than science. One of more interesting of the latter is the idea of deliberately non-communicative aliens: since like everyone else SETI researchers have the hard-wired human instinct for exploration, how can we have knowledge of an extraterrestrial psyche until we achieve contact? We surmise at our peril!

Of course another problem facing SETI is the manner in which it has been linked to the lunatic fringe. The unfortunate interest shown in the hypothesis by everyone from New Age mystics to conspiracy theorists taints the idea as verging on pseudoscience, regardless of how scientific the investigations themselves have been. In 1993 NASA's main SETI programme, at one point renamed the High Resolution Microwave Survey in an effort to remove the 'giggle factor', was cancelled after less than one year's operation. But then is it that surprising that US Government support has frequently been withdrawn, leaving only privately funded SETI projects as per today? High-profile supporters including Steven Spielberg and Microsoft co-founder Paul Allen may have boosted its status, but is SETI strictly scientific despite its methods and technology? After all, we could listen for thousands of years without receiving evidence, but as the old adage goes, absence of evidence is not necessarily evidence of absence.

Certainly the zeal with which Carl Sagan, probably the best known SETI advocate from the 1970s to 1990s, approached the enterprise had an almost religious air to it. His novel Contact develops this aspect by making the heroine rely solely on faith rather than physical evidence of her meeting with an extra-terrestrial. It could be argued that by presenting the alien in the guise of the protagonist's father, Sagan replaced conventional religiosity with a paternal God-like being with astounding powers. As Arthur C. Clarke's Third Law states (and as the Aztecs and many others found to their cost): 'Any sufficiently advanced technology is indistinguishable from magic'.

One of Sagan's early claims from the era of Vietnam and Watergate was that receipt of a signal would not only show the possibility of surviving technological adolescence but might also provide information to help us do the same. Since scientific thought is entrenched in the historical and cultural biases of the scientists involved, not to mention the increasing use of models and metaphors at the cutting edge, how easy would it be to understand even scientific concepts from a culture probably millennia more advanced than our own? Even if we could decipher alien scientific data, the next obvious problem is might we inadvertently destroy ourselves via some form of industrial accident, or developments in the $1.2 trillion per annum arms race, brought about by precipitant use of advanced technology? This displays another danger of SETI research: the wide-ranging but pointless speculation in lieu of hard evidence. Until we receive a message, all such conjecture is only of use to acknowledge our own hopes and fears. Even the mildly optimistic notion of extra-terrestrial contact bringing wonder or enchantment to humanity could be countered by slow translation progress in this era of the 140-character Tweet. When the news reports over the ALH 84001 meteorite were at their height in the mid-1990s, I remember work colleague telling me she was heartily sick of hearing about it. Clearly one person's mysterium fascinans (as Stephen Jay Gould might have phrased it), is another's mind-numbing tedium!

How long we will keep listening for is also open to question. If after a few more decades of concerted effort we have still not found definitive evidence, one possibly positive outcome might be the increased promotion of eco-awareness via the obvious rarity of own biologically-active planet. But current estimates suggest we have so far undertaken only about one hundred-trillionth of the radio coverage deemed necessary for a thorough search. It will be at least decades before we can afford to build even robot craft capable of travelling interstellar distances in reasonable spans of time, so until then we have little choice but to rely on our various types of receiver. So why bother at all? For the comparatively small sums involved, there's not much else that could provide such an astonishing potential return. As for the pessimists out there, I can offer nothing better than Monty Python's Eric Idle: "And pray that there's intelligent life somewhere out in space / 'Cause there's bugger all down here on Earth!"

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