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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