The Eerie Silence: Are We Alone in the Universe? [Hardcover]

The search for extra-terrestrial intelligence, or SETI, is in a rut. That is Paul Davies's message in `The Eerie Silence - Are we alone in the Universe' - a thorough taking stock of the programme started by Frank Drake in 1959 to search for alien radio messages from outer space.

Davies wants a rethink from scratch, where we shake off the blinkers of anthropocentric thinking and question exactly what we should be looking for. Listening out for a direct radio message is fine, but lets extend the search to include more subtle evidence of alien legacy and the very origin of life.

ET has indeed been strangely quiet, and for Davies two rather extreme explanations for that are providing signposts to a `New SETI'.

Under the first option, we have to accept that life on Earth was born of a series of events so incredibly flukey they will never be repeated. Under the second, we face the chilling prospect that intelligent life pops up quite frequently, only to develop a propensity for technology fueled self-destruction.

Holding out hope for a middle way, and putting speculation over self-destructing aliens aside, Davies argues there is a raft of solid science we could be getting on with to better understand the scarcity of life. Those up for the task (and skilled enough to secure funding) will enter a field of polarised opinions and a paucity of hard evidence. The prize? - possibly the final word on the question of whether life is ubiquitous in the universe - a `cosmic imperative' - or that you and I here on Earth are a one-off, somewhat lonesome, rarity.

We should still listen for radio messages, says Davies, enthusing over SETI's groundbreaking Allen Telescope Array (ATA) of radio telescopes; but the emphasis should be on searching for new types of evidence of intelligence, both in space and closer to home - on Earth in fact.

If we can show life on Earth started independently more than once - a second genesis if you like - the fluke theory is destroyed and the prospect of life existing on the billion or so Earth-like planets in our galaxy increases immensely. Once life has started, there is pretty much universal agreement among scientists that Darwinian style evolution will, environmental factors willing, take over to produce complex life forms and probably intelligence and consciousness. Second (and third and fourth..) genesis life forms could be living alongside us today, unrecognised as a microbial 'shadow biosphere' - the holy grail for researchers now culturing candidate samples from Mono Lake in California. Or we might find tell-tale markers of an extinct second genesis in geological records that we have seen but incorrectly interpreted. With so many work areas highlighted as candidates for inclusion in New SETI, a problem for potential researchers could be deciding where to focus their application. Presumably Davies is taking calls.

Moving from Petri dish to telescope dish, Davies believes our pre-conceptions of ET in space are causing us to define too narrow a target there also. Any intelligent biological life, he says, will quickly transition to an intellectually superior machine form having nothing in common with Homo sapiens and little to gain from interstellar chit-chat.

Or the aliens may have launched beacons that ping data packets only once a year. Or they may have sent probes - monolith fashion - to lurk around our solar system, programmed to spring to life when we learn to think up to their level. The point is we will only detect this kind of activity if we specifically look for it.

In his most futuristic speculation, Davies envisions life evolving into a quantum computer - an extended network of energy floating through space, amusing itself solving complex mathematical doodles. The implication of course, if such `beings' exist, is that we are headed in the exact same direction. How do you fancy being a node in a pan-galactic thought matrix?

Among other thought-provoking revelations, we learn the Earth has for billions of years been happily swapping rocks, possibly with primitive life aboard, with other planets in the solar system - including Mars. That makes the potential discovery of life on that planet important, but not necessarily a game-changer for SETI, as Martian and Earth life could share the same unique origin.

Davies puts SETI into historical context on a quirkier note, recounting how the mathematician Karl Gauss, as early as the turn of the 19th century, planned to signal the Martians using huge shapes cut out of trees in the Siberian forest.

There is an implicit appeal in The Eerie Silence for scientists from different disciplines to work together on SETI and astrobiology - maybe a guiding principle for New SETI? Astronomers, biologists, geologists, engineers, astro-physicists and cosmologists all have a role in the search - as do non-scientists.

That also holds true for the post-detection task-group Davies leads, set up to advise an appropriate response in the event ET finally calls. In a chapter devoted to the implications of `first contact', he asks how various groups: from the media, through politicians, the military, and religious believers might react. If we receive a targeted message, we should certainly think carefully about the reply. But that we already send the occasional burst of blindly targeted radio messages into space is a positive in Davies's book; at least it makes people think about science, humanity, and what in our culture we value. Religion, and particularly Christianity, Davies believes, will struggle to reconcile dogma with the existence of intelligent aliens.

In his wind-up, Davies keeps all options open as to the chances of a positive outcome for SETI. But on balance, hardcore enthusiasts of radio SETI in particular may well find the The Eerie Silence a bit of a downer. Likewise, those looking for evidence to support more philosophical ideas around nature favouring life, or the existence of a life principle buried in the physics and chemistry of the universe - themes Davies has arguably been more sympathetic to in previous works - will be disappointed as he rejects each in turn.

To its credit, The Eerie Silence is as much about human motivations and psychology as it is about research and radio antennae. A chatty narrative with frequent episodes of self-examination strikes chords with thoughts and feelings most of us will have had: like the need for a sense of self, and a yearning for meaning. The search for ET is very much the search for what we are, what we may become, and what `it' all means. A cliched theme maybe, but well supported here with relevant facts and reasoned speculation. Davies's talent for projecting rock-solid scientific rationalism while not (entirely) closing the door on other perspectives has produced an absorbing read.

Over the years I have read many of Paul Davies' books. He continues to write with great clarity and is adept as ever at explaining often complex concepts in ways that are relatively easy for a layman such as I to understand. I was always intrigued by science at school but struggled with physics and chemistry. I always keep an eye out for any new books by this, and a handful of other science writers - if only there had been as many good 'popular science' books published when I was a teenager struggling to understand the intricacies of physics and chemisty (late 60s/early 70s). This is a very different book as it is aimed at making sense of the SETI project which most people know from the novel 'Contact', and the film of the book, as well as the opening sequence of 'Independence Day'. It is an enjoyable and insightful account of how the search for extraterrestrial life has evolved over the last 50 years and where it is likely to be headed in the future. The book makes you appreciate just how vast the universe is and, possibly, just how rare life may actually be - or at least life that we might recognise. It's a thoroughly good read.

As well as being a history of SETI, 'The Eerie Silence' is also a passionate defence of the organisation. To me, Paul Davies' prose carries with it an almost plea-bargaining air of hopeful self-preservation. SETI has come under a lot of fire recently; especially sceptical commentators like to label the project as being an embarrassing white elephant of the science world - after so much money and no results, what's the point? There's also the cynical and somewhat prevailing sentiment that searching for alien life is nothing more than pseudoscience; the stuff of immature sci-fi novels.

However, by far the most damaging (and popular) criticism of SETI is a kind of economic determinism, which argues that if SETI is someday successful in detecting a non-terrestrial, artificial radio transmission, there will likely be no practical, financial or economic gains from doing so. High monetary input with no monetary yield does not make for valuable investment. Concordantly, SETI has suffered from substantial funding cuts in recent years. Of course, being the liberal student of the arts that I am, I take issue with the notion that all human endeavour should be geared towards a financial end-product. Whatever happened to finding value in the journey? Or striving to achieve something not because it carries a large financial incentive, but because it's incredibly difficult and challenging? The frontier spirit, Davies argues, is intrinsic to human experience, and it's a shame that SETI, as endeavour, is no longer considered viable purely because it carries no fiscal (or in some cases military) guarantees. If the current funding trend continues, then SETI will soon be entirely dependent on benevolent private donations: hardly the stable bedrock required by long-term scientific enquiry.

Drawing the reader's attention to the many criticisms of SETI is risky business, but Paul Davies provides convincing and intelligent rebuttals to all of these. His determination to present SETI as a serious methodical pursuit rather than the imprecise hobby child of UFO obsessed sci-fi dorks is commendable, if a tad unnecessary.

Yet the article of contention with which the book is most concerned is scientific, namely: the Fermi Paradox. The paradox's namesake Enrico Fermi became famous for espousing a form of evidential scepticism about SETI: "where are they?" is how he succinctly voiced his concerns. Basically, the Fermi Paradox can be summed up thus: if the universe is so old, and so big and so full of so many trillions of stars, then why is there absolutely no evidence of alien life anywhere? (okay, so it's not technically a "paradox" - but hey, they're only scientists!). It sounds simple enough, but the Fermi Paradox has so far proven to be the foremost prodigal spanner in SETI's otherwise well-oiled works. If the universe is metaphorically teeming, then why does it seem to...empty? There are two possible explanations: either there's something fundamentally wrong with SETI's search methodologies, or we really are alone after all.

Paul Davies plumbs for the former. 'The Eerie Silence' argues that it's time to stop pinning our hopes on targeted alien radio broadcasts and to begin looking for any signifiers of intelligence and life; no matter how alien they may seem to us.

He begins at home, with the concept of a `shadow biosphere'. Put simply, this is the theory that instead of spawning just once on Earth, life may have begun twice, or three times etc... If provable evidence of a `second genesis' could be found (for example, microbes with left-bonding amino acid systems, as opposed to the right-hand amino bonding of all known life) then the probability that life exists elsewhere in the universe would be elevated to a near factor of 1 (100%). If life spawned twice on one planet, then the chances of it happening anywhere else would be much, much higher. Serious experiments to find terrestrial life from a `second genesis' are currently in the planning stages in America. Aliens among us indeed.

Next Davies examines the theory of panspermia, which puts forward the mind-boggling notion that life on Earth was `seeded' from elsewhere in the universe, such as by hyperextremophile microbes hitching a ride in meteorites. Maybe life was bio-engineered by intelligent, unknowable aliens. Self-replicating probes that plant life on habitable `target' planets are also considered by Davies.

His discussion of the potential types of alien life gets more and more interesting as the book progresses. The size and sheer weirdness of Davies' ideas increases exponentially chapter by chapter. By the end of The Eerie Silence, the book is carrying with it all the usual mind-boggle sentiments of high-concept science fiction writing. People who know me also know that I have an irritating tendency to geek-out about this kind of stuff, but I defy you to read The Eerie Silence and say it isn't interesting. I devoured it - the writer has a gift for imbuing his ideas with a sense of wonder and scale. Some of the thoughts presented within filled me with a sense of, well... a kind of readerly vertigo, as if I were standing on the precipice of something vast and unknowable and ancient. Davies clearly revels in immense ideas such as post-biological intelligence, stellar engineering and terraforming:

"I think it very likely that biological intelligence is only a transitory phenomenon. If we ever encounter extraterrestrial intelligence, I believe it is overwhelmingly likely to be post-biological in nature."

Davies even suggests that the best way to find E.T might be to look for evidence of galactic mega-structures, such as Dyson spheres (massive grids of satellites constructed around entire stars to absorb energy) and Matrioshka brains (super-computers so big that they are built as shells around back-holes, and harness energy from within). These super-structures would emit unmistakable infra-red signatures, and so would be easy to detect.
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Stylistically, Davies is a man after my own heart; he employs frequent parenthetic digressions (that is, stuff in brackets) to express several ideas at once, as well as to make sometimes pithy and wry comments on whatever topic is at hand. Structurally, however, the book has some problems. Barely a page goes by without Davies using the phrase "more about this later". While sometimes tantalising, more-often-than-not I found this sort of referential aside to be irritating, drawing attention to the fact that the book's chapter-structure probably isn't optimal.

'The Eerie Silence' isn't unadulterated popular science either. For the polymaths among you, it's also possible to read it as a strikingly philosophical work. Davies takes time to explore such frighteningly eschatological theories as the so-called `heat death' of the universe; an end-game scenario in which all entropy reactions have expired, leaving no thermodynamic energy to sustain life, matter, motion, anything. The concept that the universe is on a slow, unstoppable march towards nothingness reads like an astrophysics expression of Nietzschean nihilism.

But while I can't fault his science, Paul Davies' understanding of history leaves something to be desired. Davies argues that modern science only came around because Judeo-Christian society has a kind of oneness about it which is perfect for spawning scientific method. I respectfully disagree. Correct me if I'm wrong, but my impression was that the rise of mass-organised religion in Europe culminated in the so-called medieval `dark ages' - a period of retarded scientific progression that was finally transcended by the Renaissance, when radical thinkers began to rediscover pre-Christian modes of enquiry (hence `neo-classicism'). It wasn't Judeo-Christian ideologies that lead to the development of modern science, but ancient Greek philosophy, which insisted that the universe isn't random and absurd, but logical, knowable and ordered. That's my two cents anyway; but what do I know?

This is a minor niggle, however; on the whole The 'Eerie Silence' is complexly wonderful, eminently readable and very accessible (hell, if a certified science reprobate like me can understand it, anyone can). There're a few frivolous passages that engage with aliens in pop-culture (such as basic (though admittedly comic) reviews of Contact and Independence Day), which do nothing to squash SETI's image as an organisation populated by sci-fi loving geeks (the dust jacket's author photograph also doesn't help matters - a black and white snap of Davies in all his bi-focal, thick-rimmed, bowler haircut glory). But the best way I can describe The Eerie Silence is to tell you that it's relentlessly, unremittingly interesting.

And unlike most popular science, this is a humanising and encouraging work. A more cynical reading than mine might label 'The Eerie Silence' as a book that romanticises science. But SETI is an on-going endeavour, and it's admirable (and refreshing) that Davies stresses the value of exploration, curiosity and human progress outside of any financial context. There is science here, there is maths here; but it's also a book with an identifiable, emotional heart. Finally, Davies takes great pains to stress that SETI may never succeed; there are so many variables and so much is unknown that some critics don't even think of it as true science. But Davies insists that SETI press on - "The probability of success is difficult to estimate; but if we never search, the probability of success is zero". It turns out that the real sine qua non of SETI isn't money, but hope.