...But not as we know it

Review by Caspar Henderson of Weird Life: The Search for Life That is Very, Very Different from Our Own by David Toomey

Published in The Literary Review, May 2013

In 1832, while HMS Beagle was anchored off San Salvador, Brazil, Charles Darwin went ashore to explore. There he saw rocks that glittered, as if burnished, in the sun. Darwin hypothesised that the shining was caused by a thin coating of metallic oxides but could not account for how it had been made. The strange phenomenon has since been observed in many places around the world, especially in deserts, and is now called desert varnish. But its origin – whether the result of complex but non-living chemical reactions or a residue left by unknown living forms – remains utterly mysterious.

In the 181 years since Darwin stumbled across this enigma, our understanding and appreciation of living forms and life itself have deepened and expanded to a stupendous degree, perhaps beyond anything he could have imagined. But the great naturalist’s central insights have been triumphantly vindicated, and none more so than one expressed famously in the final sentence of On the Origin of Species in 1859: life has evolved from just a few forms or (as we now know) just one. Everything that lives on Earth shares a common ancestor.

Or does it? And what about life elsewhere? Such questions have been brought to particular public attention in recent months thanks to confirmation, by NASA’s Curiosity rover, that Mars at some point enjoyed conditions favourable to life, and indications that something rather strange may be thriving in the freezing depths of Lake Vostok in Antarctica. Could we be on the verge of discovering completely new biological forms?

David Toomey’s book is a fluent, bold and informative tour d’horizon of the latest thinking on these and other questions. It explores the frontiers of possibility, where ‘weird’ means anything that has an origin independent of the Last Universal Common Ancestor (LUCA) of all the earthlings we think we know. No such form has been discovered yet, but the literature of scientifically informed speculation is something rich and strange in its own right, and Toomey does it full justice.

The nine chapters of Weird Life cover a vast range of territory. Toomey starts with the discoveries over the last few decades of organisms called extremophiles, which live at scorching temperatures – some bacteria have been observed to reproduce at 121°C – and freezing ones of around -30°C. All of them, it turns out, are descended from LUCA, though many of them belong to Archaea, a domain of life first recognised only in 1977. Next, he reports on speculations about a shadow biosphere: a range of micro-organisms, perhaps vast in number, that could be living, so far unseen, alongside the microbes we know, but using radically different biochemical or molecular processes. Desert varnish may, some scientists believe, offer a tantalising clue to these organisms.

Serious scientific thought about life on other planets and moons goes back at least 350 years, to the brilliant Dutch physicist Christiaan Huygens. Actual exploration started in the 1960s with the launch of the first probes to Mars. Recounting these steps, Toomey traces how thinking about the very nature of what life is has evolved as researchers have considered ever stranger possibilities. He gives a ‘bestiary’ of weird life, including speculation about the forms it could take on Saturn’s moon Titan and Neptune’s moon Triton. These and other visions are fascinating but remain at the outer edges of plausibility: for all its sophistication, exploration to date has yet to yield definitive results for life, weird or otherwise, on Mars or anywhere else in the solar system. But this is only the beginning: even more extraordinary possibilities – conceptually alien but statistically probable – include life within the dense, relatively cool stars known as white dwarfs.

Toomey also surveys weird life in science fiction. He includes many of the familiar suspects, not least the silicon-based life forms encountered by the crew of the USS Enterprise and Fred Hoyle’s intelligent nebula, but I suspect I am not alone in having known nothing of the creations of Joseph Henri Boex, who in the 1880s under the pen name Rosny the Elder won the admiration of Jules Verne and H G Wells. Rosny’s prose is, apparently, execrable but his imagination is spectacular, giving rise to such phenomena as intelligent phosphorescence on Mars and trilaterally symmetrical extraterrestrial beings whose charms make them irresistible to at least one earthly admirer.

The final chapter of Weird Life moves into even stranger realms: speculation about the life that may exist in the multiverse – the 10500 or so universes that many physicists believe exist in different dimensions from our own. (If the multiverse does not exist we are still confronted with the possibility that our own universe is infinite in extent and contains an infinite number of exact copies of itself, as well as every conceivable permutation thereof.) Among the striking deductions reported by Toomey is that there are firm grounds for supposing that ours is not a universe especially fine-tuned for life. In fact, life could thrive just as well in universes lacking the ‘weak force’, one of the four fundamental forces of nature in our universe.

Toomey concludes that the search for weird life will be worthwhile even if it yields no results. Seeking to understand how things might be different requires us to look at what we think we know again. What was familiar becomes new and more remarkable. I couldn’t agree more.

Toomey is a superb explainer, firmly in command of the facts. Weird Life is remarkably comprehensive and written with considerable panache. You don’t need to be a specialist to enjoy it. But two important questions are scarcely addressed in this excellent book. The first concerns the possibilities for new forms of life arising from the rapidly developing field of synthetic biology: it may not be long before new organisms are born of an idea rather than an ancestor. The second concerns the kinds of changes humans may wreak upon themselves so that, while we may not become ‘weird’ in the fairly technical sense meant in this book, our descendants will nevertheless be significantly different. Many of the changes are likely to be biochemical and, it may be hoped, to the betterment of the species. But can we imagine moral and political transformation, such that our appreciation of the richness of life reaches a whole new level and we learn to become better stewards and companions of all beings, weird or otherwise?

Caspar Henderson's The Book of Barely Imagined Beings is published by Granta and Chicago University Press

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