In search of space beavers

Chemistry & Industry, 19 July1999

Planetary dreams: the quest to discover life beyond Earth
Robert Shapiro
Chichester: John Wiley & Sons
Ppix+306, 22.50, ISBN 0 471 17936 1

Not many people now remember, but life was discovered on the Moon in 1835. Reports in the New York Sun told how the eminent British astronomer Sir John Herschel, equipped with a revolutionary telescope that used 'hydro-oxygen reflectors' to focus on objects as small as 18 inches across, had observed bat-winged men, unicorns, diminutive bison and bipedal beavers amid the verdant valleys of the Mare Faecunditatis. The US was transfixed as news of each startling discovery was unveiled.

Extraterrestrial life was discovered again in 1996, this time on Mars. A respected team of US researchers at the Johnson Space Center in Houston and at Stanford University in California identified fossilised bacteria and organic molecules characteristic of life in a meteorite recovered from the Antarctic tundra. It had landed there 13,000 years earlier after being smashed out of the Red Planet by some mighty impact. This time the whole world was watching as NASA trumpeted the discovery in a series of press conferences.

These two incidents, separated by 160 years of scientific progress, vividly demonstrate mankind's desire to prove that he is not alone in the universe - a desire that can reach quasi-religious intensity in its ability to override reason. We may safely mock our forefathers for accepting the 1835 hoax - or legitimate satire on contemporary scientific discourse as its perpetrator, struggling journalist Richard Adams Locke, preferred to call it. But the 1996 incident is still too close for comfort for many who jumped aboard the NASA bandwagon.

The jury is still out on the Martian meteorite. The general consensus now appears to be that none of the phenomena suggestive of life are necessarily biological in origin, although the meteorite does contain an unusual concentration of such phenomena. Still, few researchers are as optimistic now as they were three summers ago.

At that time, microbiologists and geologists were appalled by NASA's haste in sensationalising its 'discovery' before the work could be peer-reviewed. The fact that the announcement coincided with both the agency's funding review and the release of alien-invasion movie Independence day was, of course, pure chance. Global telecommunications meant that news of the Martian meteorite flooded the world even before collaborating researchers had been informed. This was an ironic contrast to the 1835 incident, where the lack of instant global communications helped prolong the hoax by preventing anyone from contacting Locke's declared sources - Herschel, who was observing in South Africa at the time, and the Edinburgh Journal of Science, which was actually defunct.

The two incidents also demonstrate the lowering of ambition of those looking for life beyond Earth. Except for some fervent believers, few now expect to discover a fully-functioning alien civilisation on our cosmic doorstep. If life is discovered elsewhere in our solar system - the only place to look until we come up with faster-than-light travel - it is much less likely to resemble Locke's civilisation of space beavers than something you would clean from the back of the fridge.

While Planetary dreams does cast an eye over some of the more fanciful possibilities, the emphasis is on the sludge. The author, New York University chemistry professor Robert Shapiro, may be searching the outer reaches for signs of life but his feet are firmly on the ground.

Even if we find only a few strands of alien seaweed clustered around a hydrothermal vent beneath the frozen oceans of Europa, it will show that life is not unique to Earth, Shapiro emphasises. Given the apparent improbability of the chemical mush left over from planetary formation spontaneously assembling itself into self-propagating biological assemblies, that would be a vital discovery.

Throughout the book, Shapiro treats with courteous contempt those scientists who believe that life on Earth is a statistical fluke, akin to dropping a sack of Meccano down a flight of stairs and watching the pieces assemble themselves into a functioning robot. The vast improbability of such an event is balanced only by the vastness of the universe. This group, which Shapiro names the 'sour lemon school' in response to their emotional tone, holds that life is the result of an entirely natural, but highly unlikely, process of molecular collision.

The discovery of life elsewhere in the solar system would not necessarily prove the sour lemon school wrong: it could have had a common origin with life on Earth and been propagated by meteor, for example. But it would certainly weaken their case.

Nor would such a discovery necessarily convince a second school of thought - the creationists, who hold that life was created by divine intervention. In one memorable encounter described in this book, Shapiro visits the Museum of Creation and Earth History in California and is told that if life is discovered on Mars or Europa, then obviously God created that as well.

Shapiro himself subscribes to a third school of thought, that of the 'life principle'. He believes the laws of Nature include some principle that favours the generation of life as part of some greater scheme of cosmic evolution. Stated in such bald terms, this conjecture may seem as crackpot as the other two schools do to their opponents. The joy of Planetary dreams is in watching as Shapiro eloquently states his case.

He makes no bones as to the weaknesses of his philosophy, the greatest being our lack of understanding of how life originated on our home planet. But he achieves the rare feat of making the reader want him to be proved right.