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Alien life by Barry Parker, Plenum Press, £16.95/$27.95, ISBN
0306457954

HOPE died in the desiccated dust of the Sea of Tranquillity—or so it
seemed. The Moon, the only body in the Solar System we had a realistic chance of
reaching, was a dead world. What’s more, it has been dead for billions upon
billions of years. This single appalling fact was at least as important as the
hollowness of America’s victory over the Soviet Union in provoking the end of
the Apollo programme and turning the public off space in a very big way.

What an astonishing turnaround we have witnessed in the past few years.
Planets—or at least the ghostly fingerprints of planets—have been
found in the light of a dozen nearby stars. Frozen water has even been found on
the Moon.

Arguably the most significant discovery, however, has been made not in space
but here on Earth. For the organisms found eking out an existence deep in the
planet’s crust— and around blisteringly hot vents gushing toxic chemicals
onto the seafloor—have dramatically changed our ideas about life in
extreme environments. Suddenly, it is not out of the question to consider the
possibility of life in the caves of Mars, the giant ocean of Europa or the
methane seas of Titan.

Not surprisingly, all this excitement has prompted a spate of books on
extraterrestrial life. What are we to make of this latest one? I would like to
be able to report that Alien Life is a book that fires the imagination.
It isn’t. What it does offer is a workmanlike account, thorough and accurate,
but frankly not a very exciting read.

Of course, this style may have been forced on Parker because he had to
squeeze such a huge range of material into such a slim volume. For he covers
everything from the development of life on Earth to the prospects of finding
life on Mars; from detecting planets orbiting distant stars to possible ways of
travelling between the stars; from SETI, the Search for Extra-Terrestrial
Intelligence, to UFOs.

In places, Parker does a particularly good job. For instance, it is no mean
feat to communicate in only a few pages the reasoning that led Crick and Watson
to the structure of DNA, and at the same time give a flavour of their
larger-than-life personalities and the sheer barefaced cheek that won them
biology’s ultimate prize. Parker also deserves praise for his captivating
account of the incredible journey of the Martian meteorite ALH84001, a rival to
The Odyssey itself.

However, some topics, such as Fred Hoyle and Chandra Wickramasinghe’s idea
that life was seeded from space, get short shrift from Parker. The irony is
that, having quickly dismissed Hoyle and Wickramasinghe’s ideas, Parker goes on
to point out how puzzling it is that life got going on Earth almost the instant
the planet was cool enough. Some suggest that this must mean that the step from
nonlife to life is an easy one, even though scientists have failed miserably in
their attempts to duplicate the feat in the laboratory. Whatever you think of
the idea that life was seeded from space, it at least provides a solution to
this one puzzle. And if there exists a mechanism for spreading life between the
stars, it need arise only once in the Galaxy to end up everywhere. Life can be
both incredibly difficult to get going and widespread.

I don’t want to dismiss Parker’s book just because it didn’t excite me. He
writes succinctly and packs the information in. Anyone who knows little about
the search for extraterrestrial life and would like a broad-brush introduction
will find this a good overview.