Mr. Universe

Keay Davidson Examines The Scientist Who Brought Wonder To The Cosmos.

Carl Sagan: A Life, by Keay Davidson (John Wiley & Sons, Inc.) Cloth, $30.

CARL SAGAN IS three years dead. And while he claimed never to have said it, his oft-repeated shibboleth "billions and billions" is about all most remember. Keay Davidson's Carl Sagan: A Life therefore seeks to recall the scientific translunary to a forgetful public.

Sagan no doubt would have been the first to point out that indeed his was but one life -- possibly influential during its ephemeral existence, but certainly insignificant amid the vastness of time and space.

In this critical biography, Davidson explores the duality of Sagan's personality and its effects on his scientific career and personal life. Davidson effectively advances the notion that Sagan's duality was not only extreme, but the key to understanding his diverse contributions to science and humanity.

In the early chapters, Davidson chronicles Sagan's adolescent life, his fascination with the stars and the possibility of extraterrestrial life. Sagan was one of many youths caught in the thrall of the UFO fever which swept the nation in the 1940s. Though in college Sagan would eventually become one of the most outspoken critics of UFOs, Davidson argues convincingly that Sagan's incipient immersion in the world of science fiction made a strong impact on his character. It allowed him to convey -- most notably in his TV series Cosmos -- a wonderful, near-magical aspect to science that until then had been totally absent.

Of course, "magical" is not a word most scientists would like the public using to describe research. In fact, it should be said that Sagan did more to emphasize science's wonder and dispel its magic than any scientist who ever turned his nose up at what he perceived to be Sagan's absurd pontifications. Sagan, above all, championed the "knowable," that which could possibly be disproved -- the acid test of "real" science. He felt that if the public was aware of the wonder of real science, they wouldn't need the superstitious trappings of pseudoscience (e.g. ghosts, UFOs, astrology), which he considered the bane of progress.

Sagan himself expounded some fantastic hypotheses during the course of his career. Some of his wilder ruminations concerned the possibility of life on the moon and the potential existence of polar bear-sized creatures on the surface of Mars (well after satellites had revealed the Martian surface to be a cratered expanse of rock and dust, far from what we Earthlings would call habitable). On the other hand, Sagan was correct in his support for a "greenhouse" model of Venus, where layers of clouds trap the sun's heat, resulting in an infernal surface temperature of approximately 500 degrees C.

His colleagues may have scoffed, but Sagan's methods jibe well with the late scientific philosopher Karl Popper's view that "science advances by unjustifiable, exaggerated guesses followed by unstinting criticism." Perhaps unconsciously, Sagan followed this ideology throughout his career. Whatever can be said about some of his wilder speculations, he always followed the data and used "unstinting criticism" in his quest for truth, even when it ran contrary to his hypotheses.

By the 1980s, owing mostly to Cosmos, Sagan had reached celebrity status. But celebrity, as they say, comes with a price. For Sagan, that price was the prestigious National Academy of Sciences (NAS), who turned down his membership bid in 1992. Though he had many supporters within the ranks of NAS, several vehement attacks on his career swayed members.

Davidson's description of this event is thorough. He had access to a letter penned by NAS member and Sagan's first wife Lynn Margulis, which describes in detail the proceedings, and what she perceived to be the jealous motivations of Sagan's detractors. In fact, her letter stands on its own as a trenchant condemnation of NAS, its myopic constituents, and the elitism that is so often concomitant with scientific specialization.

Davidson, however, does not hold Sagan blameless in his struggles. Especially in his personal life, Davidson describes an ultra-logical, self-centered careerist. Sagan's fascination with the stars left his first marriage to die of neglect. He is a portrait of a man with his head quite literally in the stars, his feet barely tethered to Earth.

It was not until he met his third and final wife, Ann Druyan, Davidson posits, that Sagan began to attend to individuals, not Humanity writ large. In his final chapters, we see a marked humility descend upon Sagan, especially after his diagnosis in 1994 with myelodysplasia, a rare and fatal blood disease that would eventually claim his life.

With this biography, Davidson gives us a well researched look into the scientific accomplishments of a man many scientists regarded as a quack, and the personal life he kept largely hidden. Davidson forbears over-extending his reach on the theme of duality. His search for motivations and underlying meaning is almost always plausible. The book is packed with statements from colleagues and friends as well as rivals, not to mention one ex-wife (whose comments are surprisingly even-handed).

As an established science writer, Davidson to some degree handles NAS with kid gloves. He teases us with references to Karl Popper, but one senses that the similarities between Popper's and Sagan's ideologies, if explored, could have been used for a more forceful condemnation of the scientific elitism that railroaded Sagan throughout his career. Just the same, Davidson gives considerable ink to the backstabbing and lifelong grudges that are the ignominious hallmarks of the scientific community. Graduate students will relish these delicious descriptions. Also of interest are Sagan's brushes with notable coevals, including Isaac Asimov, Stanley Kubrick and Timothy Leary.

No one would have lamented the failed Mars Orbiter and Polar Lander more than Sagan. Failures like these he knew all too well. (Mariner 1's explosion in 1962, due to the omission of a single hyphen, is oddly redolent of the Mars Orbiter's loss due to the failure of its engineers to convert English units to metric.) Were he alive, he would be advising us, sagely and calmly, not to give up on space exploration.

Without conclusive evidence, we can still imagine that microbial life exists on Mars, in the tiny cracks between rocks or beneath the Martian surface. It's not polar bears, but the discovery of life -- any life -- on another planet would certainly be one of humankind's most historic events. That, to Sagan, was reason enough.