LIFE OUT THERE

A sweeping look at the many possible places we can search for signs of extraterrestrial life, from distant galaxies to our own back door. White (Isaac Newton: The Last Sorcerer, 1998, etc.) ventures first to the planet we all think of when casual conversation turns to extraterrestrials: Mars. He contrasts the recent discovery of primitive microorganisms on a Martian meteorite with the results of tests performed by the Viking spacecraft that landed on Mars in 1976. More important for the uninitiated, he gives detailed reasons why this rock is known to come from Mars and what evidence of “life” was found on it. He doesn—t let the reader progress far before asking and answering the more fundamental question, What is life? White continues with a laundry list of every planet and moon in our solar system, examining if life could exist on each. He explains how planets circling other suns were not detected until this decade and that the search for radio signals from elsewhere in the galaxy is in its infancy too. Although travel to planets in other solar systems would take thousands of years using current technology, this in no way diminishes White’s enthusiasm for the possibility of space travel using as-yet-theoretical means of propulsion. Once we get to other planets, what would life there look like? White emphasizes the similarities we would have with such life, arguing that life anywhere would use RNA, the same building blocks as on Earth. Life would also, he contends, require the existence of water, which may have been present on Mars in the distant past. Finally, there’s the intriguing notion that life on Earth could actually have been “seeded” by microbes from another planet. Are we, in fact, all Martians? Abundantly optimistic. Covers the gamut of current scientific research on the possibility of life elsewhere in our solar system and beyond. (17 illustrations)