Scientists are finding ever more evidence that Mars and many other planets may support life.

First Contact

Scientific Breakthroughs in the Hunt for Life Beyond Earth

By Marc Kaufman

Simon & Schuster. 224 pp. $26

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Go into any fifth-grade classroom and you may encounter a future space alien.

Despite NASA's temporarily austere budget, 30 years from now, when those fifth graders are of prime age to be astronauts, NASA and other space agencies will probably be preparing to send humans to Mars. When those intrepid explorers set foot on the Red Planet, they will be alien beings from this world stepping out onto another.

They won't be the first space aliens from Earth. That title belongs to the Apollo astronauts of 1969-72. But as Washington Post science writer (and former Inquirer staff writer) Marc Kaufman notes in his new book First Contact: Scientific Breakthroughs in the Hunt for Life Beyond Earth, Mars is different from the moon in one particularly important aspect.

The moon is, and was expected to be, lifeless. The more planetary scientists study Mars, Kaufman writes, they find "ever more reason to conclude that Mars . . . has, or had in the past, most everything necessary to support life."

A 2009 discovery of methane gas in the Martian atmosphere, Kaufman notes, is strongly suggestive that Martian microbes live beneath the planet's surface today. "On Earth, some 90 percent of methane in the atmosphere is a by-product of living creatures, and biology has to be considered a serious candidate for the production of methane on Mars as well," he writes. "It could also be true that methane can come out of a geological process. But the alternative to biology would be almost as significant. Mars has long been considered geologically dead."

Kaufman is far from the first author to write about astrobiology, the science of extraterrestrial life. His extensive bibliography cites numerous others, including the path-breaking Rare Earth: Why Complex Life Is Uncommon in the Universe, by Peter D. Ward and Donald Brownlee. Conspicuously missing is one of Ward's later works, Life as We Do Not Know It: The NASA Search for (and Synthesis of) Alien Life, which would be particularly useful to readers looking for more scientific depth and detail.

First Contact: Scientific Breakthroughs in the Hunt for Life Beyond Earth
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What sets First Contact apart is its emphasis on the impact of astrobiology on the way humans see themselves in the universe. The discoveries of astrobiology are bringing about the full flowering of Copernicus' grand idea that demoted our planet from its central position in the universe.

Thanks to astrobiology, the human species and civilization may be about to suffer the same demotion. Astronomer Frank Drake is best known for his eponymous 1963 equation that estimates the number of advanced civilizations in the Milky Way galaxy. Drake's equation is widely accepted among astrobiologists, but the same scientists' individual predictions vary widely because the formula depends on a few factors that they vociferously dispute.

By Drake's reckoning, one of every 10 million planetary systems hosts a "technologically evolved" planet. With hundreds of billions of stars in the galaxy, that means there are many thousands of civilizations in the Milky Way alone. But given the vastness of the galaxy and the unknown lifetime of the average civilization, it's no wonder the set of projects collectively known as the Search for Extraterrestrial Intelligence (SETI) has not yet detected any sign of extraterrestrial intelligence.

In his closing chapter, Kaufman speculates about the impact that a confirmed SETI discovery would have on humanity, including how various religions are likely to respond. In earlier parts of the book, he lays the groundwork for that speculation.

He begins with an examination of extremophiles, terrestrial organisms that live in environments that are harsher than those on Mars or other potential habitats in the solar system. The implication: Life is an opportunistic phenomenon that "if given an environment even the slightest bit friendly, will find a way to adapt and survive."

He continues with the question of origin. Can biological molecules and life itself arise from nonbiological chemistry? Examinations of meteorites, exploration of asteroids and comets, and experimental simulations of conditions on ancient Earth (or Mars) suggest that biological molecules are prevalent in space, that biological activity can arise spontaneously, and that cellular structures and eventually complex organisms can emerge on a planet or moon, given enough time and a favorable environment.

First Contact: Scientific Breakthroughs in the Hunt for Life Beyond EarthThus prepared, Kaufman proceeds to Mars. With robots and eventually humans doing on-site research and with plans for sample-return space missions, neither he nor his readers would be surprised by the confirmed discovery of Martian life in their lifetimes.

"One genesis in a solar system and it could be a fluke," he writes. "Two geneses and suddenly life becomes more of a feature than an anomaly. . . . One small microbe for Mars, one giant leap for life in the cosmos."

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