It's likely that humans are far from alone

First Contact

Scientific Breakthroughs in the Hunt for Life Beyond Earth

By Marc Kaufman

Simon & Schuster. 224 pp. $26

Reviewed by Fred Bortz

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.

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.