The Wall Street Journal recently asked me to review a new book called First Contact: Scientific Breakthroughs in the Hunt for Life Beyond Earth. Astrobiology is a tricky subject to write about these days. It’s intensely exciting, despite the fact that its main object of study–life on other planets–has yet to be discovered.

I’ve given some thought to how we journalists should cover such a paradoxical science. We shouldn’t dismiss it outright, because astrobiologists have discovered fascinating things about life here on Earth, even if they have yet to find aliens. Yet we shouldn’t feel obligated to pump up every claim about the possibility of life elsewhere. We should be content to paint a portrait of the scientific process–including the intense debates–in all its gorey detail.

By this measure, I don’t think First Contact works. The author, Marc Kaufman, declares at the outset of the book that “before the end of this century, and perhaps much sooner than that, scientists will determine that life exists elsewhere in the universe.” Not whether life exists, mind you, but that it exists.

I don’t think he backed up that bold claim. Instead, he pumps up intriguing, but inconclusive, evidence. He portrays the scientists who made claims for arsenic life, for example, as bold, out-of-the-box thinkers, and criticisms as little more than the rants of bloggers. He’s not alone–on Thursday,Time picked a member of the arsenic life team as one of their 100 most influential people of 2011. But these portrayals don’t match the reality of the arsenic life saga. I find the manufactured dichotomy between the supposed mavericks and the mean-spirited critics to be particularly off target. Remember, a lot of the critics of arsenic life are astrobiologists themselves.

For a better example of how to embrace scientific debate, check out Richard Panek’s The 4 Percent Universe: Dark Matter, Dark Energy, and the Race to Discover the Rest of Reality which I reviewed for the Washington Post in January. Panek doesn’t shy away from the intense competition and bad-mouthing that cosmologists engaged in as they rushed to establish the deep mystery of the universe. It’s a rich story that doesn’t shy away from the messiness and uncertainty that the big questions in science inevitably create.

Originally published April 22, 2011. Copyright 2011 Carl Zimmer.