An overview of the search for intelligence on distant planets.
In his first book, Cooper, science writer and editor of Astronomy Now, emphasizes that the universe teems with extrasolar planets, but evidence of life remains out of reach, to the frustration of almost everyone, including scientists working at the Search for Extraterrestrial Intelligence Institute, which has been looking for more than 50 years. The sci-fi trope of the evil alien has largely fallen out of fashion. From the hit movie ET to Congress, which killed SETI funding in 1993, almost everyone today agrees that intelligence on distant planets is worth searching for. Traveling the world, Cooper chronicles his interviews with scientists and scholars who discuss how to do it and what we might find, if anything. Throughout, the author is free with his own opinions, and there is no shortage of surprises, the first of which is the chapter on altruism. Why should extraterrestrial visitors have benign intentions? “Our present beliefs about alien civilizations are built on the basis of taking the best parts of our humanity and extrapolating them into the future,” writes Cooper. “It’s an easy trap to fall into.” He reminds readers of the disastrous history of human explorers who encountered strange cultures. Do smart aliens even exist? Experts can’t decide if—like an elephant’s trunk or giraffe’s neck—intelligence is a chance byproduct of evolution or a regular feature such as eyes, limbs, or wings. Cooper recounts the debate between “rare Earth” experts who believe we may be unique with those who disagree, but it remains an area of pure (and frustrating) speculation. Discussions on technical aspects of searching contain more satisfying answers. Provided distant aliens possess transmitters an order of magnitude more powerful than ours, today’s receivers can detect the signal. Sending an actual message—as opposed to a mere signal—requires vastly more power.
“Are we alone in the universe?” has no answer yet, but Cooper delivers an enlightening exploration of the question.