The Living Cosmos: Our Search for Life in the Universe By Chris Impey (Random House, $27.95)
“There are infinite worlds both like and unlike this world of ours,” wrote Epicurus. That’s how astronomer Chris Impey begins his compelling investigation into the history of the search for extraterrestrial life. Starting with the Greeks and their philosophical inquiries, Impey traces the scientific work on the origins of life and the evolution of Earth and of distant worlds. He examines theories on the conditions required for biological life to arise and how likely it is that such life exists on other planets in our own or other solar systems. Impey asserts that water is a promising presence. In fact, NASA’s strategy has been to “follow the water.” That’s why Mars was an early object of interest and why Saturn’s moon Enceladus joined the list of possible life holders in 2006 when the Cassini orbiter spotted geysers at its south pole. Will we one day find other beings in the universe? Impey isn’t sure, but he does believe that science is the only tool that can discover them. As he puts it, “The debate over the existence of ETs might never be settled by observations, but it certainly can’t be settled without them.”