Life as We Do Not Know It

September 19, 2005
Ward's Rare Earth
(coauthored with Donald Brownlee) suggested the unlikelihood of our finding an alien race as complex and evolved as humankind; if such beings exist, they're too far away for us to make contact with. But what about more basic forms of life right here in our solar system? Ward, an investigator with NASA's Astrobiology Institute, believes researchers might be taking the wrong approach by looking only for earthly DNA-based life forms. Truly alien life, he argues, might have completely different origins; even Earth has untold numbers of viruses composed entirely of RNA, and scientists have created similar genetic material in laboratories, so who's to say silicon-based life-forms are impossible? After introducing readers to the building blocks of life and the new ways they might be arranged, Ward speculates on what types of microbes we might find on other planets and their satellites. He recommends that future manned space expeditions include paleontologists and biochemists to follow up on suggestive evidence collected by space probes. The science is neatly laid out, and readers willing to follow his daring, scientifically based speculations will find their imaginations spurred.