Is Earth Exceptional? The Quest for Cosmic Life

Astrophysicist Livio (Galileo and the Science Deniers) teams up with Nobel Prize–winning biochemist Szostak for a probing if dense inquiry into the origins of life on Earth and the search for life in the cosmos. Suggesting the first “protocells” likely formed from RNA, the authors provide a technical overview of the chemical reactions that would have been required to create the nucleic acid from inorganic materials, explaining, for instance, that cytosine, an “information-bearing chemical unit,” could have arisen from interactions between cyanamide and ribose. The authors contend that the physical processes that transform nucleotides, amino acids, and other compounds into the building blocks of life are most likely to occur in locales rich in iron and phosphates with “wet-dry and freeze-thaw cycles,” making “hot springs in volcanic areas and craters created by asteroid impacts” the most likely candidates. Such findings have guided where scientists look for life beyond Earth, the authors write, noting that the Saturn moon Titan is among the most promising candidates because it has “stable seas and lakes, rainy seasons, and even an Earth-like cycle of liquids on its surface.” The deep dive into chemical reactions can be tough going, but those who stick it out will gain a firm understanding of what scientists are looking for on potentially life-bearing planets and moons. This challenges and fascinates in equal measure. (Sept.)