An astrobiologist and planetary geologist delineates the development of life on Earth and then makes the leap into “life” elsewhere in the heavens.
In her debut, Preston proves to be a jaunty, upbeat, and highly curious writer. “Today,” she writes, “astrobiology works tirelessly to address the compelling mysteries surrounding extraterrestrial life, while embracing the study of the origin, evolution, distribution and future of life on this planet.” That is as neat a summary of this book as one will get. Though she admits that understanding the beginnings of life “isn’t pretty and is chemistry heavy,” she goes on to spell things out clearly, walking readers through physics, chemistry, astronomy, biology, molecular biology, ecology, planetary science, geography, and geology. When she is walking on thin ice, she makes note (“let’s admit this up front—we do not know exactly how life got started”), covers what we do know (“the primitive Earth was wrapped inside a blanket of dense burning clouds and remained shrouded in darkness”), and makes some speculations. The author examines our bombardment from comets and icy bodies and offers a lucid discussion of the mind-stretching marvels of organic chemistry. She also writes engagingly about the importance of auroras, plate tectonics, and glaciation as well as the possibility of artificial intelligence becoming an existential threat. Researchers are constantly searching for planets similar to Earth, within the Goldilocks Zone, “a not-too-hot, not-too-cold orbital band around a sun where life-giving water can be liquid.” However, outside of this habitable zone may exist life forms beyond our ken, “extremophiles” and “polyextremophiles.” The best to consider are tardigrades, or water bears, which can survive prolonged blasts of radiation (as experienced in outer space), bottom-of-the-ocean pressure, and temperatures from minus 459 degrees fahrenheit to 300 degrees.
A solid, absorbing background to what makes life possible.