Life on Earth and in Space
摘要
In this third chapter, we embark on an extensive exploration of the tantalizing prospect of life beyond Earth. Our journey commences with an examination of the Viking life-detection experiments conducted on Mars, marking humanity's inaugural attempt to uncover signs of extraterrestrial life on a planetary surface. These pioneering endeavors lay the foundation for our subsequent discussions as we delve into the intricacies of defining life and the formidable challenges associated with substantiating its existence. Furthermore, we scrutinize the critical concept of habitability and its pivotal role in assessing the potential for life to thrive in diverse environments. Additionally, we provide insights into the diversity of biological life that has evolved on Earth, and in particular, early life and extremophiles, drawing parallels to envisage the possible forms of life that could inhabit ocean worlds. Through an in-depth analysis of these key themes, we construct a comprehensive framework which we then apply to the various moons and dwarf planets we investigate throughout this book, asking ourselves if life could arise in such places.