The question of whether we are alone in the universe is one that has fascinated humankind since early times. But, as Carl Sagan once said, "The search for extraterrestrial life must begin with the question of what we mean by life". Astrobiologists today focus on the origins of the earliest and simplest life forms, bacteria and other single-celled organisms. Using Earth as a prototypical environment, they and other scientists tackle the question of life in the universe.
Beginning with the Big Bang and formation of the universe, this richly illustrated book explores the emergence of life on Earth and beyond. Monica Grady discusses the factors necessary for the development of microorganisms on Earth, including chemical building blocks like carbon and water as well as an atmosphere that protects from ultraviolet radiation. She considers the possibility of life on other planets in the solar system, describing the conditions and diverse habitats that make Mars as well as some of Jupiter's and Saturn's moons ideal candidates for research. In a final chapter she looks beyond the solar system, searching for Earth-like planets or dusty disks of preplanetary material surrounding stars.
Beginning to answer the question "Are we alone?" Astrobiology summarizes what is known and can be extrapolated from our studies of Earth, the solar system, and the galaxy.