Overview and perspectives of Astrobiology

Abstract

Astrobiology concerns with the origin, evolution, habitability, and future of life on Earth and elsewhere in the context of cosmic evolution. More than 50 years after the emergence of the science of Astrobiology, mankind has made tremendous progress in understanding the origin of life, co-evolution of life and Earth environments, planetary habitability, life detection, and planetary protection and exploration. The multidisciplinary nature of Astrobiology has stimulated interdisciplinary collaborations between Life Sciences, Earth and Planetary Sciences, and Space Sciences. The search for extraterrestrial life in the solar system and beyond is the driving force behind the exploration of the universe. Earth is the only known planet on which life has been developed; therefore, the formation and evolution of habitable environments as well as life on Earth are of great interest to astrobiologists. Studies regarding prebiotic chemistry and early Earth planetary environments could lead to a better understanding of the emergence of life. The tolerance of microorganisms towards planetary field analogue extreme environments on Earth provides great insights into the physical and chemical boundaries of life. The requirements for life on Earth and its environmental limits further provide useful information to assess the habitability of other bodies within our solar system (such as Mars, Jupiter’s moon Europa, and Saturn’s moon Enceladus) and beyond. Recent exploration has suggested that ancient Mars had experienced periods of warmer climate with liquid water on the surface and that at least five planetary objects in our solar system (such as Europa and Enceladus) contain subsurface oceans. Till now, more than four thousand exoplanets have been discovered, which holds the promise to identify and characterize potentially Earth-like habitable worlds beyond our solar system. Here, we review the history of and major advances that built Astrobiology, with emphases on the origin and early evolution of life on Earth, the formation and evolution of habitable planets, the search for life in the universe, the propagation of life in space, and the planetary exploration and protection. Recently, China launched a long-term strategy on deep space exploration, which provides a great opportunity to develop Astrobiology. We provide here perspectives on the development of Astrobiology in China, including the development of China Astrobiology roadmap and strategies for deep space exploration, the establishment of the Astrobiology Society of China, the corresponding higher education system, and the public education.