How did life begin on Earth?
The earliest of humanity's history records speculations about how life began. It is a very practical question, relating to such issues as the relationship between the ecosystem and the environment of the Earth, but it is also deeply tied to humanity's quest to understand itself and where it came from. Our understanding of how easy or difficult it is for life to form directly affects our thinking about whether or not we are alone in the cosmos.
NASA's astrobiology program broadly addresses the origin and evolution of life in the universe. Part of this research is aimed at understanding how life began on Earth. This includes:
- studying the geology of the Earth, including its oldest rocks, to understand the the environment in which the earliest life began
- creating computer models of the atmosphere and oceans, which suggest the nature of this early environment
- finding the oldest fossils and other indications of the beginnings of life
- using new molecular biology techniques to learn how all of the various life forms on Earth are related, and what common evolutionary ancestors they had
- examining current life forms that exist under extreme conditions, expanding our ideas about the limits under which life can survive
- performing laboratory experiments on the chemical processes that could have led to early life forms