ABSTRACT
This chapter provides an overview of astrobiology, which includes its definition, scope, a brief history, and classification as a field of study. Astrobiology is a young science that acquired its name only in 1995. Astrobiology evolved from its predecessor, exobiology, which is the study of the origin of life and of possible life outside Earth. Prebiotic reactions under the conditions of hydrothermal vents gained importance, since such vents on Earth are rich with life. The major hypothesis about the origin of life on Earth, which later became accepted as a key foundation of both exobiology and astrobiology, was proposed independently by A. I. Oparin in 1924 and J. B. S. Haldane in 1929. Rapid developments in astrobiology and astrobiology-relevant disciplines led to an expanded list, which included cosmology, atmospheric science, oceanography, evolutionary science, paleontology, planetary science, biochemistry, molecular biology, microbiology, and ecology. Interdisciplinary and transdisciplinary nature of astrobiology is especially needed for the study of cosmic evolution.
