Abstract
The study of the origin and evolution of life
cannot be separated from the study of the origin and
evolution of the Earth. In this paper, I focused on the
latter studies to understand how our planet was formed
and how its early environment was evolved. First, I
reviewed the over-all formation and evolution of the
solar system based on “Kyoto model.” Then, I
proposed a new scenario of the early evolution of
terrestrial planets especially for the Earth’s early
environment. Through these scenarios, I discussed how
to make a habitable planet and what mechanisms are
essential to make a planet habitable. The university and
diversity of the evolution of life in the Universe is one of
the key questions to understand the origin and evolution
of life on our Earth. However, these questions are
highly complicated and cannot be solved through
astronomy alone. I believe that multidisciplinary
integration of planetary science, geology, and biology is
imperative to promote the new science-field,
Astrobiology.
