This paper is comprised of 6 sections as follows.
(1) Introduction
(2) Planetary Formation Theory and Origin of Earth
(3) Origin of a habitable planet: carbon cycle
(4) Origin of the Earth’s life
(5) Evolution of the Earth’s life
(6) Towards the establishment of Astrobiology
In (1) Introduction, I briefly summarized why I came to involve in these research topics. In (2) Planetary Formation Theory and Origin of Earth, we simply review previous researches of planetary formation theory, and introduce newly proposed Tandem model to explain the formation of the solar system with new factor. Then, we introduce the ABEL model as another new theory to explain how the Earth was formed. This model can explain long unsolved enigma of the origin of earth’s water and solid earth. In (3) Origin of a habitable planet: carbon cycle, we try to explain the significance to unravel the carbon cycle through earth’s history. And we propose new concept of carbon cycle from atmosphere to mantle through earth’s history from the birth of earth to present day. In addition, based on accretionary complex geology centering on Ocean Plate Stratigraphy (OPS), we propose carbon compensation depth (CCD) works as the function of pCO2 through time, which is significantly new method to approach environmental evolution of the earth. In (4) Origin of the Earth’s life, after we review previous researches for the birthplace of life, we propose nine requirements that must be met at the birthplace of life. Then, we introduce an ideal site to emerge life is Natural geyser system on the Hadean primordial continent, which produce material circulation system to synthesize life by the combination between natural nuclear reactor and geyser. In (5) Evolution of the Earth’ life, we pick up 20 biggest events in the history for the earth and life, to understand more essential and significant events to study the history of earth and life. Those events were selected considering the criterion to extract, whether the event is single and unique phenomenon to become a turning point for the earth’s history. In (6) Towards the establishment of Astrobiology, we propose the working hypothesis to push forward the present Astrobiology research. Astrobiology is the research field to unravel when, how, and where in the universe life was born. To tackle with such a big question, fundamental requirements must be clarified. The conditions to evolve to a habitable planet, which we propose here, is comprised of three groups; (1) planetary requirements to be life emerging planet, (2) nine requirements for the birthplace, and (3) requirements to evolve into planet with civilization. Totally 40 requirements are picked up, and each condition must be satisfied in sequence as listed. It means the emergence of life is not easy. The order and number of requirements that must be satisfied make life very difficult even to appear, suggesting the planet with civilization might be quite rare in our Galaxy.