Cycles, spirals and linear flows

摘要

Earth science presents a fascinating picture of the development of our planet: Rising by an accretion of solar nebula 4.5 billion years ago, the globe subsequently cools down from a molten state to a solid crust, surrounded by hydrogen and helium, an 'atmosphere' radically different from that of today. One billion years later, the first primitive forms of life appear on this planet. It takes another 1.5 billion years for photosynthetic life to develop, resulting in a slow increase in atmospheric oxygen, and enabling finally the creation of higher organisms. Today, the biosphere is the most complex and sophisticated system that one can imagine.