How did the planets of the solar system come about? How did the atmosphere change and evolve through time? What where the major geological and biological events of Earth history?

Essay by kuzaHigh School, 10th grade November 2003

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Earth has a lengthy and intricate history. The changes that occur are two slow for people to be conscious about. Awareness of the theory of evolution is quite fresh, yet we have made a lot of progress. We will start our journey through the Earth's evolutionary timeline from nearly 5 billion years ago. Earth and nine additional planets revolve around the sun. Our researchers have reasons to believe that all the planets in our solar system formed at the same time.

About 5 billion years ago a huge cloud of gasses consisting of hydrogen and helium began to gravitationally contact, forming into a flat disk shaped material called the protosun (pre-Sun). The compaction and the gravitational pressure caused the temperature of the center of this mass to radically rise. The huge mass in the middle formed into the Sun. However, the rotational motion continued, and the remaining dust and gasses continued to orbit this central body until eventually forming into the planets of the solar system.

This is a simple way of looking at the nebular hypothesis.

The air that we breathe today is a mixture of nitrogen, oxygen and argon (78%, 21%, 1%.) But, the atmosphere that existed several billion years ago was totally different. The original atmosphere was probably swept away by the solar wind, a strong flow of elements discharged by the Sun. In time, the process of outgassing released gas from the inside of the Earth. This process is still happening through today's volcanoes. The plants of today have existed for long periods of time. A large part of the formation of the current atmosphere is due to their process of photosynthesis. They produce oxygen after breaking down light energy from synthesized sugars that they obtain from carbon dioxide that we emit. We process the oxygen...