Click on image for full size version (14K)

We've discussed the collapse of the solar nebula, planetismals sweeping up material, including the possibility of comets bringing volatiles into the inner solar system, the differentiation of the terrestrial planets, and we've discussed the T-Tauri phase of the Sun. Once the T-Tauri phase was complete, and the solar system was swept clean of material left over from the solar nebula, the planets can be considered to be officially "born". At this period, most geologists start the Earths geologic "clock". According to geologic time, Earth "began" life in the Archean age, which began at this time.

At this time, the Earth's surface was very hot and was still cooling. This would be a remnant of the process of differentiation. This means that there was no ocean on the Earth, and the rocks were probably all igneous rocks. We discussed where the original atmosphere might have come from. Scientists know that whatever the atmosphere was prior to this time, at this point in history, the atmosphere of Earth began to change. The amount of nitrogen in the Earth's atmosphere is 10,000 more that it should be if the atmosphere was the same as that of the sun and stars. This means that all the extra nitrogen in the Earth's atmosphere is new and must have come from somewhere. Moreover, with small planets like the Earth, Mars and Venus the atmosphere will eventually drift away unless it is replenished somehow.

Click on image for full size version (14K)

We've discussed the collapse of the solar nebula, planetismals sweeping up material, including the possibility of comets bringing volatiles into the inner solar system, the differentiation of the terrestrial planets, and we've discussed the T-Tauri phase of the Sun. Once the T-Tauri phase was complete, and the solar system was swept clean of material left over from the solar nebula, the planets can be considered to be officially "born". Now the Earths geologic "clock" starts to run. The first age of the Earth's history is called the Archean age. The Archean age started at this time.

Earth's surface was very hot and was still cooling. This means that there was no ocean on the Earth. We don't know for sure, but the rocks were probably all igneous rocks because they came out of volcanoes. Whatever the atmosphere there was prior to this time, at this point in history, the atmosphere of Earth began to change.

Click on image for full size version (14K)

The beginning of the solar system was in the shrinking of the nebula to form the proto-sun, the forming of planetismals to sweep up smaller rocks until a planet is formed, comets bringing water to the inner planets, these planets turning inside-out and separating into layers, and the sun entering its T-Tauri phase. Once the T-Tauri phase was complete, and the solar system was swept clean of material left over from the solar nebula, the solar system was officially "born". Now the Earths geologic "clock" starts to run. The first age of the Earth's history is called the Archean age. The Archean age started at this time.

Earth's surface was very hot and was still cooling. This means that there was no ocean on the Earth. We don't know for sure, but the rocks were probably all igneous rocks because they came out of volcanoes. Whatever the atmosphere there was prior to this time, at this point in history, the atmosphere of Earth began to change.

The beginning of the solar system was in the shrinking of the nebula to form the proto-sun, the forming of planetismals to sweep up smaller rocks until a planet is formed, comets bringing water to the inner planets, these planets turning inside-out and separating into layers, and the sun entering its T-Tauri phase. Once the T-Tauri phase was finished, the solar system was officially "born". Now the Earths geologic "clock" starts to run. The first age of the Earth's history is called the Archean age. The Archean age started at this time.

Earth's surface was very hot and was still cooling. This means that there was no ocean on the Earth. We don't know for sure, but the rocks were probably all igneous rocks because they came out of volcanoes. Whatever the atmosphere there was prior to this time, at this point in history, the atmosphere of Earth began to change.