Chapter 1
Themes of Textbook
The Earth is a unique, evolving system. Within the Earth System, chemical elements pass in cycles between different types of rock and sea, rock, and air.
Plate Tectonics explains many Earth processes. Earth has a core, mantle, and crust.
Measurements:
1 Ka=1 thousand years ago
1 Ma=One million years ago
1 Ga=One billion years ago
The Earth is 4.57 billion years old.
Big Bang
All matter and energy was initially packed into a small point
The point exploded and hydrogen atoms began to form
Big bang nucleosynthesis occurred
As the Universe continued to expand and cool further, atoms and molecules slowed down and accumulated into patchy clouds called nebulae
Eventually Gravity began to remold the Universe and stars began to form.
According to the Nebula theory, the Sun and all other objects in the Solar system was formed from material swirling around in the nebula
Forming the Earth-Moon System
1. A nebula forms from hydrogen and helium
2. Gravity pulls gas and dust inward to form an accretion disk
3. Dust begins hot enough for fusion to occur
4. Dust and ice particles collide and stick together forming planetesimals
5. Gravity reshaped protoearth into a sphere
6. A small planet collides with the Earth, the debris form a ring
7. The moon forms from the ring of debris
8. The atmosphere develops from volcanic gases
9. Rain becomes abundant
The heavier elements were formed from stellar nucleosynthesis during the life cycles of existing stars.
The first Nebulae consisted of Hydrogen and Helium(light elements)
Earth and all other planets of our solar system orbit the sun; the entire universe is not Sun-centered.
When a light source moves toward you, it becomes blue as it shifts to a higher frequency; receding light shifts to red, a lower frequency.
Our solar system lies near the outer edge of the Milky Way; it formed less than 5 billion years ago;