Guided Exploration: Origins
Overview: Because Earth is dynamic, all the material on its surface has changed since the planet formed some 4.6 billion years ago. Some meteorites, on the other hand, have remained unchanged as they travel through the vacuum of space, so they contain important information about physical and chemical processes at work in the early solar system. The chondrite meteorites in this section are the most common type collected on Earth.
1. These three cases “take apart” primitive meteorites into three components:
• Chondrules: Under a microscope, these glassy beads are revealed in the thin section of Allende. Read about what the chemical composition of primitive meteorites tells us about the solar system.
• CAIs: Calcium-aluminum inclusions are the oldest rocks that formed in our solar system. Investigate how scientists determine the age of mineral inclusions, and why that information is significant.
• Matrix: Dust from the early solar system has been preserved as matrix, a dark, fine-grained material surrounding chondrules and CAIs. Explore why some meteorites, such as Murchison, are black like tar and others are much lighter in color. Don’t miss the presolar grains extracted from the Allende meteorite.
2. To learn more about the early formation of the solar system, explore these three cases:
• Parent Bodies: By analyzing their composition, scientists can determine if meteorites came from the same source. Find three meteorites (Kunashak, Kyushu, Suizhou) and explore why they may have belonged to the same parent body. Even though they fell to Earth at different times and places, their composition is identical.
• Solar System: The chemical makeup of meteorites and the planets in our solar system relates to distance from the Sun. Compare the chemistry and origin of three different meteorites (Eagle, Farmington, Banten).
• Planetesimals: Meteorites record the processes — such as heating, melting, and pulverizing — that occured when objects in the early solar system collided. Examine the specimens and explore the processes.