GLG 111 Lecture Notes - Lecture 1: Peridotite, Solar Wind, Convergent Boundary
Document Summary
Figuring out how and why the earth formed is one of the greatest challenges in geology. Understanding the origin in earth is in the examination of rocks. Earth is about 4. 5 billions of years old, where the oldest minerals are around 4. 4 billions of years old. Rocks were recycled by weathering, erosion, metamorphism, dynamic resurfacing of the planet by plate tectonics, and melting. Meteorite samples and rocks from the moon are older than earth"s oldest rocks. Information on the planets comes from telescope observations but mostly from data- collecting instruments on spacecrafts that pass close to the other bodies. The inner planets: mercury, venus, earth, and marsare relatively small and dense which implies that they are mostly made of solid rock. The outer planets are huge and have low density which imply that they mostly consist of compressed gases with relatively small centers of ice or rock.
