GEOL 101 Study Guide - Quiz Guide: Geocentric Model, Geothermal Gradient, Oceanic Crust
Document Summary
1:53 pm: the geocentric model of the universe placed the earth at the center of the. The heliocentric model placed the sun at the center: the earth is one of eight planets orbiting the sun. The solar system lies on the outer edge of the milky way galaxy. These atoms formed vast gas clouds, called nebulae: only very small atoms formed during big bang nucleosynthesis. The earth, and the life forms on it, contain elements that could have been produced only during the life cycle of stars. Thus, we are all made of stardust: gravity causes clumps of gas in the nebulae to coalesce into flattened disks with bulbous centers. As the central ball of this accretionary disk collapsed inward, it became a warm protostar. Eventually, the became so hot and dense that fusion reactions began and it became a true star: planets developed from the rings of gas and dust surrounding newborn stars.
