ERS120H5 Study Guide - Midterm Guide: Depositional Environment, Siltstone, Smog
Document Summary
Lecture 2 : formation and structure of earth: describe formation of solar system including sun and orbiting planets. Midterm review sheet: a nebula forms from hydrogen, helium and helium left over from big bang. Nebula condenses into a swirling disc, with a central ball surrounded by rings. Ball at centre grows dense and hot enough for fusion becomes the sun. In the rings, dust particles collide and stick together, forming planetesimals. Planetesimals grow into the proto-earth; interior heats up and becomes soft. Gravity reshapes proto-earth into a sphere; interior differentiates into a core and mantle. Soon after earth forms, a small planet collides with it blasts debris forming a ring around. The moon forms from the ring of debris. Atmosphere develops from volcanic gases; when the earth becomes cool enough, moisture condenses and rains to create the oceans. Some gases may be added by passing comets.
