ERS120H5 Midterm: ERS120 Term Test 1 Review Sheet.doc
Document Summary
Some gases may be added by passing comets. Formation of inner & outer planets: planetesimals exerted gravity to pull in other objects nearby, later grew into protoplanets, eventually incorporating all the debris within its orbit, it became a full-fledged planet. Differentiation of earth internal layering: large planetesimals heated up, transformation of kinetic energy into thermal energy during collisions, decay of radioactive elements, bombarded by meteorites. Iron alloy separated out and sank to the centre of the body; rocky materials remained in a shell surrounding the centre. Formation of the moon: mars-sized protoplanet slammed into newborn earth, colliding body disintegrated, along with large part of earth"s mantle, ring of debris formed around earth quickly coalesced to form the moon. Differences between gaseous outer and rocky inner planet. Terrestrial planets; consist of a shell of rock surrounding a ball of metallic iron alloy. Gas-giant planets; mass consists of gas and ice.
