AS101 Lecture Notes - Volcanism, Radioactive Decay, Basalt
Document Summary
A planet"s outer layer of cool, rigid rock is called the lithosphere. It floats on the warmer, softer rock that lies beneath the surface. P waves push matter back and forth. S waves shake matter side to side. P waves go through earth"s core but s waves don"t. Earth"s core must have a liquid outer layer. Gravity pulls high density materials to center. Accretion and differentiation when planets were young. Radioactive decay is most important heat source today. Convection- transports heat as hot material rises and cool material falls. Conduction- transfers heat from hot material to cold material. Smaller worlds cool off faster and harder earlier. Mercury and the moon are now geologically dead since their interiors have cooled down. A world can have a magnetic field if charged particles are moving inside. 3 requirements: molten interior, convection, moderately rapid rotation. Impact cratering: impacts by asteroids or comets. Volcanism: eruption of molten rock onto surface.
