Astronomy 1021 Lecture Notes - Lecture 3: Radioactive Decay, Surface 3, Geology Of The Moon

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Sarah Gallagher

Document Summary

We can infer the density of structure of earth interior by using seismic waves. They have different regions because of differentiation: gravity pulls high density material to center, lower density material rises to surface. Planets interiors: heating process: accretion and differentiation when planets were young, radioactive decay is most important heat source today. Planets interiors: cooling process: convection- transports heat: hot material rises, cool material falls, conduction- transfers heat: from hot material to cool material, radiation sends energy into space. Smaller worlds cool off faster and harden earlier. Larger worlds remain warm inside, promoting volcanism and tectonics. Larger worlds also have more erosion because their gravity retains an atmosphere. Moon and mercury are now geologically dead. Geological activity causes changes on a planets surface. Moon and mercury as geologically dead: no more current geological activity. Surfaces look pretty much the same now as they did long ago.