Astronomy 1021 Lecture Notes - Lecture 7: Bahariya Oasis, Torino Scale, Selenga River

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Robert Cockcroft

Document Summary

Seismic waves: earthquakes, volcanic eruptions, landslides, etc, most direct, density structure. Seismic waves on moon: seismic monitors on the moon, moonquakes and meteor impacts detected. Other interior measurements: gravitational field, magnetic field, volcanic rocks. Differentiation: high-density material sinks to center, lower-density material floats to surface, indicates molten past. Gravitational potential energy converted to thermal energy. Bigger objects take longer to cool: radioactivity. Effects of eternal heating: liquid part of core, moving charged particles, magnetic field. Terrestrial planet interior: mercury: large core surface ripped off, moon: tiny core made from earth"s surface. Geological activity: planetary surface changes, primary driver: internal heat, four major processes. 1: craters ten times wider than object that made them, small craters greatly outnumber large ones, tremendous explosion. Torino scale: assessing asteroid and comet impact hazard predictions, certain collisions: 8 localized destruction: once every 50-1000 years. 9 regional destruction: once per 10,000-100,000 years.