NATS 1740 Lecture Notes - Lecture 9: Terrestrial Planet, Earth Structure, Plate Tectonics

• School: York University
• Department: Natural Science
• Course: NATS 1740
• Professor: Radu Campeanu

Document Summary

Lecture 9 - earth and the terrestrial planets. Why is the sky blue ? (explain in terms of reflection/refraction) Explain the meaning of a red-shifted star spectrum. Planets orbits and speed: mercury 48km/s, earth 29. 8 km. s, pluto 5km/s. Earth is more massive than mars or venus, has 70% of surface covered with water. Density of material doubles as one goes to its deeper layers. The outer crust has 10-50km (5-10km in ocean beds) A mantle of denser rock has 2,900km. The outer core (iron, nickel) is liquid and has 2,200km. The inner core is solid and has 1,300km. Geophysicists determine all this from the study of seismic waves. Crust + outer mantle(lithosphere) which is rigid and brittle. Eight large (plus many small) plates flow very slowly on top of the inner mantle. At boundaries magma rises and creates new crust structures (ex. mid-atlantic ridge). Some short-lived volcanoes appeared in hot spots in the middle of a plate (ex.