ASTR 3 Lecture Notes - Lecture 7: Aurora, Lithosphere, Basalt
Document Summary
Lecture 7 terrestial planets mercury, venus, earth (& earth"s moon), mars. Earth is geologically active b/c it is big enough of a planet to still have a hot interior. Lithosphere: cool rigid rock that forms a planet"s outer sphere (crust + some mantle) Mantle: rocky material such a minerals containing si, o, and other elements. Crust: rock such as granite and basalt (volcanic rock) Can detect type of material in the earth b/c seismic waves generated by earthquakes probe the earth"s. *if the lithosphere is near the surface then the planet will be geologically active! interior and diff kind of waves move @ diff speeds/directions depending on properties of layers. Sources of internal heat: accretion gravitational pe of accreting planetesimals; collisons add heat, differentiation sinking of heavier elements adds heating. Differentiation converts gravitational pe heat: radioactivity emitted particles carry ke which heat when absorbed. In mantle, as planet cools, internal heat planetary surface.
