ASTR 1000 Lecture Notes - Lecture 15: Terrestrial Planet, Volcanism, Plate Tectonics
11 Oct 2016
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Document Summary
Planetary surface processes: impact cratering, volcanism, tectonics, erosion. *processes influenced by planetary size (more heat in larger planets = more volcanic and tectonic behavior), orbital distance, and rotation* Impact cratering form when asteroids crash into the face of a planets. Impacts can vaporize both target & ejector, carving out a depression. Ejecta material blasted away from impact site. Crater morphology: usually shaped like a cereal bowl (10 km or less, ejecta in every direction, some craters have central peaks or concentric rings. Formed by the rebound of the enter crater during the impact: all craters will be symmetrical unless the impact was at a low angle (>10 degrees) Learning from craters: tells us about the size of the impactors, crater shape tells us about the target, craters can reveal what lies beneath planetary surfaces, the surface age (or the time since the surface last cooled) *we have rocks from the moon & have measured their age, allowing us to correlated.
