GEOL 212 Lecture Notes - Lecture 54: Perseids, Meteorite Fall, Terminal Velocity
27 Dec 2017
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Document Summary
A member of the perseid meteor shower from national geographic. The purpose of this lecture is to add depth to your knowledge of the last source, meteorites and provide a sense of the kind of solar. Fusion and ablation: meteoroids are transformed by their passage through the atmosphere: fusion rind: frictional heating begins at an altitude of ~120 km (in the thermosphere). Typically, these are completely melted during their atmospheric passage. Those that don"t vaporize survive to form cosmic spherules. Very small particles with high surface to volume ratios can be slowed down rapidly, then fall at a low terminal velocity: tektites: not really meteorites. Beads of glassy material formed from molten ejecta of large impacts. Discovery: we obtain access to meteorites in two distinct ways: meteorite finds: recognition of a meteorite on the surface. In this case, the meteorite is recognized as such by its unusual characteristics (if it has any. )
