ASTR 101 Lecture Notes - Lecture 34: Gravity Anomaly, Cellophane, Blast Furnace

• School: Queen's University
• Department: Physics, Engineering Physics and Astronomy
• Course: ASTR 101
• Professor: David Alan Hanes

Document Summary

Hypothesis of extinction of dinosaurs: somehow climatological change lead to conditions in which the dinosaurs could no longer prosper but other animals could. Fossil records indicated dinosaurs dominant land and sea species for many millions of years, but then vanished 65 million years ago. Happened between cretaceous and tertiary, but don"t know how long. First evidence suggesting a catastrophic event is the discovery of the thin kt layer. Is seen world-wide, typically several cm thick. Is considerably thicker in southern parts of north america. There are different fossils (including micro-organisms) are seen above and below the layer) Much more iridium in the layer than you would expect (but still just a few parts per billion) At a murder scene, we find a tiny trace of dna (perhaps from a drop of sweat) although person can claim never to have been there. It"s not the dominant material present, but it is surprising to find it at all.