The Ice Age
What was the Ice Age? How do we know it happened? And will it happen again? This video should by rights be called "The Ice Age Made Easy", but I want to reserve that title for the series of videos I made showing the evidence for our origins. But the principle is the same -- what happened and how do we know. CORRECTION: At 5:55 I called O-16 the "stable" form of oxygen. But in fact, both O-16 and O-18 are stable. I should have said O-16 is the most abundant.