Randall Carlson does a nice job explaining subjects which would otherwise be incredibly dense. I especially enjoyed this entire series: Cosmography 101. In this series he points out that ancient humans around the time of the last ice age appear to have been cosmographists. With this in mind he explores various scenarios of what might have occurred based on geological evidence. Once you finish hearing what Carlson presents I am certain you will know more than you wanted about the Younger Dryas. You will also encounter many comprehensive descriptions of comets and asteroids. Unfortunately for Carlson, his ideas on the events of the last ice age are an anathema to some of the worlds popular ideologies: those who hold a religious based on the Bible’s account of a supernatural guiding force and those who hold a scientific view based on gradualism. If you maintain a religious understanding, then the proof that these historical events occurred through purely physical interactions between material things following mathematical laws, then you will most likely close your attention to the evidence immediately. The same refusal will occur by those scientifically oriented who think their already correct view of this time era is true and scientifically valid. Dare to be challenged?