IM, I see a future in science for you. As noted, the theory this research team is working on is that a comet exploded in the atmosphere somewhere over eastern Canada about 12,900 years ago. It set off a series of events of which the evidence can be seen across much of North America. I don't profess to understand the whole thing, but the bottom line is that the earth's climate changed soon after the event and resulted in the extinction of many large mammals and the Clovis people. There are some who contest it, but that's the way science works; propose a theory with evidence to support it and then let people take pot shots at it to find the flaws.
