Bringing-real-science-to-fiction Stories

What really happened when a comet bashed into the Earth around 13,000 years ago? I have thought about this question and this novel, or maybe even a series is the result. There are two major human species in the world of Yo-Ra one is similar to modern Humans, in culture and physical features, development. The other speices is similar to Desinovian-Neanderthal in culture and physical features, but they also have other mental abilites that modern Humans don't have.