Might a destructive comet impact in Earths far-off past have actually permanently changed human civilization?Scientists believe that a cluster of comet fragments may have smashed into Earths surface 13,000 years earlier, in the most devastating impact considering that the Chicxulub event killed off Earths big dinosaurs about 66 million years ago. Related: 4,000-Year-Old Stone Monolith Likely an Astronomical MarkerThe researchers examined the theory that a comet struck Earth 13,000 years earlier, evaluating geological information from the areas where they believe it might have hit, particularly North America and Greenland. Sweatman said in a statement.While the new research study work is suggestive and amazing, the team acknowledges that more proof and more research is essential to better comprehend how this effect might have impacted international environment and, ultimately, human civilizations, according to the statement.This work was described in a study released May 19 in the journal Earth-Science ReviewsEmail Chelsea Gohd at cgohd@space.com or follow her on Twitter @chelsea_gohd.