look up Younger Dryas Impact and ignore the establishment dead-enders. It happened. Changed Everything. We remembered it. Proof is in the ground now, nearing acceptance stage of academic grief.
The ‘comet’ that probably crunched the Laurentide Ice Sheet, 12000 years ago. Sent a warming world back into another millennium of ice age and perhaps helped kill off the Pleistocene megafauna ( along with our help)