There is a theory[0] that a series of impact events ~12,000 years ago melted the North American ice sheets over the course of a few days. [0] https://en.wikipe

There is a theory[0] that a series of impact events ~12,000 years ago melted the North American ice sheets over the course of a few days. [0] https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesis https://en.wikipedia.org/wiki/Younger_Dryas_impact_hypothesi...