Earth’s worst day happened 66.043 million years ago — give or take 32,000 years. Let’s say it was a Monday. And if it was, then around Friday afternoon a strange new star would’ve begun growing brighter and brighter in the sky.

Tragically, it wasn’t a cool new star at all. It was a Mount Everest-sized space rock traveling 45,000 mph. Surprise! The asteroid was so gargantuan, that as its leading edge plunged into the Gulf of Mexico, you would have seen the other side was still higher than