It came in vertically, punching a hole 10 km wide through the atmosphere, generating temperatures so high that the air itself started to burn. When it hit the ground near the Gulf of Mexico, rock turned to liquid and spread outward in mountainous waves, not freezing until it had formed a crater 200 km across.
That was only the beginning of disaster: now the real tragedy began. Nitric oxides rained from the air, turning the sea to acid. Clouds of soot from incinerated forests darkened the sky, hiding the sun for months. Worldwide, the temperature dropped precipitously, killing off most of...