<human>:  Why did the apocalypse happen in the movie ‘End of the World’?
<bot>: The apocalypse happened because the asteroid hit Earth. The asteroid was made of a material called pallasite, which was a type of iron meteorite. The asteroid was about 20 miles wide, and it was traveling at a speed of about 35,000 mph when it hit Earth. The impact created a crater that was about 1 mile wide and 50 miles long. The asteroid broke up into smaller pieces after the collision, and these pieces were thrown into the atmosphere, causing the firestorms.