Though a common premise in science fiction, the prospect of a large asteroid smashing into Earth is not fiction at all, but rather a guarantee. Extinction-event asteroids are a periodic occurrence, just like the tides or the full moon; just ask the dinosaurs. That's why the National Aeronautics and Space Administration (NASA) spent so much time and money on the Double Asteroid Redirection Test (DART) mission, which successfully tested our ability to deflect an asteroid from hitting Earth. That mission was a success, and (seemingly) suggests that asteroids aren't as dangerous as one might think.
But what if the asteroid in question was almost indestructible?
